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167 results on '"Andrea Chiavassa"'

1. Is Betelgeuse Really Rotating? Synthetic ALMA Observations of Large-scale Convection in 3D Simulations of Red Supergiants

Author

Jing-Ze Ma, Andrea Chiavassa, Selma E. de Mink, Ruggero Valli, Stephen Justham, and Bernd Freytag

Subjects
Red supergiant stars, Stellar convection envelopes, Stellar rotation, Astronomical simulations, Hydrodynamics, Radiative transfer, Astrophysics, QB460-466
Abstract

The evolved stages of massive stars are poorly understood, but invaluable constraints can be derived from spatially resolved observations of nearby red supergiants, such as Betelgeuse. Atacama Large Millimeter/submillimeter Array (ALMA) observations of Betelgeuse showing a dipolar velocity field have been interpreted as evidence for a projected rotation rate of about 5 km s ^−1 . This is 2 orders of magnitude larger than predicted by single-star evolution, which led to suggestions that Betelgeuse is a binary merger. We propose instead that large-scale convective motions can mimic rotation, especially if they are only partially resolved. We support this claim with 3D CO5BOLD simulations of nonrotating red supergiants that we postprocessed to predict ALMA images and SiO spectra. We show that our synthetic radial velocity maps have a 90% chance of being falsely interpreted as evidence for a projected rotation rate of 2 km s ^−1 or larger for our fiducial simulation. We conclude that we need at least another ALMA observation to firmly establish whether Betelgeuse is indeed rapidly rotating. Such observations would also provide insight into the role of angular momentum and binary interaction in the late evolutionary stages. The data will further probe the structure and complex physical processes in the atmospheres of red supergiants, which are immediate progenitors of supernovae and are believed to be essential in the formation of gravitational-wave sources.

Published
2024
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2. Cool, Evolved Stars: Results, Challenges, and Promises for the Next Decade

Author

Gioia Rau, Rodolfo Montez, Jr, Kenneth Carpenter, Sarah Bladh, Margarita Karovska, Vladimir Airapetian, Tom Ayers, Martha Boyer, Andrea Chiavassa, Geoffrey Clayton, William Danchi, Orsola De Marco, Andrea K. Dupree, Tomasz Kaminski, Franz Kerschbaum, Jeffrey Linski, John Monnier, Miguel Montarges, Krister Nielsen, Keiichi Ohnaka, Sofia Ramstedt, Rachael Roettenbacher, Theo ten Brummelaar, Claudia Paladini, Arkaprabha Sarangi, Gerard van Belle, and Paolo Ventura

Subjects
Astrophysics
Abstract

Cool, evolved stars are the main source of chemical enrichment of the interstellar medium (ISM), and understanding their mass loss and structure offers a unique opportunity to study the cycle of matter in the Universe. Pulsation, convection, and other dynamic processes in cool evolved stars create an atmosphere where molecules and dust can form, including those necessary to the formation of life (e.g. Carbon-bearing molecules). Understanding the structure and composition of these stars is thus vital to several aspects of stellar astrophysics, ranging from ISM studies to modeling young galaxies and to exoplanet research. Recent modeling efforts and increasingly precise observations now reveal that our understanding of cool stars photospheric, chromospheric, and atmospheric structures is limited by inadequate knowledge of the dynamic and chemical processes at work. Here we outline promising scientific opportunities for the next decade that can provide essential constraints on stellar photospheres, chromospheres, and circumstellar envelopes (CSE), and tie together analyses of the spectra and interferometric and imaging observations of evolved stars. We identify and discuss the following main opportunities: (1) identify and model the physical processes that must be included in current 1D and 3D atmosphere models of cool, evolved stars; (2) refine our understanding of photospheric, chromospheric, and outer atmospheric regions of cool evolved stars, their properties and parameters, through high-resolution spectroscopic observations, and interferometric observations at high angular resolution; (3) include the neglected role of chromospheric activity in the mass loss process of red giant branch (RGB) and red super giant (RSG) stars and understand the role played by their magnetic fields; (4) identify the important shaping mechanisms for planetary nebulae (PNe) and their relation with the parent Asymptotic Giant Branch (AGB) stars.

Published
2019

3. The Future of Exoplanet Direct Detection

Author

John Monnier, Gioia Rau, Ellyn K Baines, Joel Sanchez‐Bermudez, Martin Elvis, Sam Ragland, Rachel L Akeson, Gerard van Belle, Ryan Norris, Kathryn Gordon, Denis Defrère, Stephen Ridgway, Jean‐Baptiste Le Bouquin, Narsireddy Anugu, Nicholas Scott, Stephen Kane, Noel Richardson, Zsolt Regal, Zhaohuan Zhu, Andrea Chiavassa, Gautam Vasisht, Keivan G Stassun, Chuanfei Dong, Olivier Absi, Sylvestre Lacour, Gerd Weigelt, Douglas Gies, Fred C Adams, Nuria Calvet, Sascha P. Quanz, Catherine Espaillat, Tyler Gardner, Alexandra Greenbaum, Rafael Millan‐Gabet, Chris Packham, Mario Gai, Quentin Kral, Jean‐Philippe Berger, Hendrik Linz, Lucia Klarmann, Jaehan Bae, Rebeca Garcia Lopez, Gallenne Alexandre, Fabien Baron, Lee Hartmann, Makoto Kishimoto, Melissa McClure, Johan Olofsson, Chris Haniff, Michael Line, Romain G. Petrov, Michael Smith, Christian Hummel, Theo ten Brummelaar, Matthew De Furio, Stephen Rinehart, David Leisawitz, William Danchi, Daniel Huber, Edward Wishnow, Denis Mourard, Benjamin Pope, Michael Ireland, Stefan Kraus, Benjamin Setterholm, and Russel White

Subjects
Instrumentation And Photography
Abstract

Diffraction fundamentally limits our ability to image and characterize exoplanets. Currant and planned coronagraphic searches for exoplanets are making incredible strides but are fundamentally limited by the inner working angle of a few λ/D. Some crucial topics, such as demographics of exoplanets within the first 50 Myr and the infrared characterization of terrestrial planets, are beyond the reach of the single aperture angular resolution for the foreseeable future. Interferometry offers some advantages in exoplanet detection and characterization and we explore in this white paper some of the potential scientific breakthroughs possible. We demonstrate here that investments in "exoplanet interferometry" could open up new possibilities for speckle suppression through spatial coherence, a giant boost in astrometric precision for determining exoplanet orbits, ability to take a census of young giant exoplanets (clusters <50 Myr age), and an unrivaled potential for infrared nulling from space to detect terrestrial planets and search for atmospheric biomarkers. All signs point to an exciting future for exoplanets and interferometers, albeit a promise that will take decades to fulfill.

Published
2019

4. Precision Monitoring of Cool Evolved Stars: Constraining Effects of Convection and Pulsation

Author

Andrea Chiavassa, Willem-Jan de Wit, Kjell Eriksson, Bernd Freytag, Sara Bladh, Markus Wittkowski, Xavier Haubois, Susanne Hofner, Kateryna Kravchenko, Thibaut Paumard, Claudia Paladini, Gioia Rau, and Peter R. Wood

Subjects
Astronomy
Abstract

Mass loss from cool evolved stars is an important ingredient of the cosmic matter cycle, enriching the Universe with newly formed elements and dust. However, physical processes that are not considered in current models represent uncertainties in our general understanding of mass loss. Time-series of interferometric data provide the strongest tests of dynamical processes in the atmospheres of these stars. Here, we present a pilot study of such measurements obtained with the GRAVITY instrument on the Very Large Telescope Interferometer.

Published
2019
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5. A prototype tank for the SWGO detector

Author

Sofia Grusovin, Giovanni Consolati, Alessandro De Angelis, Cornelia Arcaro, Francesca Bisconti, Andrea Chiavassa, Michele Doro, Fausto Guarino, Mosè Mariotti, and Elisa Prandini

Subjects
High Energy Physics - Experiment (hep-ex), Physics - Instrumentation and Detectors, FOS: Physical sciences, Instrumentation and Detectors (physics.ins-det), Astrophysics - Instrumentation and Methods for Astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), High Energy Physics - Experiment
Abstract

The Southern Wide-field Gamma-ray Observatory (SWGO) is an international collaboration working on realizing a next-generation observatory located in the Southern hemisphere, which offers a privileged view of our galactic center. We are working on the construction of a prototype water Cherenkov detector at Politecnico di Milano using a flexible testing facility for several candidate light sensors and configurations. A structure able to hold different types of detectors in multiple configurations has been designed, built and tested in Politecnico's labs. Furthermore, an analytical study of muons and electrons showers has been carried out using the SWGO observatory simulation software to examine the correlation between the detection capabilities of the prototype tank and its water level.

Published
2023

6. Presence of liquid water during the evolution of exomoons orbiting ejected free-floating planets

Author

Giulia Roccetti, Tommaso Grassi, Barbara Ercolano, Karan Molaverdikhani, Aurélien Crida, Dieter Braun, and Andrea Chiavassa

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), Physics and Astronomy (miscellaneous), Space and Planetary Science, Earth and Planetary Sciences (miscellaneous), FOS: Physical sciences, Ecology, Evolution, Behavior and Systematics, Astrophysics - Earth and Planetary Astrophysics
Abstract

Free-floating planets (FFPs) can result from dynamical scattering processes happening in the first few million years of a planetary system's life. Several models predict the possibility, for these isolated planetary-mass objects, to retain exomoons after their ejection. The tidal heating mechanism and the presence of an atmosphere with a relatively high optical thickness may support the formation and maintenance of oceans of liquid water on the surface of these satellites. In order to study the timescales over which liquid water can be maintained, we perform dynamical simulations of the ejection process and infer the resulting statistics of the population of surviving exomoons around free-floating planets. The subsequent tidal evolution of the moons' orbital parameters is a pivotal step to determine when the orbits will circularize, with a consequential decay of the tidal heating. We find that close-in ($a \lesssim 25 $R$_{\rm J}$) Earth-mass moons with CO$_2$-dominated atmospheres could retain liquid water on their surfaces for long timescales, depending on the mass of the atmospheric envelope and the surface pressure assumed. Massive atmospheres are needed to trap the heat produced by tidal friction that makes these moons habitable. For Earth-like pressure conditions ($p_0$ = 1 bar), satellites could sustain liquid water on their surfaces up to 52 Myr. For higher surface pressures (10 and 100 bar), moons could be habitable up to 276 Myr and 1.6 Gyr, respectively. Close-in satellites experience habitable conditions for long timescales, and during the ejection of the FFP remain bound with the escaping planet, being less affected by the close encounter., Comment: 21 pages, 12 figures, accepted for publication on International Journal of Astrobiology

Published
2023
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7. A dusty veil shading Betelgeuse during its Great Dimming

Author

Stefan Kraus, Eric Lagadec, E. Cannon, Florentin Millour, Guy Perrin, A. de Koter, John D. Monnier, Andrea Chiavassa, Xavier Haubois, Claudia Paladini, Narsireddy Anugu, Peter Scicluna, Andrea K. Dupree, L. Decin, Philippe Stee, Bruno Lopez, Gioia Rau, M. Montargès, William C. Danchi, K. Kravchenko, S. T. Ridgway, Ryan P. Norris, J. Sanchez-Bermudez, Pierre Kervella, Faustine Cantalloube, J-B. Le Bouquin, Markus Wittkowski, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Instituut voor Sterrenkunde [Leuven], Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), Laboratoire Lagrange, Université Côte d'Azur, Observatoire de la Côte d'Azur, CNRS., Anton Pannenkoek Institute for Astronomy [University of Amsterdam], University of Amsterdam [Amsterdam] (UvA), Max Planck Institute for Astronomy (MPIA), Instituto de Astronomía, Univ. Nacional Autónoma de México, Universidad Nacional Autónoma de México (UNAM), European Southern Observatory [Santiago] (ESO), European Southern Observatory (ESO), School of Chemistry [Leeds], University of Leeds, Max Planck Institute for Extraterrestrial Physics (MPE), Max-Planck-Gesellschaft, Harvard-Smithsonian Center for Astrophysics (CfA), Smithsonian Institution-Harvard University [Cambridge], NSF’s National Optical-Infrared Astronomy Research Laboratory (NOIRLab), Steward Observatory, University of Arizona, School of Physics and Astronomy [Exeter], University of Exeter, Physics Department [New Mexico Institute of Mining and Technology], New Mexico Institute of Mining and Technology [New Mexico Tech] (NMT), GSFC Exoplanets and Stellar Astrophysics Laboratory, NASA Goddard Space Flight Center (GSFC), Department of Physics [Catholic University of America], Catholic University of America, Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Department of Astronomy University of Michigan, University of Michigan [Ann Arbor], University of Michigan System-University of Michigan System, Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA), Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and Low Energy Astrophysics (API, FNWI)

Subjects
Brightness, SURFACE, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, STELLAR CONVECTION, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Apparent magnitude, INTERSTELLAR SILICATE MINERALOGY, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, IIP SUPERNOVA, Red supergiant, 010306 general physics, 010303 astronomy & astrophysics, Stellar evolution, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, ComputingMilieux_MISCELLANEOUS, Betelgeuse, Physics, Photosphere, Multidisciplinary, Science & Technology, Multidisciplinary Sciences, Supernova, Neutron star, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, [SDU]Sciences of the Universe [physics], NEAR-IR, Science & Technology - Other Topics, RED SUPERGIANTS, STEPS, Astrophysics::Earth and Planetary Astrophysics
Abstract

Red supergiants are the most common final evolutionary stage of stars that have initial masses between 8 and 35 times that of the Sun1. During this stage, which lasts roughly 100,000 years1, red supergiants experience substantial mass loss. However, the mechanism for this mass loss is unknown2. Mass loss may affect the evolutionary path, collapse and future supernova light curve3 of a red supergiant, and its ultimate fate as either a neutron star or a black hole4. From November 2019 to March 2020, Betelgeuse—the second-closest red supergiant to Earth (roughly 220 parsecs, or 724 light years, away)5,6—experienced a historic dimming of its visible brightness. Usually having an apparent magnitude between 0.1 and 1.0, its visual brightness decreased to 1.614 ± 0.008 magnitudes around 7–13 February 20207—an event referred to as Betelgeuse’s Great Dimming. Here we report high-angular-resolution observations showing that the southern hemisphere of Betelgeuse was ten times darker than usual in the visible spectrum during its Great Dimming. Observations and modelling support a scenario in which a dust clump formed recently in the vicinity of the star, owing to a local temperature decrease in a cool patch that appeared on the photosphere. The directly imaged brightness variations of Betelgeuse evolved on a timescale of weeks. Our findings suggest that a component of mass loss from red supergiants8 is inhomogeneous, linked to a very contrasted and rapidly changing photosphere. The southern hemisphere of Betelgeuse during its Great Dimming was an order of magnitude darker than usual, owing to a cool patch on the photosphere and associated dust formation.

Published
2021

9. The circumstellar material around the Type IIP SN 2021yja

Author

Alexandra Kozyreva, Jakub Klencki, Alexei V. Filippenko, Petr Baklanov, Alexey Mironov, Stephen Justham, and Andrea Chiavassa

Subjects
High Energy Astrophysical Phenomena (astro-ph.HE), Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, Solar and Stellar Astrophysics (astro-ph.SR)
Abstract

The majority of Type II-plateau supernovae (SNe IIP) have light curves that are not compatible with the explosions of stars in a vacuum; instead, the light curves require the progenitors to be embedded in circumstellar matter (CSM). We report on the successful fitting of the well-observed SN IIP 2021yja as a core-collapse explosion of a massive star with an initial mass of ~15 Msun and a pre-explosion radius of 631 Rsun. To explain the early-time behaviour of the broad-band light curves, the presence of 0.55 Msun CSM within ~2x10^14 cm is needed. Like many other SNe IIP, SN 2021yja exhibits an early-time flux excess including ultraviolet wavelengths. This, together with the short rise time (, 15 pages, 10 figures, accepted for publication in ApJL

Published
2022

10. Coupling 3D Simulations to Study Stellar and Planetary Atmospheres

Author

Maria Chiara Maimone, Andrea Chiavassa, Jeremy Leconte, and Matteo Brogi

Abstract

What makes the study of exoplanetary atmospheres so hard is the extraction of its tiny signal from observations, usually dominated by telluric absorption, stellar spectrum and instrumental noise. The High-Resolution Spectroscopy has emerged as one of the leading techniques for detecting atomic and molecular species (Birkby, 2018), but although it is particularly robust against contaminant absorption in the Earth’s atmosphere, the non-stationary stellar spectrum — in the form of either Doppler shift or distortion of the line profile during planetary transits — creates a non-negligible source of noise that can alter or even prevent the detection. Recently, significant improvements have been achieved by using 3D, radiative hydrodynamical (RHD) simulations for the star and Global Circulation Models (GCM) for the planet (e.g., Chiavassa&Brogi 2019, Flowers et al. 2019). However, these numerical simulations have been computed independently so far, while acquired spectra are the result of the natural coupling at each phase along the planet's orbit. With my work, I aim at generating emission spectra of G, F, and K-type stars and Hot Jupiters and couple them at any phase of the orbit. I will present the unprecedented precise synthetic emission spectra obtained with the upgraded 3D radiative transfer code Optim3D (Chiavassa et al. 2009), showing the impact that they have on the detection of a sample of molecules (e.g., CO, H2O, CO2, CH4) for a grid of mock observations (Maimone&Chiavassa, in prep.). This approach is expected to be particularly advantageous to improve the detectability of those molecules that are present in both the atmospheres and form in the same region of the spectrum, resulting in mixed and overlapped spectral lines.

Published
2022

11. I3T: Intensity Interferometry Imaging Telescope

Author

Adrien Vakili, Andrea Chiavassa, Mathilde Hugbart, F. Vakili, Robin Kaiser, William Guerin, J. P. Rivet, Pierre-Marie Gori, Guillaume Labeyrie, Laboratoire Lagrange, Université Côte d'Azur, Observatoire de la Côte d'Azur, CNRS., Shahid Beheshti University, Institut de Physique de Nice (INPHYNI), Centre National de la Recherche Scientifique (CNRS)-Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA), and University of Copenhagen = Københavns Universitet (KU)

Subjects
Diffraction, Astrophysics::High Energy Astrophysical Phenomena, Aperture synthesis, interferometers [instrumentation], FOS: Physical sciences, Physics::Optics, 01 natural sciences, Optical telescope, law.invention, Telescope, Optics, law, 0103 physical sciences, Instrumentation and Methods for Astrophysics (astro-ph.IM), 010303 astronomy & astrophysics, Cherenkov radiation, Physics, 010308 nuclear & particles physics, business.industry, Astrophysics::Instrumentation and Methods for Astrophysics, telescopes, Astronomy and Astrophysics, imaging [stars], [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], Interferometry, Space and Planetary Science, Limiting magnitude, Photonics, Astrophysics - Instrumentation and Methods for Astrophysics, business, high angular resolution [instrumentation]
Abstract

We propose a new approach, based on the Hanbury Brown and Twiss intensity interferometry, to transform a Cherenkov telescope to its equivalent optical telescope. We show that, based on the use of photonics components borrowed from quantum-optical applications, we can recover spatial details of the observed source down to the diffraction limit of the Cherenkov telescope, set by its diameter at the mean wavelength of observation. For this, we propose to apply aperture synthesis techniques from pairwise and triple correlation of sub-pupil intensities, in order to reconstruct the image of a celestial source from its Fourier moduli and phase information, despite atmospheric turbulence. We examine the sensitivity of the method, i.e. limiting magnitude, and its implementation on existing or future high energy arrays of Cherenkov telescopes. We show that despite its poor optical quality compared to extremely large optical telescopes under construction, a Cherenkov telescope can provide diffraction limited imaging of celestial sources, in particular at the visible, down to violet wavelengths., 8 pages, 7 figures

Published
2021

12. Gaia Early Data Release 3 The Gaia Catalogue of Nearby Stars

Author

Zoltan Balog, G. Tauran, Vincenzo Ripepi, Gerry Gilmore, M. Barros, Łukasz Wyrzykowski, Alberto Cellino, E. Poggio, P. Gavras, Simchon Faigler, Marc Audard, C. Nicolas, M. Vaillant, A. Mora, Paolo Tanga, Silvio Leccia, Despina Hatzidimitriou, A. Dapergolas, Eva Sciacca, Alberto Krone-Martins, N. Cheek, M. Hauser, Ulrike Heiter, S. Managau, L. Rohrbasser, Mathias Schultheis, E. Utrilla, Minia Manteiga, Marcella Marconi, Xavier Luri, F. De Angeli, Shay Zucker, Paolo Giacobbe, J. Juaristi Campillo, H. I. Siddiqui, J. Torra, F. X. Pineau, Roy Gomel, Thierry Morel, T. Cornez, Eric Gosset, Mario Gai, Jose M Hernandez, G. Giuffrida, A. de Torres, Laszlo Szabados, S. Ragaini, E. van Dillen, D. Semeux, Leanne P. Guy, R. Drimmel, L. M. Sarro, S. Voutsinas, Johannes Sahlmann, Damien Ségransan, S. Liao, Derek W. Morris, Jan Rybizki, André Moitinho, T. Roegiers, Bengt Edvardsson, Tristan Cantat-Gaudin, Martin Altmann, C. Turon, Laurent Chemin, K. Janßen, D. Garabato, Alejandra Recio-Blanco, Michał Pawlak, Lorenzo Rimoldini, Sergei A. Klioner, F. Torra, Carine Babusiaux, Alfred Castro-Ginard, G. Plum, Mariateresa Crosta, Iain A. Steele, A. Yoldas, Alex Lobel, J.-L. Bassilana, Harry Enke, Rosanna Sordo, Francesca Fragkoudi, F. De Luise, M. Bernet, Alessandro Sozzetti, M. Kontizas, Roberto Molinaro, C. Diener, S. Regibo, D. Barbato, T. Pauwels, R. E. de Souza, C. Fabricius, D. Souami, L. Martin Polo, M. Ramos-Lerate, Douglas J. Marshall, A. G. Butkevich, P. Madrero Pardo, P. Re Fiorentin, J. F. Le Campion, Jérôme Berthier, N. Tonello, Ummi Abbas, Y. Lebreton, M. Biermann, D. Munoz, N. Brouillet, David Teyssier, O. Vanel, P. A. Palicio, A. Jean-Antoine Piccolo, A. F. Lanza, Jesus Salgado, E. del Pozo, Antti Penttilä, R. Geyer, Ramachrisna Teixeira, L. Chaoul, Mike Smith, Rossella Cancelliere, J. M. Martín-Fleitas, D. Baines, M. Romero-Gómez, E. Anglada Varela, E. Livanou, X. Peñalosa Esteller, S. Diakite, Alberto Vecchiato, Thomas Wevers, Daniel Hestroffer, Sebastian L. Hidalgo, M. David, Angela Bragaglia, J. De Ridder, Mark Taylor, Roberto Morbidelli, A. Sagristà Sellés, Nigel Hambly, Arnaud Siebert, R. L. Smart, P. Burgess, Y. Le Fustec, Alessandro Bressan, H. Steidelmüller, Alberto Riva, H. E. Huckle, Morgan Fouesneau, N. Bauchet, P. Osborne, S. Marinoni, Krzysztof A. Rybicki, A. Masip, Laia Casamiquela, R. Messineo, A. Garofalo, Antonella Vallenari, R. Mor, Sahar Shahaf, P. de Laverny, G. Sadowski, Peter G. Jonker, A. Kochoska, F. Taris, A. F. Mulone, M. Ajaj, C. Ducourant, T. A. Lister, F. A. Jansen, Ruth Carballo, J. M. Carrasco, Tatiana Muraveva, W. van Reeven, P. Sartoretti, Jordi Portell, Andreas Korn, E. Salguero, Ana Ulla, P. Di Matteo, Coryn A. L. Bailer-Jones, J. Bakker, F. Riclet, G. Altavilla, Ulrich Bastian, P. Esquej, R. Buzzi, M. Segol, A. C. Lanzafame, L. Balaguer-Núñez, Beatrice Bucciarelli, C. Panem, E. Balbinot, T. Carlucci, Davide Massari, P. de Teodoro, Sébastien Lambert, M. I. Carnerero, Amina Helmi, F. Solitro, C. Robin, Carlos Dafonte, Tsevi Mazeh, A. Panahi, C. Fabre, Sergi Blanco-Cuaresma, Deborah Busonero, Maroussia Roelens, O. Marchal, Tomaz Zwitter, B. Holl, G. Holland, William Thuillot, Michael Davidson, E. Licata, Michele Bellazzini, Teresa Antoja, E. Szegedi-Elek, Francesca Figueras, Eric Slezak, Sergio Messina, N. Samaras, E. Poujoulet, Mark Cropper, A. Burlacu, R. Blomme, Elmé Breedt, Annie C. Robin, H. E. Delgado, Z. Kostrzewa-Rutkowska, Georges Kordopatis, Conny Aerts, L. Noval, Daniel Michalik, P. J. Richards, L. Karbevska, Grigori Fedorets, Maria Süveges, F. Crifo, J. Guiraud, D. Eappachen, K. Kruszyńska, Gisella Clementini, P. Yvard, Carme Jordi, L. Bramante, G. Busso, P. David, E. Fraile, Ugo Becciani, A. Lorca, Sanjeev Khanna, Alex Bombrun, Isabella Pagano, C. Dolding, A. M. Piersimoni, Paolo Montegriffo, A. Abreu Aramburu, Anthony G. A. Brown, Simon Hodgkin, Ennio Poretti, M. Fabrizio, I. Gonzalez-Santamaria, N. A. Walton, P. Panuzzo, Benoit Carry, Raphael Guerra, J. J. González-Vidal, T. Lebzelter, Nami Mowlavi, C. Barache, M. M. S. Marcos Santos, S. Cowell, Marco Castellani, J. J. Aguado, N. R. Millar, A. Baudesson-Stella, N. Leclerc, S. Bartolomé, J. Álvarez Cid-Fuentes, F. van Leeuwen, S. Bouquillon, Uwe Lammers, D. W. Evans, L. Eyer, M. van Leeuwen, A. Guerrier, J. González-Núñez, H. E. P. Lindstrøm, Miguel García-Torres, Ilaria Musella, L. Palaversa, W. Roux, W. Löffler, J.-B. Delisle, Dimitri Pourbaix, Timo Prusti, J. Osinde, M. Riello, G. Orrù, C. Crowley, Alessandra Mastrobuono-Battisti, Hector Canovas, D. L. Harrison, Y. Lasne, E. F. del Peloso, Laurent Galluccio, N. Hładczuk, T. Boch, Martin A. Barstow, László Molnár, Aldo Dell'Oro, C. Pagani, Krzysztof Nienartowicz, Stefano Bertone, Patrick Charlot, Eduard Masana, Elisabetta Caffau, N. Robichon, Luciana Bianchi, Federica Spoto, Felix Franke, J. L. Halbwachs, R. Gutiérrez-Sánchez, L. Pulone, Yassine Damerdji, Frédéric Arenou, Richard I. Anderson, Elena Pancino, David Hobbs, P. Castro Sampol, Yves Fremat, Pierre Kervella, C. Zurbach, Sofia Randich, Robert G. Mann, J. C. Segovia, Diego Bossini, D. Katz, Nicholas Rowell, P. Ramos, E. Racero, G. Gracia-Abril, R. Santoveña, R. Haigron, N. Unger, Enrique Solano, S. G. Baker, W. J. Cooper, F. Royer, S. Accart, George M. Seabroke, João Alves, Emese Plachy, Thomas Hilger, Pedro García-Lario, Gérard Jasniewicz, Kevin Benson, Christos Siopis, J. Souchay, Agnes Fienga, Giovanni Comoretto, F. Julbe, A. Hutton, Pierre Fernique, Céline Reylé, F. Pailler, Stefan Jordan, J. H. J. de Bruijne, C. A. Stephenson, E. Gerlach, Elisa Distefano, Karri Muinonen, Y. Viala, H. Zhao, L. Siltala, C. P. Murphy, Maria-Rosa L. Cioni, Andrea Chiavassa, D. Molina, J. Fernández-Hernández, G. Jevardat de Fombelle, Federico Marocco, Nicoletta Sanna, Alexey Mints, Juan Zorec, Ángel Gómez, I. Bellas-Velidis, M. G. Lattanzi, C. M. Raiteri, E. Brugaletta, Mikael Granvik, O. L. Creevey, Guy Rixon, Francois Mignard, P. M. Marrese, M. A. Álvarez, Caroline Soubiran, Rene Andrae, C. Ordénovic, A. Delgado, V. Sanchez Gimenez, J. Castañeda, D. Vicente, R. De March, A. Garcia-Gutierrez, M. Weiler, F. Thévenin, Lennart Lindegren, Isabelle Lecoeur-Taïbi, Jon Marchant, Monica Rainer, Alessandro Spagna, Andrej Prsa, M. Sarasso, Nicolas Rambaux, Paul J. McMillan, Ludovic Delchambre, M. Garcia-Reinaldos, M. Haywood, C. Fouron, S. Girona, Ministerio de Economía y Competitividad (España), Ministerio de Ciencia, Innovación y Universidades (España), Universidad de Barcelona, Xunta de Galicia, Generalitat de Catalunya, INAF - Osservatorio Astrofisico di Torino (OATo), Istituto Nazionale di Astrofisica (INAF), Univers, Transport, Interfaces, Nanostructures, Atmosphère et environnement, Molécules (UMR 6213) (UTINAM), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA), Galaxies, Etoiles, Physique, Instrumentation (GEPI), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Joseph Louis LAGRANGE (LAGRANGE), Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Centre National d'Études Spatiales [Toulouse] (CNES), Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Astronomische Rechen-Institut [Heidelberg] (ARI), Zentrum für Astronomie der Universität Heidelberg (ZAH), Universität Heidelberg [Heidelberg]-Universität Heidelberg [Heidelberg], Systèmes de Référence Temps Espace (SYRTE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Observatoire astronomique de Strasbourg (ObAS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Mésocentre de calcul (MESOCENTRE), Université de Franche-Comté (UFC), Centre de Données Astronomiques de Strasbourg, Partenaires INRAE, Géoazur (GEOAZUR 7329), Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Centre National de la Recherche Scientifique (CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA), Laboratoire Univers et Particules de Montpellier (LUPM), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Montpellier 2 - Sciences et Techniques (UM2), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), THALES, Université de Namur [Namur] (UNamur), Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France, Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Universität Heidelberg [Heidelberg] = Heidelberg University-Universität Heidelberg [Heidelberg] = Heidelberg University, Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), THALES [France], Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Universidad de Cantabria, Gaia Collaboration, Planetary-system research, Department of Physics, Particle Physics and Astrophysics, Astronomy, and ITA

Subjects
trigonometric parallaxes, Solar neighborhood, Stars: luminosity function, mass function, Astronomy, Astrophysics, 01 natural sciences, luminosity function, mass function [Stars], Astronomi, astrofysik och kosmologi, luminosity: mass function [Stars], Astronomy, Astrophysics and Cosmology, MAIN-SEQUENCE, Hertzsprung-Russell-diagram, 010303 astronomy & astrophysics, Stars:low-mass brown-dwarfs, wide binaries, Physics, education.field_of_study, north galactic pole, Astrophysics::Instrumentation and Methods for Astrophysics, Astrometry, BROWN DWARF, Astrophysics - Solar and Stellar Astrophysics, mass function, NORTH GALACTIC POLE, Physical Sciences, symbols, CIRCULAR-VELOCITY CURVE, Halo, astro-ph.SR, Hertzsprung–Russell diagram, stars: luminosity function, astro-ph.GA, Posterior probability, Population, main-sequence, Luminosity-Function, FOS: Physical sciences, Mass-Function, Astronomy & Astrophysics, Computer Science::Digital Libraries, Photometry (optics), DWARF LUMINOSITY-FUNCTION, dwarf luminosity-function, sky-survey, symbols.namesake, Settore FIS/05 - Astronomia e Astrofisica, luminosity function [stars], low-mass [Stars], 0103 physical sciences, Stars: luminosity: mass function, Stars: low-mass, WHITE-DWARFS, education, Solar and Stellar Astrophysics (astro-ph.SR), brown dwarf, catalogs, astrometry, Hertzsprung-Russell and C-M diagrams, stars: low-mass, solar neighborhood, Astrophysics - Astrophysics of Galaxies, SKY-SURVEY, white-dwarfs, Science & Technology, 010308 nuclear & particles physics, Luminosity function, White dwarf, TRIGONOMETRIC PARALLAXES, Astronomy and Astrophysics, Low-mass, 115 Astronomy, Space science, WIDE BINARIES, Stars, Physics::History of Physics, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), solar-neighborhood, Catalogs, circular-velocity curve, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

Aims. We produce a clean and well-characterised catalogue of objects within 100 pc of the Sun from the Gaia Early Data Release 3. We characterise the catalogue through comparisons to the full data release, external catalogues, and simulations. We carry out a first analysis of the science that is possible with this sample to demonstrate its potential and best practices for its use., Methods. Theselection of objects within 100 pc from the full catalogue used selected training sets, machine-learning procedures, astrometric quantities, and solution quality indicators to determine a probability that the astrometric solution is reliable. The training set construction exploited the astrometric data, quality flags, and external photometry. For all candidates we calculated distance posterior probability densities using Bayesian procedures and mock catalogues to define priors. Any object with reliable astrometry and a non-zero probability of being within 100 pc is included in the catalogue., Results. We have produced a catalogue of 331 312 objects that we estimate contains at least 92% of stars of stellar type M9 within 100 pc of the Sun. We estimate that 9% of the stars in this catalogue probably lie outside 100 pc, but when the distance probability function is used, a correct treatment of this contamination is possible. We produced luminosity functions with a high signal-to-noise ratio for the main-sequence stars, giants, and white dwarfs. We examined in detail the Hyades cluster, the white dwarf population, and wide-binary systems and produced candidate lists for all three samples. We detected local manifestations of several streams, superclusters, and halo objects, in which we identified 12 members of Gaia Enceladus. We present the first direct parallaxes of five objects in multiple systems within 10 pc of the Sun., Conclusions. We provide the community with a large, well-characterised catalogue of objects in the solar neighbourhood. This is a primary benchmark for measuring and understanding fundamental parameters and descriptive functions in astronomy.

Published
2021

13. Atmospheric structure and dynamics of evolved massive stars. Thanks to 3D radiative hydrodynamical simulations of stellar convection

Author

Andrea Chiavassa

Subjects
Space and Planetary Science, Astronomy and Astrophysics
Abstract

Evolved massive stars are major cosmic engines, providing strong mechanical and radiative feedback on their host environment. They contribute to the enrichment of their environment through a strong stellar winds, still poorly understood. Wind physics across the life cycle of these stars is the key ingredient to accomplish a complete understanding of their evolution in the near and distant Universe. Nowadays, the development of the observational instruments is so advanced that the observations became very sensitive to the details of the stellar surface making possible to quantitatively study what happens on their surfaces and above where the stellar winds become dominant. Three-dimensional radiative hydrodynamics simulations of evolved stars are essential to a proper and quantitative analysis of these observations. This work presents how these simulations have been (and will be) crucial to prepare and interpret a multitude of observations and how they are important to achieve the knowledge of the mass-loss mechanism.

Published
2020

14. The SAPP pipeline for the determination of stellar abundances and atmospheric parameters of stars in the core program of the PLATO mission

Author

Denis Mourard, Maria Bergemann, Luca Casagrande, Kevin Belkacem, Regner Trampedach, Nicolas Nardetto, Daniel R. Reese, Carlos del Burgo, Marie-Jo Goupil, Victor Silva Aguirre, Andrea Chiavassa, Thierry Morel, Matthew Raymond Gent, Bertrand Plez, Douglas J. Marshall, Martin Asplund, Maria Tsantaki, Jonay I. González Hernández, Aldo Serenelli, Mikhail Kovalev, Luisa Fernanda Rodríguez Díaz, Lionel Bigot, Ulrike Heiter, Vardan Adibekyan, Szabolcs Mészáros, Jeffrey M. Gerber, Rhita-Maria Ouazzani, Thibault Merle, European Space Agency, Centre National D'Etudes Spatiales (France), German Research Foundation, University of Heidelberg, Ministerio de Ciencia, Innovación y Universidades (España), Agencia Estatal de Investigación (España), Swedish National Space Agency, Fundação para a Ciência e a Tecnologia (Portugal), Hungarian Academy of Sciences, European Commission, European Research Council, Agence Nationale de la Recherche (France), Max Planck Society, Ministero dell'Istruzione, dell'Università e della Ricerca, Max Planck Institute for Astronomy (MPIA), Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, and COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
solar-type [stars], Metallicity, fundamental parameters [stars], FOS: Physical sciences, Core sample, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Surveys, 01 natural sciences, Astronomical spectroscopy, Luminosity, Astronomi, astrofysik och kosmologi, surveys, 0103 physical sciences, Stars: solar-type, Astronomy, Astrophysics and Cosmology, Astrophysics::Solar and Stellar Astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, Stars: fundamental parameters, atmospheres [stars], Physics, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 010308 nuclear & particles physics, Stars: abundances, low-mass. Techniques: spectroscopic. Surveys, Astronomy and Astrophysics, Observable, Effective temperature, Surface gravity, abundances [stars], Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, Stars: atmospheres, Astrophysics - Instrumentation and Methods for Astrophysics, fundamental parameters
Abstract

We introduce the SAPP (Stellar Abundances and atmospheric Parameters Pipeline), the prototype of the code that will be used to determine parameters of stars observed within the core program of the PLATO space mission. The pipeline is based on the Bayesian inference and provides effective temperature, surface gravity, metallicity, chemical abundances, and luminosity. The code in its more general version has a much wider range of potential applications. It can also provide masses, ages, and radii of stars and can be used with stellar types not targeted by the PLATO core program, such as red giants. We validate the code on a set of 27 benchmark stars that includes 19 FGK-type dwarfs, 6 GK-type subgiants, and 2 red giants. Our results suggest that combining various observables is the optimal approach, as this allows the degeneracies between different parameters to be broken and yields more accurate values of stellar parameters and more realistic uncertainties. For the PLATO core sample, we obtain a typical uncertainty of 27 (syst.) ± 37 (stat.) K for Teff, 0.00 ± 0.01 dex for log g, 0.02 ± 0.02 dex for metallicity [Fe/H], −0.01 ± 0.03 R⊙ for radii, −0.01 ± 0.05 M⊙ for stellar masses, and −0.14 ± 0.63 Gyr for ages. We also show that the best results are obtained by combining the νmax scaling relation with stellar spectra. This resolves the notorious problem of degeneracies, which is particularly important for F-type stars., This work presents results from the European Space Agency (ESA) space mission PLATO. The PLATO payload, the PLATO Ground Segment and PLATO data processing are joint developments of ESA and the PLATO Mission Consortium (PMC). Funding for the PMC is provided at national levels, in particular by countries participating in the PLATO Multilateral Agreement (Austria, Belgium, Czech Republic, Denmark, France, Germany, Italy, Netherlands, Portugal, Spain, Sweden, Switzerland, Norway, and United Kingdom) and institutions from Brazil. Members of the PLATO Consortium can be found at https://platomission.com. The ESA PLATO mission website is https://www.cosmos.esa.int/plato. We thank the teams working for PLATO for all their work. We thank P.E. Nissen for providing the reduced spectra of the Kepler legacy stars. M.R.G., M.B., J.G., and M.K. are supported by the Lise Meitner grant from the Max Planck Society. B.P. is partially supported by CNES, the Centre National d’Études Spatiales. We acknowledge support by the Collaborative Research centre SFB 881 (projects A5, A10), Heidelberg University, of the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation). We thank C. Aerts for providing helpful comments to this study. This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, https://www.cosmos.esa.int/web/gaia/dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. A.S. acknowledges support from MICINN grant PID2019-108709GB-I00. T.M. acknowledges financial support from Belspo for contract PRODEX PLATO mission development. U.H. acknowledges support from the Swedish National Space Agency (SNSA/Rymdstyrelsen). S.M. has been supported by the János Bolyai Research Scholarship of the Hungarian Academy of Sciences, and by the ÚNKP-20-5 New National Excellence Program of the Ministry for Innovation and Technology. N.N. acknowledges Anthony Salsi for useful discussions. V.A. is supported by FCT – Fundação para a Ciência e Tecnologia (FCT) through national grants: UID/FIS/04434/2019; UIDB/04434/2020; UIDP/04434/2020. V.A. also acknowledges the support from FCT through Investigador FCT contract nr. IF/00650/2015/CP1273/CT0001. M.T. acknowledges the funding from MIUR Premiale 2016: MITIC. L.C. is the recipient of the ARC Future Fellowship FT160100402. M.B. is supported through the Lise Meitner grant from the Max Planck Society. We acknowledge support by the Collaborative Research centre SFB 881 (projects A5, A10), Heidelberg University, of the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation). This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (Grant agreement No. 949173).

Published
2022

15. Planet Formation Imager (PFI): Science Vision and Key Requirements

Author

Stefan Kraus, John D Monnier, Michael J Ireland, Gaspard Duchene, Catherine Espaillat, Sebastian Hoenig, Attila Juhasz, Chris Mordasini, Johan Olofsson, Claudia Paladini, Keivan Stassun, Neal Turner, Gautam Vasisht, Tim J Harries, Matthew R Bate, Jean-Francois Gonzalez, Alexis Matter, Zhaohuan Zhu, Olja Panic, Zsolt Regaly, Alessandro Morbidelli, Farzana Meru, Sebastian Wolf, John Ilee, Jean-Philippe Berger, Ming Zhao, Quentin Kral, Andreas Morlok, Amy Bonsor, David Ciardi, Stephen R Kane, Kaitlin Kratter, Greg Laughlin, Joshua Pepper, Sean N Raymond, Lucas Labadie, Richard P Nelson, Gerd Weigelt, Theo ten Brummelaar, Arnaud Pierens, Rene Oudmaijer, Wilhelm Kley, Benjamin Pope, Eric L N Jensen, Amelia Bayo, Michael Smith, Tabetha Boyajian, Luis Henry Quiroga-Nuñez, Rafael Millan-Gabet, Andrea Chiavassa, Alexandre Gallenne, Mark Reynolds, Willem-Jan de Wit, Markus Wittkowski, Florentin Millour, Poshak Gandhi, Cristina Ramos Almeida, Almudena Alonso Herrero, Chris Packham, Makoto Kishimoto, Konrad R W Tristram, Jorg-Uwe Pott, Jean Surdej, David Buscher, Chris Haniff, Sylvestre Lacour, Romain Petrov, Steve Ridgway, Peter Tuthill, Gerard van Belle, Phil Armitage, Clement Baruteau, Myriam Benisty, Bertram Bitsch, Sijme-Jan Paardekooper, Christophe Pinte, Frederic Masset, and Giovanni P Rosotti

Subjects
Lunar and Planetary Science and Exploration
Abstract

The Planet Formation Imager (PFI) project aims to provide a strong scientific vision for ground-based optical astronomy beyond the upcoming generation of Extremely Large Telescopes. We make the case that a breakthrough in angular resolution imaging capabilities is required in order to unravel the processes involved in planet formation. PFI will be optimised to provide a complete census of the protoplanet population at all stellocentric radii and over the age range from 0.1 to ~ 100 Myr. Within this age period, planetary systems undergo dramatic changes and the final architecture of planetary systems is determined. Our goal is to study the planetary birth on the natural spatial scale where the material is assembled, which is the “Hill Sphere” of the forming planet, and to characterise the protoplanetary cores by measuring their masses and physical properties. Our science working group has investigated the observational characteristics of these young protoplanets as well as the migration mechanisms that might alter the system architecture. We simulated the imprints that the planets leave in the disk and study how PFI could revolutionise areas ranging from exoplanet to extragalactic science. In this contribution we outline the key science drivers of PFI and discuss the requirements that will guide the technology choices, the site selection, and potential science/technology tradeoffs.

Published
2016
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16. Presence of water on exomoons orbiting free-floating planets: a case study

Author

Stefano Bovino, Patricio Javier Ávila, E. Simoncini, Barbara Ercolano, Sebastian O. Danielache, Andrea Chiavassa, Tommaso Grassi, Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, and COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Astrochemistry, 010504 meteorology & atmospheric sciences, Physics and Astronomy (miscellaneous), Brown dwarf, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Cosmic ray, 01 natural sciences, 7. Clean energy, Astrobiology, Atmosphere, Planet, Ionization, 0103 physical sciences, Earth and Planetary Sciences (miscellaneous), 010303 astronomy & astrophysics, Ecology, Evolution, Behavior and Systematics, 0105 earth and related environmental sciences, Physics, Orbital elements, Earth and Planetary Astrophysics (astro-ph.EP), Exomoon, 13. Climate action, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

A free-floating planet is a planetary-mass object that orbits around a non-stellar massive object (e.g. a brown dwarf) or around the Galactic Center. The presence of exomoons orbiting free-floating planets has been theoretically predicted by several models. Under specific conditions, these moons are able to retain an atmosphere capable of ensuring the long-term thermal stability of liquid water on their surface. We model this environment with a one-dimensional radiative-convective code coupled to a gas-phase chemical network including cosmic rays and ion-neutral reactions. We find that, under specific conditions and assuming stable orbital parameters over time, liquid water can be formed on the surface of the exomoon. The final amount of water for an Earth-mass exomonoon is smaller than the amount of water in Earth oceans, but enough to host the potential development of primordial life. The chemical equilibrium time-scale is controlled by cosmic rays, the main ionization driver in our model of the exomoon atmosphere., Comment: 12 pages, 6 figures

Published
2021

17. Estimations of the muon content of cosmic ray air showers between 10 PeV and 1 EeV from KASCADE-Grande data

Author

R. Glasstetter, H. Bozdog, Kai Daumiller, E. Cantoni, Frank Schroeder, T. Pierog, A. Weindl, H.J. Mayer, Andrea Chiavassa, Markus Roth, D. Rivera-Rangel, R. Engel, M. E. Bertaina, J. Milke, K. Link, D. Kang, H.O. Klages, Alexandru Gherghel-Lascu, J. Oehlschlaeger, K. H. Kampert, A. Haungs, V. de Souza, G. Toma, W. D. Apel, G. C. Trinchero, F. Cossavella, J. R. Hoerandel, J. Zabierowski, Claus Grupen, P. Doll, T. Huege, H. J. Mathes, F. Di Pierro, D. Fuhrmann, H.J. Gils, S. Schoo, H. Rebel, H. Schieler, P. Luczak, S. Ostapchenko, K. Bekk, J. C. Arteaga-Velázquez, J. Bluemer, C. Morello, H. Ulrich, J. Wochele, Octavian Sima, D. Heck, and Juan Carlos Arteaga Velazquez

Subjects
Physics, Pierre Auger Observatory, Muon, Physics::Instrumentation and Detectors, Astronomy, Astrophysics::High Energy Astrophysical Phenomena, Hadron, Astrophysics::Instrumentation and Methods for Astrophysics, Attenuation length, Flux, Cosmic ray, Nuclear physics, KASCADE, High Energy Physics::Experiment, Zenith
Abstract

Measurements of KASCADE-Grande on the muon size in high energy extensive air showers (EAS) have provided evidence that the actual attenuation length of shower muons in the atmosphere is larger than the expectations from the hadronic interaction models QGSJET-II-04, EPOS-LHC and SIBYLL 2.3. This discrepancy is related with a deficient description of the shower muon content with atmospheric depth by MC models. To further explore the origin of the above anomaly, we have investigated the muon size as a function of the primary energy at different zenith angles using data from the KASCADE-Grande experiment. The procedure consisted in comparing the measured muon number flux against the predictions of a reference cosmic ray energy spectrum and from the observed difference to estimate the data/MC muon ratio that best describe the measurements. The ratio is then applied to the MC simulations and from here, we estimate the wanted muon content versus the primary energy. As a reference model, we employed the energy spectrum measured from the Pierre Auger observatory, while, for the different cosmic ray abundances, the GSF model. Results are presented using the QGSJET-II-04, EPOS-LHC, SIBYLL 2.3 and SIBYLL 2.3c models in the analysis procedure.

Published
2021

18. Astronomie et Astrophysique

Author

Rachael M. Roettenbacher, Fabien Baron, Norman Vargas, John B. Lester, Judit Sturmann, Arturo O. Martinez, Olli Majoinen, Chris Farrington, Ettore Pedretti, Nicholas J. Scott, Hilding R. Neilson, Claudia Paladini, T. ten Brummelaar, Miguel Montargès, Gail H. Schaefer, Stephen T. Ridgway, Nathalie D. Thureau, Douglas R. Gies, Xiao Che, Ryan P. Norris, Andrea Chiavassa, Matthew D. Anderson, John D. Monnier, Michael S. Connelley, Laszlo Sturmann, László L. Kiss, Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and Chiavassa, Andrea

Subjects
Physics, 010308 nuclear & particles physics, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Star (game theory), Infrared telescope, Center (category theory), FOS: Physical sciences, Astronomy and Astrophysics, Radius, Astrophysics, 01 natural sciences, Spectral line, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, 0103 physical sciences, [SDU.ASTR.SR] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Red supergiant, Angular resolution, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Line (formation)
Abstract

We present H-band interferometric observations of the red supergiant (RSG) AZ Cyg made with the Michigan Infra-Red Combiner (MIRC) at the six-telescope Center for High Angular Resolution Astronomy (CHARA) Array. The observations span 5 years (2011-2016), offering insight into the short and long-term evolution of surface features on RSGs. Using a spectrum of AZ Cyg obtained with SpeX on the NASA InfraRed Telescope Facility (IRTF) and synthetic spectra calculated from spherical MARCS, spherical PHOENIX, and SAtlas model atmospheres, we derive $T_{\text{eff}}$ is between $3972 K$ and $4000 K$ and $\log~g$ between $-0.50$ and $0.00$, depending on the stellar model used. Using fits to the squared visibility and Gaia parallaxes we measure its average radius $R=911^{+57}_{-50}~R_{\odot}$. Reconstructions of the stellar surface using our model-independent imaging codes SQUEEZE and OITOOLS.jl show a complex surface with small bright features that appear to vary on a timescale of less than one year and larger features that persist for more than one year. 1D power spectra of these images suggest a characteristic size of $0.52-0.69~R_{\star}$ for the larger, long lived features. This is close to the values of $0.51-0.53~R_{\star}$ derived from 3D RHD models of stellar surfaces. We conclude that interferometric imaging of this star is in line with predictions of 3D RHD models but that short-term imaging is needed to more stringently test predictions of convection in RSGs., 31 pages, 8 tables, 14 figures, accepted to ApJ

Published
2021

19. Atmosphere of Betelgeuse before and during the Great Dimming event revealed by tomography

Author

B. Freytag, K. Kravchenko, Claudia Paladini, Thibault Merle, Andrea Chiavassa, Alain Jorissen, H. Van Winckel, Bertrand Plez, S. Van Eck, M. Montargès, Max Planck Institute for Extraterrestrial Physics (MPE), Max-Planck-Gesellschaft, Institut d'Astronomie et d'Astrophysique [Bruxelles] (IAA), Université libre de Bruxelles (ULB), Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, and COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Brightness, CLOSE CIRCUMSTELLAR ENVIRONMENT, Opacity, FOS: Physical sciences, ENVELOPE TOMOGRAPHY, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astronomy & Astrophysics, 01 natural sciences, Computer Science::Digital Libraries, LONG SECONDARY PERIODS, Atmosphere, formation [line], Apparent magnitude, Astronomi, astrofysik och kosmologi, VARIABLE-STARS, 0103 physical sciences, Astronomy, Astrophysics and Cosmology, Astrophysics::Solar and Stellar Astrophysics, Red supergiant, COOL GIANT, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, Betelgeuse, Physics, atmospheres [stars], Science & Technology, AGB STARS, RED SUPERGIANT STARS, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 010308 nuclear & particles physics, MARCS MODEL ATMOSPHERES, EFFECTIVE TEMPERATURE, Stellar atmosphere, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy and Astrophysics, supergiants, MASS-LOSS, Galaxy, Physics::History of Physics, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, radiative transfer, Physical Sciences, spectroscopic [techniques], Astrophysics::Earth and Planetary Astrophysics, Sciences exactes et naturelles
Abstract

Despite being the best studied red supergiant star in our Galaxy, the physics behind the photometric variability and mass loss of Betelgeuse is poorly understood. Moreover, recently the star has experienced an unusual fading with its visual magnitude reaching a historical minimum. We investigate the nature of this event with the help of a recently developed tomographic technique. Tomography allows us to probe different depths in the stellar atmosphere and to recover the corresponding disk-averaged velocity field. We apply the tomographic method to a few-year time-series high-resolution spectroscopic observations of Betelgeuse in order to relate its atmospheric dynamics to the photometric variability. Our results show that a sudden increase of the molecular opacity in the cooler upper atmosphere of Betelgeuse is likely the reason of the observed unusual decrease of the star's brightness., A&A Letters, accepted for publication

Published
2021

20. Mid-infrared circumstellar emission of the long-period Cepheid l Carinae resolved with VLTI/MATISSE

Author

M. Schuil, G. Zins, Y. Fantei, Udo Beckmann, Péter Ábrahám, Anthony Meilland, K. Shabun, Philippe Stee, Farrokh Vakili, Ronald Roelfsema, A. Böhm, Andrea Chiavassa, G. Niccolini, L. Labadie, L. Mosoni, M. Riquelme, Alexandre Gallenne, P. Antonelli, R. Frahm, J.-L. Lizon, Markus Schöller, Ralf-Rainer Rohloff, Florentin Millour, Jean-Michel Clausse, Udo Neumann, F. Wrhel, M. de Haan, J. Meisner, Leonard Burtscher, R. Huerta, F. Allouche, Luca Pasquini, E. Garces, Pierre Cruzalèbes, Nicolas Nardetto, S. Morel, Behnam Javanmardi, P. Bourget, L. Jochum, A. Ridinger, R. S. Le Poole, Th. Rivinius, Bruno Lopez, V. Hocdé, Marco Delbo, I. Percheron, P. Girard, J. C. González Herrera, M. Accardo, G. Bazin, Karl Heinz Hofmann, Laszlo Szabados, J. W. Isbell, Eric Pantin, Jaime Alonso, Josef Hron, D. Schertl, Eszter Pozna, L. Klarmann, Th. Henning, S. Rousseau, C. Connot, E. Nußbaum, Eddy Elswijk, Louise Breuval, Antoine Mérand, R. van Boekel, E. Kokoulina, Leander Mehrgan, József Varga, Roberto Abuter, Markus Wittkowski, T. Adler, E. Lagadec, Claudia Paladini, M. Heininger, F. Guitton, Nicolas Schuhler, W. Laun, Romain Petrov, A. Jaskó, S. Abadie, R. ter Horst, Stephane Lagarde, R. Brast, F. Y. J. Gonté, Norbert Hubin, William C. Danchi, V. Gámez Rosas, A. Soulain, Walter Jaffe, Pierre Kervella, W. Boland, Ramón Navarro, Michiel R. Hogerheijde, Julien Woillez, K. Meixner, Felix Bettonvil, S. Borgniet, J. Beltran, Uwe Graser, Ph. Berio, Ralf Klein, J. Idserda, M. Lopez, Klaus Meisenheimer, Andreas Glindemann, J.-U. Pott, H. Hanenburg, Lars Venema, Sylvie Robbe-Dubois, Alexis Matter, Tibor Agócs, R. Buter, M. Ebert, Carsten Dominik, P. Guajardo, Laurent Pallanca, A. Marcotto, R. Waters, A. Gabasch, R. Castillo, M. Lehmitz, Jean-Charles Augereau, Derek Ives, Yves Bresson, S. Kuindersma, A. Glazenborg, Claudia Cid, C. Stephan, Sebastian Wolf, L. Mohr, J. Kragt, Christoph Leinert, F. Rigal, N. Tromp, Xavier Haubois, N. Mauclert, Gerd Jakob, Gerd Weigelt, J. Vinther, A. Chelli, C. Bailet, Paul Bristow, A. Domiciano de Souza, T. Maurer, A. van Duin, Ralf Conzelmann, M. Mellein, G. Kroes, G. Yoffe, T. Phan Duc, Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Lagrange, Université Côte d'Azur, Observatoire de la Côte d'Azur, CNRS., European Southern Observatory (ESO), COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Radioastronomie (MPIFR), Max Planck Institute for Astronomy (MPIA), Leiden Observatory [Leiden], Universiteit Leiden [Leiden], Observatoire de la Côte d'Azur (OCA), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and Low Energy Astrophysics (API, FNWI)

Subjects
Infrared, Cepheid variable, Astronomy, Astrophysics - astrophysics of galaxies, Flux, FOS: Physical sciences, Context (language use), Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Astrophysics - solar and stellar astrophysics, 010309 optics, Spitzer Space Telescope, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Spectroscopy, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Research Programm of Institute for Mathematics, Astrophysics and Particle Physics, Stars: variables: Cepheids, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Astronomy and Astrophysics, Circumstellar matter, Infrared: stars, [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], Stars, Wavelength, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Instrumentation: interferometers, Astrophysics of Galaxies (astro-ph.GA), Stars: atmospheres, Astrophysics::Earth and Planetary Astrophysics
Abstract

The nature of circumstellar envelopes (CSE) around Cepheids is still a matter of debate. The physical origin of their infrared (IR) excess could be either a shell of ionized gas, or a dust envelope, or both. This study aims at constraining the geometry and the IR excess of the environment of the long-period Cepheid $\ell$ Car (P=35.5 days) at mid-IR wavelengths to understand its physical nature. We first use photometric observations in various bands and Spitzer Space Telescope spectroscopy to constrain the IR excess of $\ell$ Car. Then, we analyze the VLTI/MATISSE measurements at a specific phase of observation, in order to determine the flux contribution, the size and shape of the environment of the star in the L band. We finally test the hypothesis of a shell of ionized gas in order to model the IR excess. We report the first detection in the L band of a centro-symmetric extended emission around l Car, of about 1.7$R_\star$ in FWHM, producing an excess of about 7.0\% in this band. In the N band, there is no clear evidence for dust emission from VLTI/MATISSE correlated flux and Spitzer data. On the other side, the modeled shell of ionized gas implies a more compact CSE ($1.13\pm0.02\,R_\star$) and fainter (IR excess of 1\% in the L band). We provide new evidences for a compact CSE of $\ell$ Car and we demonstrate the capabilities of VLTI/MATISSE for determining common properties of CSEs. While the compact CSE of $\ell$ Car is probably of gaseous nature, the tested model of a shell of ionized gas is not able to simultaneously reproduce the IR excess and the interferometric observations. Further Galactic Cepheids observations with VLTI/MATISSE are necessary for determining the properties of CSEs, which may also depend on both the pulsation period and the evolutionary state of the stars., Comment: 13 pages, 8 figures, accepted in Astronomy and Astrophysics

Published
2021

21. The Galactic Anticentre

Author

Vincenzo Ripepi, A. de Torres, Annie C. Robin, Mariateresa Crosta, C. Diener, L. Noval, Daniel Michalik, P. J. Richards, L. Karbevska, K. Kruszyńska, E. Fraile, André Moitinho, Michał Pawlak, P. Panuzzo, M. Riello, Benoit Carry, A. Yoldas, Harry Enke, N. Tonello, P. Gavras, M. Vaillant, Rosanna Sordo, E. del Pozo, Lorenzo Rimoldini, M. Bernet, G. Orrù, W. van Reeven, J. M. Martín-Fleitas, S. Diakite, P. Burgess, P. Osborne, Derek W. Morris, M. I. Carnerero, Amina Helmi, Mike Smith, Iain A. Steele, Alessandro Sozzetti, M. Kontizas, A. Sagristà Sellés, Roberto Molinaro, B. Holl, D. Baines, D. Molina, J. Fernández-Hernández, S. Marinoni, Michele Bellazzini, Maria Süveges, Teresa Antoja, D. Barbato, Uwe Lammers, Isabella Pagano, Davide Massari, G. Plum, P. Ramos, G. Jevardat de Fombelle, M. Biermann, C. Crowley, Mathias Schultheis, D. W. Evans, P. A. Palicio, Paolo Montegriffo, Ramachrisna Teixeira, R. Blomme, Elmé Breedt, T. A. Lister, F. A. Jansen, Ruth Carballo, Marcella Marconi, A. Abreu Aramburu, J. M. Carrasco, F. Royer, S. Accart, A. Burlacu, S. Regibo, Andrej Prsa, M. Sarasso, Nicolas Rambaux, A. F. Mulone, Ana Ulla, Eric Gosset, Alessandra Mastrobuono-Battisti, George M. Seabroke, H. E. Delgado, Federico Marocco, C. Nicolas, T. Lebzelter, Nami Mowlavi, C. Barache, Nicoletta Sanna, G. Gracia-Abril, R. Santoveña, R. Haigron, N. Unger, Silvio Leccia, A. Jean-Antoine Piccolo, A. F. Lanza, Alberto Vecchiato, Thomas Wevers, F. Figueras, G. Busso, C. Fabre, P. Di Matteo, F. Riclet, F. Solitro, Eric Slezak, N. Samaras, João Alves, Emese Plachy, Timo Prusti, F. van Leeuwen, J. Osinde, O. Marchal, M. Ajaj, C. Ducourant, Tatiana Muraveva, Shay Zucker, H. Steidelmüller, Alberto Riva, D. Semeux, N. Cheek, Laurent Galluccio, Martin A. Barstow, Alex Bombrun, S. Liao, M. van Leeuwen, R. E. de Souza, P. de Laverny, T. Roegiers, Paul J. McMillan, G. Holland, Alexey Mints, G. Giuffrida, L. M. Sarro, Juan Zorec, G. Sadowski, P. Yvard, Carme Jordi, J. L. Halbwachs, Laurent Chemin, Ludovic Delchambre, M. Garcia-Reinaldos, Ugo Becciani, Diego Bossini, Ángel Gómez, Sergi Blanco-Cuaresma, Rossella Cancelliere, C. Fabricius, J. De Ridder, L. Eyer, L. Pulone, Simon Hodgkin, Ennio Poretti, F. De Angeli, M. Haywood, E. Anglada Varela, Antonella Vallenari, F. X. Pineau, D. Garabato, A. Guerrier, H. E. P. Lindstrøm, Thomas Hilger, I. Bellas-Velidis, Frédéric Arenou, Paolo Giacobbe, Ilaria Musella, Tristan Cantat-Gaudin, L. Palaversa, Pedro García-Lario, David Hobbs, C. Turon, E. Balbinot, P. de Teodoro, Sébastien Lambert, D. Katz, Angela Bragaglia, Anthony G. A. Brown, Paolo Tanga, P. Castro Sampol, J. C. Segovia, Alejandra Recio-Blanco, Yves Fremat, Jon Marchant, Jose M Hernandez, S. Ragaini, Sofia Randich, P. Re Fiorentin, J. F. Le Campion, Gisella Clementini, M. Segol, P. David, R. Drimmel, F. Crifo, J. Guiraud, M. David, R. L. Smart, M. Fabrizio, I. Gonzalez-Santamaria, D. Eappachen, M. G. Lattanzi, Miguel García-Torres, Andreas Korn, S. Voutsinas, László Molnár, Simchon Faigler, A. Mora, Nicholas Rowell, Antti Penttilä, R. Geyer, Sanjeev Khanna, Aldo Dell'Oro, H. E. Huckle, C. Dolding, N. Leclerc, Monica Rainer, R. Mor, J. Bakker, Maroussia Roelens, Douglas J. Marshall, A. G. Butkevich, Nigel Hambly, A. Masip, Laia Casamiquela, R. Messineo, Martin Altmann, A. M. Piersimoni, Alessandro Spagna, Gerry Gilmore, Stefano Bertone, Patrick Charlot, O. Vanel, Daniel Hestroffer, Marco Castellani, Sebastian L. Hidalgo, W. Roux, Łukasz Wyrzykowski, Krzysztof A. Rybicki, M. M. S. Marcos Santos, Raphael Guerra, Alberto Cellino, E. Poggio, Gérard Jasniewicz, J. J. González-Vidal, S. Cowell, Peter G. Jonker, C. M. Raiteri, S. Bartolomé, J. Álvarez Cid-Fuentes, Elisabetta Caffau, J. J. Aguado, N. R. Millar, Ulrike Heiter, Federica Spoto, Felix Franke, A. Baudesson-Stella, M. Barros, Tsevi Mazeh, A. Panahi, E. Brugaletta, R. Buzzi, Elena Pancino, G. Altavilla, E. Racero, Enrique Solano, Mikael Granvik, Minia Manteiga, C. Robin, Tomaz Zwitter, Deborah Busonero, Alberto Krone-Martins, Marc Audard, Kevin Benson, Christos Siopis, L. Balaguer-Núñez, C. A. L. Bailer-Jones, E. Poujoulet, O. L. Creevey, E. Szegedi-Elek, C. Fouron, Michael Davidson, E. Licata, Despina Hatzidimitriou, Mark Cropper, Z. Kostrzewa-Rutkowska, S. Managau, A. Dapergolas, Sergio Messina, Laszlo Szabados, H. I. Siddiqui, W. Löffler, Mario Gai, J.-B. Delisle, Leanne P. Guy, S. G. Baker, W. J. Cooper, Alfred Castro-Ginard, Conny Aerts, A. Lorca, Xavier Luri, Damien Ségransan, Grigori Fedorets, A. Garofalo, J. Juaristi Campillo, F. De Luise, F. Pailler, F. Taris, L. Bramante, Thierry Morel, T. Cornez, L. Martin Polo, M. Ramos-Lerate, Jordi Portell, E. Salguero, Sergei A. Klioner, K. Janßen, Ulrich Bastian, Stefan Jordan, P. Esquej, A. C. Lanzafame, Beatrice Bucciarelli, C. Panem, Y. Lebreton, Carlos Dafonte, S. Girona, D. Munoz, Dimitri Pourbaix, William Thuillot, J. H. J. de Bruijne, N. Brouillet, L. Chaoul, F. Torra, Alex Lobel, J.-L. Bassilana, Francesca Fragkoudi, M. Romero-Gómez, C. A. Stephenson, T. Pauwels, Eva Sciacca, Alessandro Bressan, Morgan Fouesneau, E. Livanou, E. Gerlach, X. Peñalosa Esteller, Roberto Morbidelli, L. Rohrbasser, Johannes Sahlmann, Elisa Distefano, P. Sartoretti, Karri Muinonen, Zoltan Balog, Y. Viala, J. Torra, H. Zhao, L. Siltala, G. Tauran, D. Souami, P. Madrero Pardo, David Teyssier, Jesus Salgado, J. Souchay, C. P. Murphy, Maria-Rosa L. Cioni, N. A. Walton, S. Bouquillon, Andrea Chiavassa, Agnes Fienga, Giovanni Comoretto, F. Julbe, A. Hutton, Yassine Damerdji, Richard I. Anderson, Pierre Fernique, Céline Reylé, M. Hauser, E. Utrilla, Pierre Kervella, C. Zurbach, Robert G. Mann, Ummi Abbas, Hector Canovas, D. L. Harrison, Y. Lasne, Mark Taylor, Y. Le Fustec, E. F. del Peloso, N. Bauchet, E. van Dillen, Jan Rybizki, N. Hładczuk, T. Boch, J. González-Núñez, Carine Babusiaux, C. Pagani, Krzysztof Nienartowicz, Eduard Masana, G. Kordopatis, N. Robichon, Luciana Bianchi, R. Gutiérrez-Sánchez, Arnaud Siebert, A. Kochoska, T. Carlucci, Jérôme Berthier, J. Castañeda, D. Vicente, R. De March, A. Garcia-Gutierrez, M. Weiler, F. Thévenin, Lennart Lindegren, Isabelle Lecoeur-Taïbi, Guy Rixon, Francois Mignard, P. M. Marrese, M. A. Álvarez, Caroline Soubiran, Rene Andrae, C. Ordénovic, A. Delgado, V. Sanchez Gimenez, Ministerio de Economía y Competitividad (España), Ministerio de Ciencia, Innovación y Universidades (España), Universidad de Barcelona, Xunta de Galicia, European Commission, Centros de Excelencia Severo Ochoa, BARCELONA SUPERCOMPUTING CENTER (BSC), SEV2015-0493, Krone Martins, A. [0000-0002-2308-6623], McMillan, P. [0000-0002-8861-2620], Carrasco Martínez, J. P. [0000-0002-3029-5853], Sozzetti, A. [0000-0002-7504-365X], Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MINECO/ICTI2013-2016/MDM-2014-0369, Centrode Excelencia Científica Instituto de Ciencias del Cosmos Universidad de Barcelona, MINECO/ICTI2013-2016/SEV2015-0493, Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP), Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), National Natural Science Foundation of China (NSFC), Estonian Ministry of Education and Research, Centre National D'Etudes Spatiales (CNES), Agence Nationale de la Recherche (ANR), Centre National de la Recherche Scientifique (CNRS), European Commission (EC), European Research Council (ERC), Institut des Sciences de l'Univers (INSU), Institut National Polytechnique (INP), Institut National de Physique nucleaire et de Physique des Particules (IN2P3), Deutsches Zentrum für Luft- und Raumfahrt (DLR), Hungarian Academy of Sciences, Hungarian National Research, Development, and Innovation Office (NKFIH), Science Foundation Ireland (SFI), Israel Science Foundation (ISF), Agenzia Spaziale Italiana (ASI), Italian Istituto Nazionale di Astrofisica (INAF), Netherlands Organisation for Scientific Research (NWO), Polish National Science Centre, Ministry of Science and Higher Education (MNiSW), Fundacao para a Ciencia e a Tecnologia (FCT), Slovenian Research Agency, Agencia Estatal de Investigación (AEI), Generalitat de Catalunya, United Kingdom Science and Technology Facilities Council (STFC), United Kingdom Space Agency (UKSA), Gaia Collaboration, Universidad de Cantabria, Astronomy, Kapteyn Astronomical Institute, Institut de Ciencies del Cosmos (ICCUB), Universitat de Barcelona (UB), Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Kapteyn Astronomical Institute [Groningen], University of Groningen [Groningen], INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), M2A 2021, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Planetary-system research, Department of Physics, Particle Physics and Astrophysics, Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), Université Nice Sophia Antipolis (... - 2019) (UNS), and Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
trigonometric parallaxes, SOLAR NEIGHBORHOOD, Astronomy, SAGITTARIUS DWARF GALAXY, Astrophysics, 01 natural sciences, sagittarius dwarf galaxy, 010303 astronomy & astrophysics, Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], solar neighborhood, Astrophysics::Instrumentation and Methods for Astrophysics, Astrometry, Gelexy: kinematics and dynamics, Kinematics and Dynamics, Open clusters and asssociations: individual: Berkeley 29, sky survey, Disk, Physical Sciences, kinematics and dynamics [Gelexy], old open clusters, MILKY-WAY, Astrophysics::Earth and Planetary Astrophysics, open clusters and associations: individual: Berkeley 29, Galaxy: kinematics and dynamics, disk [Galaxy], individual: Berkeley 29 [open clusters and associations], Astrometria, Berkeley 29, EXPLORING HALO SUBSTRUCTURE, LOCAL KINEMATICS, Milky Way, FOS: Physical sciences, Open Clusters and Associations, Individual, exploring halo substructure, Astrophysics::Cosmology and Extragalactic Astrophysics, Astronomy & Astrophysics, Computer Science::Digital Libraries, stellar structure, Galaxy: disk, Open clusters and associations: individual: Saurer 1, Galactic halo, Halo, Settore FIS/05 - Astronomia e Astrofisica, individual: Berkeley 29 [Open clusters and asssociations], 0103 physical sciences, distances [stars], halo [Galaxy], Disc, Stars: distances, milky-way, Saurer 1, Astrophysics::Galaxy Astrophysics, canis-major, Science & Technology, 010308 nuclear & particles physics, TRIGONOMETRIC PARALLAXES, Galaxy: halo, stars: distances, open clusters and associations: individual: Saurer 1, Astrophysics - Astrophysics of Galaxies, Astronomy and Astrophysics, Galactic plane, kinematics and dynamics [Galaxy], 115 Astronomy, Space science, CANIS-MAJOR, Stars, Galaxy, Physics::History of Physics, Estels, individual: Saurer 1 [open clusters and associations], Distances, local kinematics, OLD OPEN CLUSTERS, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), SKY SURVEY, Open cluster, STELLAR STRUCTURE
Abstract

Aims. We aim to demonstrate the scientific potential of the Gaia Early Data Release 3 (EDR3) for the study of different aspects of the Milky Way structure and evolution and we provide, at the same time, a description of several practical aspects of the data and examples of their usage., Methods. We used astrometric positions, proper motions, parallaxes, and photometry from EDR3 to select different populations and components and to calculate the distances and velocities in the direction of the anticentre. In this direction, the Gaia astrometric data alone enable the calculation of the vertical and azimuthal velocities; also, the extinction is relatively low compared to other directions in the Galactic plane. We then explore the disturbances of the current disc, the spatial and kinematical distributions of early accreted versus in situ stars, the structures in the outer parts of the disc, and the orbits of open clusters Berkeley 29 and Saurer 1., Results. With the improved astrometry and photometry of EDR3, we find that: (i) the dynamics of the Galactic disc are very complex with oscillations in the median rotation and vertical velocities as a function of radius, vertical asymmetries, and new correlations, including a bimodality with disc stars with large angular momentum moving vertically upwards from below the plane, and disc stars with slightly lower angular momentum moving preferentially downwards; (ii) we resolve the kinematic substructure (diagonal ridges) in the outer parts of the disc for the first time; (iii) the red sequence that has been associated with the proto-Galactic disc that was present at the time of the merger with Gaia-Enceladus-Sausage is currently radially concentrated up to around 14 kpc, while the blue sequence that has been associated with debris of the satellite extends beyond that; (iv) there are density structures in the outer disc, both above and below the plane, most probably related to Monoceros, the Anticentre Stream, and TriAnd, for which the Gaia data allow an exhaustive selection of candidate member stars and dynamical study; and (v) the open clusters Berkeley 29 and Saurer 1, despite being located at large distances from the Galactic centre, are on nearly circular disc-like orbits., Conclusions. Even with our simple preliminary exploration of the Gaia EDR3, we demonstrate how, once again, these data from the European Space Agency are crucial for our understanding of the different pieces of our Galaxy and their connection to its global structure and history.

Published
2021
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22. Gaia early data release 3: summary of the contents and survey properties (Corrigendum)

Author

Mathias Schultheis, Marcella Marconi, N. Robichon, Luciana Bianchi, F. Crifo, J. Guiraud, D. Eappachen, R. Gutiérrez-Sánchez, Sanjeev Khanna, A. M. Piersimoni, Raphael Guerra, J. J. González-Vidal, J. J. Aguado, N. R. Millar, A. Baudesson-Stella, Tristan Cantat-Gaudin, Alejandra Recio-Blanco, Ummi Abbas, Francesca Figueras, R. Blomme, Elmé Breedt, G. Busso, A. Jean-Antoine Piccolo, Gerry Gilmore, A. Panahi, S. Messina, C. Babusiaux, Łukasz Wyrzykowski, Mark Taylor, Alex Bombrun, M. Barros, M. Riello, M. Ajaj, C. Ducourant, Tatiana Muraveva, Alberto Cellino, E. Poggio, Y. Le Fustec, C. P. Murphy, Maria-Rosa L. Cioni, Hector Canovas, D. L. Harrison, Y. Lasne, Elena Pancino, N. Bauchet, G. Orrù, Sergi Blanco-Cuaresma, Simon Hodgkin, Ennio Poretti, A. F. Lanza, Alberto Vecchiato, Thomas Wevers, Andrea Chiavassa, E. Szegedi-Elek, A. G. A. Brown, Laszlo Szabados, A. Masip, Laia Casamiquela, R. Messineo, C. Crowley, Alessandra Mastrobuono-Battisti, E. Poujoulet, Zoltan Balog, L. Eyer, A. Guerrier, H. E. P. Lindstrøm, Ilaria Musella, Laurent Galluccio, Martin A. Barstow, Aldo Dell'Oro, Mark Cropper, Z. Kostrzewa-Rutkowska, Angela Bragaglia, Arnaud Siebert, Damien Ségransan, A. Kochoska, J. L. Halbwachs, E. F. del Peloso, N. Hładczuk, F. Pailler, Stefan Jordan, Stefano Bertone, L. Pulone, Frédéric Arenou, Patrick Charlot, David Hobbs, P. Castro Sampol, Yves Fremat, Sofia Randich, Marc Audard, Despina Hatzidimitriou, A. Dapergolas, L. Palaversa, W. van Reeven, M. Hauser, E. Utrilla, Georges Kordopatis, Sergei A. Klioner, Alex Lobel, J.-L. Bassilana, G. Tauran, T. Prusti, H. Steidelmüller, Alberto Riva, Diego Bossini, Maria Süveges, Isabella Pagano, J. H. J. de Bruijne, Elisabetta Caffau, Federica Spoto, Felix Franke, T. Boch, M. I. Carnerero, T. Carlucci, Grigori Fedorets, J. Castañeda, W. Löffler, Enrique Solano, Paolo Montegriffo, A. Abreu Aramburu, T. Lebzelter, Nami Mowlavi, C. Barache, C. A. Stephenson, A. Lorca, L. Bramante, Amina Helmi, J.-B. Delisle, B. Holl, D. Molina, J. Fernández-Hernández, G. Jevardat de Fombelle, F. van Leeuwen, C. Robin, D. Katz, E. Gerlach, Elisa Distefano, Michele Bellazzini, P. de Laverny, G. Sadowski, Tomaz Zwitter, A. Burlacu, Teresa Antoja, Rossella Cancelliere, F. Torra, C. Pagani, Annie C. Robin, Johannes Sahlmann, Karri Muinonen, Eva Sciacca, D. Vicente, Krzysztof Nienartowicz, A. F. Mulone, Shay Zucker, Nicholas Rowell, H. E. Delgado, Dimitri Pourbaix, G. Giuffrida, H. E. Huckle, Federico Marocco, L. Noval, Daniel Michalik, P. J. Richards, Y. Viala, E. van Dillen, L. Karbevska, H. Zhao, L. Siltala, Nicoletta Sanna, K. Kruszyńska, E. Fraile, R. De March, Y. Lebreton, C. M. Raiteri, D. W. Evans, Ana Ulla, Francesca Fragkoudi, Jan Rybizki, E. Brugaletta, L. Rohrbasser, Andreas Korn, S. G. Baker, A. Garcia-Gutierrez, L. M. Sarro, R. Buzzi, T. Pauwels, Jérôme Berthier, L. Chaoul, W. J. Cooper, Eduard Masana, M. van Leeuwen, D. Garabato, P. Panuzzo, Maroussia Roelens, Benoit Carry, Deborah Busonero, Michael Davidson, J. González-Núñez, Thomas Hilger, E. Licata, M. Weiler, Mikael Granvik, Alessandro Bressan, Morgan Fouesneau, Miguel García-Torres, W. Roux, Pedro García-Lario, Iain A. Steele, P. Ramos, Alessandro Sozzetti, Roberto Molinaro, O. L. Creevey, D. Barbato, Lorenzo Rimoldini, Uwe Lammers, Alexey Mints, P. Sartoretti, E. Livanou, D. Souami, P. Madrero Pardo, David Teyssier, M. Bernet, Yassine Damerdji, X. Peñalosa Esteller, C. Fabre, F. Thévenin, Gérard Jasniewicz, Roberto Morbidelli, Jesus Salgado, Juan Zorec, Ángel Gómez, Douglas J. Marshall, A. G. Butkevich, M. Biermann, E. Racero, J. Torra, R. Gomel, O. Vanel, Daniel Hestroffer, Sebastian L. Hidalgo, P. A. Palicio, F. De Angeli, Richard L. Smart, J. M. Martín-Fleitas, Derek W. Morris, F. Royer, S. Diakite, S. Accart, C. Dolding, P. Burgess, Richard I. Anderson, A. Garofalo, I. Bellas-Velidis, George M. Seabroke, P. Osborne, Claus Fabricius, Jon Marchant, Ramachrisna Teixeira, João Alves, G. Gracia-Abril, R. Santoveña, R. Haigron, N. Unger, Lennart Lindegren, Isabelle Lecoeur-Taïbi, Paolo Giacobbe, Emese Plachy, M. Fabrizio, I. Gonzalez-Santamaria, F. Taris, Kevin Benson, Christos Siopis, M. M. S. Marcos Santos, S. Cowell, Jose M Hernandez, S. Ragaini, Jordi Portell, Linda K. Molnar, R. Drimmel, Pierre Kervella, C. Zurbach, S. Bartolomé, J. Álvarez Cid-Fuentes, E. Salguero, Ulrich Bastian, Robert G. Mann, Marco Castellani, J. Osinde, E. Balbinot, Caroline Soubiran, Rene Andrae, J. Souchay, M. G. Lattanzi, S. Voutsinas, Agnes Fienga, Giovanni Comoretto, P. Esquej, A. C. Lanzafame, Beatrice Bucciarelli, C. Panem, Carlos Dafonte, Alfred Castro-Ginard, J. C. Segovia, Monica Rainer, F. Julbe, A. Hutton, Peter G. Jonker, William Thuillot, A. de Torres, F. De Luise, Pierre Fernique, Céline Reylé, M. Kontizas, G. Plum, Martin Altmann, L. Martin Polo, M. Ramos-Lerate, P. de Teodoro, Sébastien Lambert, G. Altavilla, André Moitinho, D. Munoz, N. Brouillet, Alessandro Spagna, C. Ordénovic, Gisella Clementini, C. Nicolas, Michał Pawlak, Silvio Leccia, A. Delgado, M. Romero-Gómez, N. Cheek, A. Yoldas, Harry Enke, Rosanna Sordo, V. Sanchez Gimenez, Mike Smith, P. David, D. Baines, Paolo Tanga, Guy Rixon, Alberto Krone-Martins, S. Managau, N. A. Walton, S. Bouquillon, C. Fouron, Francois Mignard, Xavier Luri, J. Juaristi Campillo, S. Girona, Thierry Morel, T. Cornez, P. M. Marrese, M. A. Álvarez, S. Liao, Andrej Prsa, M. Sarasso, Nicolas Rambaux, Paul J. McMillan, Ludovic Delchambre, M. Garcia-Reinaldos, M. Haywood, E. Anglada Varela, Antonella Vallenari, S. Regibo, R. E. de Souza, Sahar Shahaf, J. De Ridder, M. Segol, Simchon Faigler, A. Mora, Ulrike Heiter, Carla Cacciari, Minia Manteiga, H. I. Siddiqui, Mario Gai, Leanne P. Guy, N. Leclerc, T. A. Lister, F. A. Jansen, Ruth Carballo, J. M. Carrasco, Bengt Edvardsson, P. Di Matteo, K. Janßen, F. Riclet, F. Solitro, O. Marchal, G. Holland, F. X. Pineau, C. Turon, P. Re Fiorentin, Tsevi Mazeh, Mariateresa Crosta, C. Diener, J. F. Le Campion, Vincenzo Ripepi, M. David, R. Mor, N. Tonello, E. del Pozo, J. Bakker, Davide Massari, A. Sagristà Sellés, Marco Delbo, Eric Slezak, P. Gavras, N. Samaras, S. Marinoni, M. Vaillant, J. M. Petit, P. Yvard, Carme Jordi, Ugo Becciani, Antti Penttilä, R. Geyer, Nigel Hambly, Krzysztof A. Rybicki, L. Balaguer-Núñez, C. A. L. Bailer-Jones, Conny Aerts, Eric Gosset, D. Semeux, T. Roegiers, and Laurent Chemin

Subjects
Physics, Addenda, 010504 meteorology & atmospheric sciences, Errata, Parallaxes, Astronomy, Astronomy and Astrophysics, Astrophysics, Astrometry, Photometric, 01 natural sciences, Techniques, catalogs, astrometry, parallaxes, proper motions, techniques: photometric, errata, addenda, Settore FIS/05 - Astronomia e Astrofisica, Space and Planetary Science, 0103 physical sciences, Proper motions, Catalogs, 010303 astronomy & astrophysics, Data release, 0105 earth and related environmental sciences
Abstract

We present the early installment of the third Gaia data release, Gaia EDR3, consisting of astrometry and photometry for 1.8 billion sources brighter than magnitude 21, complemented with the list of radial velocities from Gaia DR2. Gaia EDR3 contains celestial positions and the apparent brightness in G for approximately 1.8 billion sources. For 1.5 billion of those sources, parallaxes, proper motions, and the (G_BP-G_RP) colour are also available. The passbands for G, G_BP, and G_RP are provided as part of the release. For ease of use, the 7 million radial velocities from Gaia DR2 are included in this release, after the removal of a small number of spurious values. New radial velocities will appear as part of Gaia DR3. Finally, Gaia EDR3 represents an updated materialisation of the celestial reference frame (CRF) in the optical, the Gaia-CRF3, which is based solely on extragalactic sources. The creation of the source list for Gaia EDR3 includes enhancements that make it more robust with respect to high proper motion stars, and the disturbing effects of spurious and partially resolved sources. The source list is largely the same as that for Gaia DR2, but it does feature new sources and there are some notable changes. The source list will not change for Gaia DR3. Gaia EDR3 represents a significant advance over Gaia DR2, with parallax precisions increased by 30 percent, proper motion precisions increased by a factor of 2, and the systematic errors in the astrometry suppressed by 30--40 percent for the parallaxes and by a factor ~2.5 for the proper motions. The photometry also features increased precision, but above all much better homogeneity across colour, magnitude, and celestial position. A single passband for G, G_BP, and G_RP is valid over the entire magnitude and colour range, with no systematics above the 1 percent level.

Published
2021

23. A shortcut to calculate SPAM limb-darkening coefficients

Author

Andrea Chiavassa and Giuseppe Morello

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), Atmospheric models, FOS: Physical sciences, General Medicine, Light curve, Grid, Photometry (optics), Quadratic equation, Astrophysics - Solar and Stellar Astrophysics, Limb darkening, Applied mathematics, Astrophysics - Instrumentation and Methods for Astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), Solar and Stellar Astrophysics (astro-ph.SR), Mathematics, Astrophysics - Earth and Planetary Astrophysics
Abstract

We release a new grid of stellar limb-darkening coefficients (LDCs, using the quadratic, power-2 and claret-4 laws) and intensity profiles for the Kepler, U, B, V and R passbands, based on STAGGER model atmospheres. The data can be downloaded from Zenodo (doi:10.5281/zenodo.5593162). We compare the newly-released LDCs, computed by ExoTETHyS, with previously published values, based on the same atmospheric models using a so-called "SPAM" procedure. The SPAM method relies on synthetic light curves in order to compute the LDCs that best represent the photometry of exoplanetary transits. We confirm that ExoTETHyS achieves the same objective with a much simpler algorithm., Comment: Published: G. Morello and A. Chiavassa 2021, Res. Notes AAS, 5, 247

Published
2021
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24. Sensitivity of the Cherenkov Telescope Array for probing cosmology and fundamental physics with gamma-ray propagation

Author

J.-P. Lenain, A. Domínguez, Jonathan Ivor Davies, T. Armstrong, A. A. Zdziarski, F. Gianotti, M. Balbo, E. O. Angüner, M. Marculewicz, Alasdair E. Gent, Alice Donini, Olivier Hervet, Henry Przybilski, Giacomo Principe, G. Leto, M. Peresano, Stefano Covino, P. A. Caraveo, Gianpiero Tagliaferri, D. de Martino, V. V. Vassiliev, D. Cauz, F. R. Pantaleo, U. Barres de Almeida, Pietro Bruno, E. Lindfors, M. Zavrtanik, G. Hughes, Miriam Lucio Martinez, P. Bordas, Y. Suda, G. S. Varner, R. Rando, K. Cerny, S. Pita, Csaba Balázs, E. Fiandrini, Michael Backes, Tomohiko Oka, Massimo Persic, Andrea Chiavassa, Johannes Veh, A. Stamerra, Fabrizio Tavecchio, B. Biasuzzi, Michael Punch, Soebur Razzaque, F. D'Ammando, P. I. Batista, Bruna Bertucci, F. Longo, Francesco Gabriele Saturni, Michael G. Burton, Bohdan Hnatyk, P. Sangiorgi, E. M. Santos, D. Nosek, Gagik Tovmassian, J. L. Dournaux, Pedro L. Luque-Escamilla, A. Aguirre-Santaella, M. Orienti, Lluis Font, Andreas Quirrenbach, Philippe Laporte, Ralf Kissmann, Francesco Lucarelli, K. Noda, I. Jiménez Martínez, G. Romeo, Wystan Benbow, P. Romano, B. Bi, J. Grube, H.-S. Zechlin, Giacomo Bonnoli, Martin White, J. P. Osborne, Enrico Cascone, Marek Jamrozy, C. Alispach, Miroslav Pech, O. Cuevas, Petr Schovanek, K. Hayashi, V. I. Zhdanov, Javier Coronado-Blázquez, D. Medina Miranda, Barbara Balmaverde, E. de Ona Wilhelmi, Frank M. Rieger, A. Shalchi, J. M. Paredes, Ruben Alfaro, N. Giglietto, Diego Falceta-Gonçalves, Helene Sol, Rodolfo Carosi, Ayan Acharyya, Dominik Elsässer, S. Vercellone, D. Pimentel, T. Mizuno, Alessandro Bruno, Juan Abel Barrio, K. Kosack, Mauro Orlandini, Rodrigo Guedes Lang, P. Marquez, Adrian Biland, Y. Kobayashi, Nicholas F. H Tothill, M. de Naurois, Daniele Spiga, Lili Yang, L. Tibaldo, Pavel Horvath, M. Lopez, I. Sadeh, Marek Nikolajuk, F. Schüssler, Reshmi Mukherjee, Gianpaolo Vettolani, Jürgen Knödlseder, Daniel Nieto, R. Hnatyk, German Martinez, Diego F. Torres, Farinaldo S. Queiroz, N. Parmiggiani, G. Lamanna, Marcos Santander, S. Fegan, I. Vovk, M. Sánchez-Conde, Wiphu Rujopakarn, Norita Kawanaka, R. C. Shellard, Michael C. B. Ashley, J. Jurysek, Francisco J. Franco, Samuel Timothy Spencer, E. Rebert, J. Morales Merino, M. Pecimotika, Marco Berton, Regis Terrier, G. A. Beck, Carlos Díaz, J. L. Contreras, G. Zaharijas, R. Moderski, José-María Martí, A. Insolia, D. Zavrtanik, K. Kohri, Ladislav Chytka, T. Grabarczyk, A. Zech, M. Garczarczyk, Anastasia Sokolenko, J. Lefaucheur, R. A. Cameron, Moritz Hütten, S. Karkar, K. Pfrang, V. Poireau, Asaf Pe'er, A. Reimer, Fabio Acero, L. Freixas Coromina, David Sánchez, Jonathan S. Lapington, Konstantinos N. Gourgouliatos, J.R. Hörandel, Mario Buscemi, Francesco Dazzi, Abelardo Moralejo, J. Bolmont, R. White, A. Rosales de Leon, J. Prast, Sabrina Einecke, Roberto Aloisio, Yvonne Becherini, Andreas Specovius, Shohei Yanagita, Juan Cortina, Miroslav Hrabovsky, Petr Janecek, D. Depaoli, Lucas Taylor, U. Schwanke, H. Abdalla, S. Recchia, Manuela Mallamaci, M. K. Daniel, Q. Feng, L. Baroncelli, Hiromitsu Takahashi, Susumu Inoue, U. Straumann, Masatoshi Ohishi, Roberto Capuzzo-Dolcetta, Nu. Komin, Federico Russo, R. de Cássia dos Anjos, Y. Ohira, Ferdinando Giordano, Nagisa Hiroshima, E. Garcia, Gavin Rowell, V. Bozhilov, Maxim V. Barkov, Dario Hrupec, I. Oya, F. Salesa Greus, Anna Wolter, M. Živec, R. Belmont, R. Adam, T. Reposeur, J. Rico, A. W. Chen, G. Pühlhofer, H. Prokoph, Stefan Wagner, F. Di Pierro, Fabrizio Bocchino, M. de Bony de Lavergne, A. Kong, Masha Chernyakova, M. Pohl, M. Vazquez Acosta, A. Nagai, A. Brill, Dusan Mandat, Jonathan Biteau, Martin Makariev, Catherine Boisson, E. Lyard, Gilles Maurin, H. Martínez-Huerta, Oscar Blanch, Bernd Schleicher, M. Minev, A. Berti, James E. M. Watson, Talvikki Hovatta, M. Valentino, Luis Ángel Tejedor, Elena Amato, M. V. Fonseca, Anderson Caproni, L. Mohrmann, P. Reichherzer, R. L. C. Starling, M. Seglar Arroyo, E. Orlando, B. Rudak, G. Emery, J. A. Green, Salvo Scuderi, M. Prouza, Tom Richtler, Bartłomiej Pilszyk, A. Carosi, Jacek Niemiec, Wolfgang Rhode, G. Ambrosi, D. Ribeiro, A. Wierzcholska, A. Ghalumyan, Eugenio Bottacini, Sylvain Chaty, A. Baquero Larriva, Olaf Reimer, D. Horan, Fabian Leuschner, T. Di Girolamo, Alessandro Caccianiga, Martin Will, Saverio Lombardi, A. Fiasson, Mitsunari Takahashi, J. J. Rodríguez Vázquez, B. De Lotto, V. De Caprio, Stefano Truzzi, Dirk L. Hoffmann, M. Vecchi, Antonio Pagliaro, Jose J. Gonzalez, Wenwu Tian, R. Della Ceca, J. Becerra González, S. Nozaki, T. Vuillaume, S. L. Lloyd, Maria Ionica, Elisabetta Bissaldi, Petr Travnicek, Y. Ascasibar, Carlo Vigorito, F. Tuossenel, Malcolm Fairbairn, O. Martinez, Marco Iarlori, Serena Loporchio, Alessandro Costa, R. Pillera, A. Morselli, M. Heller, Jaime Rosado, E. M. de Gouveia Dal Pino, V. Vitale, A. M. Brown, E. Molina, Takashi Saito, A. De Angelis, Thomas Murach, R. A. Ong, J. Bregeon, P. T. O'Brien, Mikael Jacquemont, P. Cristofari, Francesco Conte, Lab Saha, R. Walter, Vitalii Sliusar, W. Jin, Vito Conforti, N. Produit, H. Siejkowski, Lovro Pavletić, Carole Mundell, G. Rodriguez Fernandez, J. F. Glicenstein, Paresh Sharma, C. Delgado, Vladimír Karas, Luca Foffano, J. Granot, Manuel Meyer, Reiko Orito, G. Umana, G. Chiaro, D. Tonev, R. Wiemann, G. Manicò, J.C. Rodriguez Ramirez, Luca Tosti, Markus Böttcher, Andrea Bulgarelli, C. Díaz-Bahamondes, I. Jung-Richardt, Karol Seweryn, P. Piatteli, Agnieszka Slowikowska, Jan Ebr, M. Ostrowski, J. L. Rodriguez, D. della Volpe, Ermanno Pietropaolo, M. Caprai, T. Montaruli, A. Lopez, Rodrigo Nemmen, R. R. Prado, L. Arrabito, Atreyee Sinha, C. van Eldik, Serguei Vorobiov, Hidetoshi Sano, J. Alfaro, Sabrina Casanova, G. Maneva, B. Vallage, Valentina Fioretti, Carmelo Evoli, P. Kaaret, B. A. W. Mode, Agnieszka Majczyna, Sebastian Diebold, A. Scherer, F. de Palma, S. Hernández Cadena, V. Beshley, T.R.N. Ekoume, David A. Williams, M. Capasso, A. Halim, Alison Mitchell, Tomislav Terzić, Paola Grandi, Lorenzo Amati, Christopher Eckner, David Gascon, K. Nishijima, J. Becker Tjus, B. Khélifi, G. Galanti, Jamie Holder, Vincenzo Rizi, Orel Gueta, Daniele Gaggero, F. Pintore, Utane Sawangwit, Vassil Verguilov, Heide Costantini, F. Arqueros, Daniel Kerszberg, P. M. Chadwick, D. Zarić, Marc Ribó, Olga Sergijenko, Dario Grasso, Hidetoshi Kubo, Daniela Dorner, T. Stolarczyk, M. Gaug, R. Alves Batista, Elisa Bernardini, Vikram V. Dwarkadas, Jim Hinton, Jelena Strišković, Andreu Sanuy, M. Servillat, V. Barbosa Martins, Giovanni Bonanno, S. Gunji, R. Wischnewski, S. Sarkar, Gianluca Giavitto, Takeshi Nakamori, M. Palatka, Maria Letizia Pumo, Camilla Maggio, M. Zacharias, Katsuaki Asano, Valerio Vagelli, Anton Dmytriiev, Ryo Yamazaki, M. Vacula, P. Goldoni, Gilles Fontaine, Hiroshi Muraishi, D. Mazin, Samo Stanič, G. Ghirlanda, M. Polo, M. Nievas, M. Lemoine-Goumard, Oleh Petruk, Jose Miguel Miranda, M. Iori, A. Marcowith, Y. Renier, Satoshi Fukami, M. Roncadelli, F. Leone, Takanori Yoshikoshi, Ana Luiza d'Ávila Viana, Y. Fukui, Max Harvey, Sera Markoff, I. Agudo, P. Temnikov, Vincenzo Testa, R. López-Coto, J.D. Mbarubucyeye, Tjark Miener, David Paneque, V. Gammaldi, T. Hassan Collado, H. Abe, L. Bonneau Arbeletche, S. D. Vergani, Sasa Micanovic, P. Vallania, Marina Manganaro, Elena Torresi, M. Giarrusso, G. Ferrand, Paweł Świerk, B. Patricelli, Matteo Cerruti, N. La Palombara, D. Morcuende-Parrilla, V. de Souza, Toshiaki Inada, Yasushi Fukazawa, Werner Hofmann, Michele Doro, E. Pueschel, A. Araudo, E. Sciacca, Thomas Lohse, A. Djannati-Ataï, Abdalla, H., Abe, H., Acero, F., Acharyya, A., Adam, R., Agudo, I., Aguirre-Santaella, A., Alfaro, R., Alfaro, J., Alispach, C., Aloisio, R., Alves Batista, R., Amati, L., Amato, E., Ambrosi, G., Ang??ner, E. O., Araudo, A., Armstrong, T., Arqueros, F., Arrabito, L., Asano, K., Ascas??bar, Y., Ashley, M., Backes, M., Balazs, C., Balbo, M., Balmaverde, B., Baquero Larriva, A., Barbosa Martins, V., Barkov, M., Baroncelli, L., Barres de Almeida, U., Barrio, J. A., Batista, P. -I., Becerra Gonz??lez, J., Becherini, Y., Beck, G., Becker Tjus, J., Belmont, R., Benbow, W., Bernardini, E., Berti, A., Berton, M., Bertucci, B., Beshley, V., Bi, B., Biasuzzi, B., Biland, A., Bissaldi, E., Biteau, J., Blanch, O., Bocchino, F., Boisson, C., Bolmont, J., Bonanno, G., Bonneau Arbeletche, L., Bonnoli, G., Bordas, P., Bottacini, E., B??ttcher, M., Bozhilov, V., Bregeon, J., Brill, A., Brown, A. M., Bruno, P., Bruno, A., Bulgarelli, A., Burton, M., Buscemi, M., Caccianiga, A., Cameron, R., Capasso, M., Caprai, M., Caproni, A., Capuzzo-Dolcetta, R., Caraveo, P., Carosi, R., Carosi, A., Casanova, S., Cascone, E., Cauz, D., Cerny, K., Cerruti, M., Chadwick, P., Chaty, S., Chen, A., Chernyakova, M., Chiaro, G., Chiavassa, A., Chytka, L., Conforti, V., Conte, F., Contreras, J. L., Coronado-Blazquez, J., Cortina, J., Costa, A., Costantini, H., Covino, S., Cristofari, P., Cuevas, O., D'Ammando, F., Daniel, M. K., Davies, J., Dazzi, F., De Angelis, A., de Bony de Lavergne, M., De Caprio, V., de C??ssia dos Anjos, R., de Gouveia Dal Pino, E. M., De Lotto, B., De Martino, D., de Naurois, M., de O??a Wilhelmi, E., De Palma, F., de Souza, V., Delgado, C., Della Ceca, R., della Volpe, D., Depaoli, D., Di Girolamo, T., Di Pierro, F., D??az, C., D??az-Bahamondes, C., Diebold, S., Djannati-Ata??, A., Dmytriiev, A., Dom??nguez, A., Donini, A., Dorner, D., Doro, M., Dournaux, J., Dwarkadas, V. V., Ebr, J., Eckner, C., Einecke, S., Ekoume, T. R. N., Els??sser, D., Emery, G., Evoli, C., Fairbairn, M., Falceta-Goncalves, D., Fegan, S., Feng, Q., Ferrand, G., Fiandrini, E., Fiasson, A., Fioretti, V., Foffano, L., Fonseca, M. V., Font, L., Fontaine, G., Franco, F. J., Freixas Coromina, L., Fukami, S., Fukazawa, Y., Fukui, Y., Gaggero, D., Galanti, G., Gammaldi, V., Garcia, E., Garczarczyk, M., Gascon, D., Gaug, M., Gent, A., Ghalumyan, A., Ghirlanda, G., Gianotti, F., Giarrusso, M., Giavitto, G., Giglietto, N., Giordano, F., Glicenstein, J., Goldoni, P., Gonz??lez, J. M., Gourgouliatos, K., Grabarczyk, T., Grandi, P., Granot, J., Grasso, D., Green, J., Grube, J., Gueta, O., Gunji, S., Halim, A., Harvey, M., Hassan Collado, T., Hayashi, K., Heller, M., Hern??ndez Cadena, S., Hervet, O., Hinton, J., Hiroshima, N., Hnatyk, B., Hnatyk, R., Hoffmann, D., Hofmann, W., Holder, J., Horan, D., H??randel, J., Horvath, P., Hovatta, T., Hrabovsky, M., Hrupec, D., Hughes, G., H??tten, M., Iarlori, M., Inada, T., Inoue, S., Insolia, A., Ionica, M., Iori, M., Jacquemont, M., Jamrozy, M., Janecek, P., Jim??nez Mart??nez, I., Jin, W., Jung-Richardt, I., Jurysek, J., Kaaret, P., Karas, V., Karkar, S., Kawanaka, N., Kerszberg, D., Kh??lifi, B., Kissmann, R., Kn??dlseder, J., Kobayashi, Y., Kohri, K., Komin, N., Kong, A., Kosack, K., Kubo, H., La Palombara, N., Lamanna, G., Lang, R. G., Lapington, J., Laporte, P., Lefaucheur, J., Lemoine-Goumard, M., Lenain, J., Leone, F., Leto, G., Leuschner, F., Lindfors, E., Lloyd, S., Lohse, T., Lombardi, S., Longo, F., Lopez, A., L??pez, M., L??pez-Coto, R., Loporchio, S., Lucarelli, F., Luque-Escamilla, P. L., Lyard, E., Maggio, C., Majczyna, A., Makariev, M., Mallamaci, M., Mandat, D., Maneva, G., Manganaro, M., Manic??, G., Marcowith, A., Marculewicz, M., Markoff, S., Marquez, P., Mart??, J., Martinez, O., Mart??nez, M., Mart??nez, G., Mart??nez-Huerta, H., Maurin, G., Mazin, D., Mbarubucyeye, J. D., Medina Miranda, D., Meyer, M., Micanovic, S., Miener, T., Minev, M., Miranda, J. M., Mitchell, A., Mizuno, T., Mode, B., Moderski, R., Mohrmann, L., Molina, E., Montaruli, T., Moralejo, A., Morales Merino, J., Morcuende-Parrilla, D., Morselli, A., Mukherjee, R., Mundell, C., Murach, T., Muraishi, H., Nagai, A., Nakamori, T., Nemmen, R., Niemiec, J., Nieto, D., Nievas, M., Nikolajuk, M., Nishijima, K., Noda, K., Nosek, D., Nozaki, S., O'Brien, P., Ohira, Y., Ohishi, M., Oka, T., Ong, R. A., Orienti, M., Orito, R., Orlandini, M., Orlando, E., Osborne, J. P., Ostrowski, M., Oya, I., Pagliaro, A., Palatka, M., Paneque, D., Pantaleo, F. R., Paredes, J. M., Parmiggiani, N., Patricelli, B., Pavleti??, L., Pe'Er, A., Pech, M., Pecimotika, M., Peresano, M., Persic, M., Petruk, O., Pfrang, K., Piatteli, P., Pietropaolo, E., Pillera, R., Pilszyk, B., Pimentel, D., Pintore, F., Pita, S., Pohl, M., Poireau, V., Polo, M., Prado, R. R., Prast, J., Principe, G., Produit, N., Prokoph, H., Prouza, M., Przybilski, H., Pueschel, E., P??hlhofer, G., Pumo, M. L., Punch, M., Queiroz, F., Quirrenbach, A., Rando, R., Razzaque, S., Rebert, E., Recchia, S., Reichherzer, P., Reimer, O., Reimer, A., Renier, Y., Reposeur, T., Rhode, W., Ribeiro, D., Rib??, M., Richtler, T., Rico, J., Rieger, F., Rizi, V., Rodriguez, J., Rodriguez Fernandez, G., Rodriguez Ramirez, J. C., Rodr??guez V??zquez, J. J., Romano, P., Romeo, G., Roncadelli, M., Rosado, J., Rosales de Leon, A., Rowell, G., Rudak, B., Rujopakarn, W., Russo, F., Sadeh, I., Saha, L., Saito, T., Salesa Greus, F., Sanchez, D., S??nchez-Conde, M., Sangiorgi, P., Sano, H., Santander, M., Santos, E. M., Sanuy, A., Sarkar, S., Saturni, F. G., Sawangwit, U., Scherer, A., Schleicher, B., Schovanek, P., Schussler, F., Schwanke, U., Sciacca, E., Scuderi, S., Seglar Arroyo, M., Sergijenko, O., Servillat, M., Seweryn, K., Shalchi, A., Sharma, P., Shellard, R. C., Siejkowski, H., Sinha, A., Sliusar, V., Slowikowska, A., Sokolenko, A., Sol, H., Specovius, A., Spencer, S., Spiga, D., Stamerra, A., Stani??, S., Starling, R., Stolarczyk, T., Straumann, U., Stri??kovi??, J., Suda, Y., wierk, P., Tagliaferri, G., Takahashi, H., Takahashi, M., Tavecchio, F., Taylor, L., Tejedor, L. A., Temnikov, P., Terrier, R., Terzic, T., Testa, V., Tian, W., Tibaldo, L., Tonev, D., Torres, D. F., Torresi, E., Tosti, L., Tothill, N., Tovmassian, G., Travnicek, P., Truzzi, S., Tuossenel, F., Umana, G., Vacula, M., Vagelli, V., Valentino, M., Vallage, B., Vallania, P., van Eldik, C., Varner, G. S., Vassiliev, V., V??zquez Acosta, M., Vecchi, M., Veh, J., Vercellone, S., Vergani, S., Verguilov, V., Vettolani, G. P., Viana, A., Vigorito, C. F., Vitale, V., Vorobiov, S., Vovk, I., Vuillaume, T., Wagner, S. J., Walter, R., Watson, J., White, M., White, R., Wiemann, R., Wierzcholska, A., Will, M., Williams, D. A., Wischnewski, R., Wolter, A., Yamazaki, R., Yanagita, S., Yang, L., Yoshikoshi, T., Zacharias, M., Zaharijas, G., Zaric, D., Zavrtanik, M., Zavrtanik, D., Zdziarski, A. A., Zech, A., Zechlin, H., Zhdanov, V. I., ivec, M., Comisión Nacional de Investigación Científica y Tecnológica (Chile), Ministry of Education, Youth and Sports (Czech Republic), Academy of Finland, Istituto Nazionale di Astrofisica, National Science Centre (Poland), Slovenian Research Agency, European Commission, Ministerio de Economía y Competitividad (España), Ministerio de Ciencia e Innovación (España), Junta de Andalucía, Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Laboratoire Leprince-Ringuet (LLR), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Centre de Physique des Particules de Marseille (CPPM), Aix Marseille Université (AMU)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Univers et Particules de Montpellier (LUPM), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Montpellier 2 - Sciences et Techniques (UM2), Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Laboratoire Univers et Théories (LUTH (UMR_8102)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7), Laboratoire de Physique Nucléaire et de Hautes Énergies (LPNHE (UMR_7585)), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Laboratoire d'Annecy de Physique des Particules (LAPP), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), AstroParticule et Cosmologie (APC (UMR_7164)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Centre d'Etudes Nucléaires de Bordeaux Gradignan (CENBG), Université Sciences et Technologies - Bordeaux 1-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), CTA, UAM. Departamento de Física Teórica, Batista, R. A., Anguner, E. O., Ascasibar, Y., Larriva, A. B., Martins, V. B., De Almeida, U. B., Gonzalez, J. B., Tjus, J. B., Arbeletche, L. B., Bottcher, M., Angelis, A. D., De Lavergne, M. D. B., Caprio, V. D., De Dos Anjos, R. C., De Gouveia Dal Pino, E. M., Lotto, B. D., Martino, D. D., De Naurois, M., Wilhelmi, E. D. O., DE PALMA, F., De Souza, V., Ceca, R. D., Volpe, D. D., Girolamo, T. D., Pierro, F. D., Diaz, C., Diaz-Bahamondes, C., Djannati-Atai, A., Dominguez, A., Elsasser, D., Coromina, L. F., Gonzalez, J. M., Collado, T. H., Cadena, S. H., Horandel, J., Hutten, M., Martinez, I. J., Khelifi, B., Knodlseder, J., Palombara, N. L., Lopez, M., Lopez-Coto, R., Manico, G., Marti, J., Martinez, M., Martinez, G., Martinez-Huerta, H., Miranda, D. M., Merino, J. M., Pavletic, L., Puhlhofer, G., Ribo, M., Fernandez, G. R., Ramirez, J. C. R., Vazquez, J. J. R., De Leon, A. R., Greus, F. S., Sanchez-Conde, M., Arroyo, M. S., Stanic, S., Striskovic, J., Swierk, P., Eldik, C. V., Acosta, M. V., Zivec, M., Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Galaxies, Etoiles, Physique, Instrumentation (GEPI), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Abdalla H., Abe H., Acero F., Acharyya A., Adam R., Agudo I., Aguirre-Santaella A., Alfaro R., Alfaro J., Alispach C., Aloisio R., Batista R.A., Amati L., Amato E., Ambrosi G., Anguner E.O., Araudo A., Armstrong T., Arqueros F., Arrabito L., Asano K., Ascasibar Y., Ashley M., Backes M., Balazs C., Balbo M., Balmaverde B., Larriva A.B., Martins V.B., Barkov M., Baroncelli L., De Almeida U.B., Barrio J.A., Batista P.-I., Gonzalez J.B., Becherini Y., Beck G., Tjus J.B., Belmont R., Benbow W., Bernardini E., Berti A., Berton M., Bertucci B., Beshley V., Bi B., Biasuzzi B., Biland A., Bissaldi E., Biteau J., Blanch O., Bocchino F., Boisson C., Bolmont J., Bonanno G., Arbeletche L.B., Bonnoli G., Bordas P., Bottacini E., Bottcher M., Bozhilov V., Bregeon J., Brill A., Brown A.M., Bruno P., Bruno A., Bulgarelli A., Burton M., Buscemi M., Caccianiga A., Cameron R., Capasso M., Caprai M., Caproni A., Capuzzo-Dolcetta R., Caraveo P., Carosi R., Carosi A., Casanova S., Cascone E., Cauz D., Cerny K., Cerruti M., Chadwick P., Chaty S., Chen A., Chernyakova M., Chiaro G., Chiavassa A., Chytka L., Conforti V., Conte F., Contreras J.L., Coronado-Blazquez J., Cortina J., Costa A., Costantini H., Covino S., Cristofari P., Cuevas O., D'Ammando F., Daniel M.K., Davies J., Dazzi F., Angelis A.D., De Lavergne M.D.B., Caprio V.D., De Dos Anjos R.C., De Gouveia Dal Pino E.M., Lotto B.D., Martino D.D., De Naurois M., Wilhelmi E.D.O., Palma F.D., De Souza V., Delgado C., Ceca R.D., Volpe D.D., Depaoli D., Girolamo T.D., Pierro F.D., Diaz C., Diaz-Bahamondes C., Diebold S., Djannati-Atai A., Dmytriiev A., Dominguez A., Donini A., Dorner D., Doro M., Dournaux J., Dwarkadas V.V., Ebr J., Eckner C., Einecke S., Ekoume T.R.N., Elsasser D., Emery G., Evoli C., Fairbairn M., Falceta-Goncalves D., Fegan S., Feng Q., Ferrand G., Fiandrini E., Fiasson A., Fioretti V., Foffano L., Fonseca M.V., Font L., Fontaine G., Franco F.J., Coromina L.F., Fukami S., Fukazawa Y., Fukui Y., Gaggero D., Galanti G., Gammaldi V., Garcia E., Garczarczyk M., Gascon D., Gaug M., Gent A., Ghalumyan A., Ghirlanda G., Gianotti F., Giarrusso M., Giavitto G., Giglietto N., Giordano F., Glicenstein J., Goldoni P., Gonzalez J.M., Gourgouliatos K., Grabarczyk T., Grandi P., Granot J., Grasso D., Green J., Grube J., Gueta O., Gunji S., Halim A., Harvey M., Collado T.H., Hayashi K., Heller M., Cadena S.H., Hervet O., Hinton J., Hiroshima N., Hnatyk B., Hnatyk R., Hoffmann D., Hofmann W., Holder J., Horan D., Horandel J., Horvath P., Hovatta T., Hrabovsky M., Hrupec D., Hughes G., Hutten M., Iarlori M., Inada T., Inoue S., Insolia A., Ionica M., Iori M., Jacquemont M., Jamrozy M., Janecek P., Martinez I.J., Jin W., Jung-Richardt I., Jurysek J., Kaaret P., Karas V., Karkar S., Kawanaka N., Kerszberg D., Khelifi B., Kissmann R., Knodlseder J., Kobayashi Y., Kohri K., Komin N., Kong A., Kosack K., Kubo H., Palombara N.L., Lamanna G., Lang R.G., Lapington J., Laporte P., Lefaucheur J., Lemoine-Goumard M., Lenain J., Leone F., Leto G., Leuschner F., Lindfors E., Lloyd S., Lohse T., Lombardi S., Longo F., Lopez A., Lopez M., Lopez-Coto R., Loporchio S., Lucarelli F., Luque-Escamilla P.L., Lyard E., Maggio C., Majczyna A., Makariev M., Mallamaci M., Mandat D., Maneva G., Manganaro M., Manico G., Marcowith A., Marculewicz M., Markoff S., Marquez P., Marti J., Martinez O., Martinez M., Martinez G., Martinez-Huerta H., Maurin G., Mazin D., Mbarubucyeye J.D., Miranda D.M., Meyer M., Micanovic S., Miener T., Minev M., Miranda J.M., Mitchell A., Mizuno T., Mode B., Moderski R., Mohrmann L., Molina E., Montaruli T., Moralejo A., Merino J.M., Morcuende-Parrilla D., Morselli A., Mukherjee R., Mundell C., Murach T., Muraishi H., Nagai A., Nakamori T., Nemmen R., Niemiec J., Nieto D., Nievas M., Nikolajuk M., Nishijima K., Noda K., Nosek D., Nozaki S., O'Brien P., Ohira Y., Ohishi M., Oka T., Ong R.A., Orienti M., Orito R., Orlandini M., Orlando E., Osborne J.P., Ostrowski M., Oya I., Pagliaro A., Palatka M., Paneque D., Pantaleo F.R., Paredes J.M., Parmiggiani N., Patricelli B., Pavletic L., Pe'Er A., Pech M., Pecimotika M., Peresano M., Persic M., Petruk O., Pfrang K., Piatteli P., Pietropaolo E., Pillera R., Pilszyk B., Pimentel D., Pintore F., Pita S., Pohl M., Poireau V., Polo M., Prado R.R., Prast J., Principe G., Produit N., Prokoph H., Prouza M., Przybilski H., Pueschel E., Puhlhofer G., Pumo M.L., Punch M., Queiroz F., Quirrenbach A., Rando R., Razzaque S., Rebert E., Recchia S., Reichherzer P., Reimer O., Reimer A., Renier Y., Reposeur T., Rhode W., Ribeiro D., Ribo M., Richtler T., Rico J., Rieger F., Rizi V., Rodriguez J., Fernandez G.R., Ramirez J.C.R., Vazquez J.J.R., Romano P., Romeo G., Roncadelli M., Rosado J., De Leon A.R., Rowell G., Rudak B., Rujopakarn W., Russo F., Sadeh I., Saha L., Saito T., Greus F.S., Sanchez D., Sanchez-Conde M., Sangiorgi P., Sano H., Santander M., Santos E.M., Sanuy A., Sarkar S., Saturni F.G., Sawangwit U., Scherer A., Schleicher B., Schovanek P., Schussler F., Schwanke U., Sciacca E., Scuderi S., Arroyo M.S., Sergijenko O., Servillat M., Seweryn K., Shalchi A., Sharma P., Shellard R.C., Siejkowski H., Sinha A., Sliusar V., Slowikowska A., Sokolenko A., Sol H., Specovius A., Spencer S., Spiga D., Stamerra A., Stanic S., Starling R., Stolarczyk T., Straumann U., Striskovic J., Suda Y., Swierk P., Tagliaferri G., Takahashi H., Takahashi M., Tavecchio F., Taylor L., Tejedor L.A., Temnikov P., Terrier R., Terzic T., Testa V., Tian W., Tibaldo L., Tonev D., Torres D.F., Torresi E., Tosti L., Tothill N., Tovmassian G., Travnicek P., Truzzi S., Tuossenel F., Umana G., Vacula M., Vagelli V., Valentino M., Vallage B., Vallania P., Eldik C.V., Varner G.S., Vassiliev V., Acosta M.V., Vecchi M., Veh J., Vercellone S., Vergani S., Verguilov V., Vettolani G.P., Viana A., Vigorito C.F., Vitale V., Vorobiov S., Vovk I., Vuillaume T., Wagner S.J., Walter R., Watson J., White M., White R., Wiemann R., Wierzcholska A., Will M., Williams D.A., Wischnewski R., Wolter A., Yamazaki R., Yanagita S., Yang L., Yoshikoshi T., Zacharias M., Zaharijas G., Zaric D., Zavrtanik M., Zavrtanik D., Zdziarski A.A., Zech A., Zechlin H., Zhdanov V.I., Zivec M., ITA, USA, GBR, FRA, DEU, ESP, AUS, BRA, BGR, CHL, HRV, FIN, JPN, IRL, MEX, NAM, NLD, POL, CZE, SVN, SWE, CHE, UKR, Astronomy, High Energy Astrophys. & Astropart. Phys (API, FNWI), and Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Gamma ray Astronomy, Cherenkov Telescope Array, axions, MATÉRIA ESCURA, redshift: dependence, Astronomy, Gamma ray experiments, gamma ray experiments, Astrophysics, 01 natural sciences, Cosmology, Observatory, cosmological model: parameter space, gamma ray experiment, High Energy Astrophysical Phenomena (astro-ph.HE), astro-ph.HE, Physics, Cherenkov telescopes, IACT technique, Gamma rays, Cosmic rays, new physics, 4. Education, Settore FIS/01 - Fisica Sperimentale, Astrophysics::Instrumentation and Methods for Astrophysics, Gamma-ray astronomy, violation: Lorentz, 3. Good health, observatory, Extragalactic background light, astro-ph.CO, axion-like particles, Física nuclear, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Cosmology and Nongalactic Astrophysics, gamma ray: propagation, Cosmology and Nongalactic Astrophysics (astro-ph.CO), Active galactic nucleus, Axions, Astrophysics::High Energy Astrophysical Phenomena, Dark matter, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, invariance: Lorentz, jet: relativistic, dark matter: halo, 0103 physical sciences, active galactic nuclei, extragalactic magnetic fields, AGN, Blazar, background, 010308 nuclear & particles physics, Física, Astronomy and Astrophysics, sensitivity, axion, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], absorption, statistical, Blazars, Telescopes
Abstract

Full list of authors: Abdalla, H.; Abe, H.; Acero, F.; Acharyya, A.; Adam, R.; Agudo, I; Aguirre-Santaella, A.; Alfaro, R.; Alfaro, J.; Alispach, C.; Aloisio, R.; Batista, R. Alves; Amati, L.; Amato, E.; Ambrosi, G.; Anguner, E. O.; Araudo, A.; Armstrong, T.; Arqueros, F.; Arrabito, L.; Asano, K.; Ascasibar, Y.; Ashley, M.; Backes, M.; Balazs, C.; Balbo, M.; Balmaverde, B.; Baquero Larriva, A.; Martins, V. Barbosa; Barkov, M.; Baroncelli, L.; de Almeida, U. Barres; Barrio, J. A.; Batista, P-, I; Becerra Gonzalez, J.; Becherini, Y.; Beck, G.; Tjus, J. Becker; Belmont, R.; Benbow, W.; Bernardini, E.; Berti, A.; Berton, M.; Bertucci, B.; Beshley, V; Bi, B.; Biasuzzi, B.; Biland, A.; Bissaldi, E.; Biteau, J.; Blanch, O.; Bocchino, F.; Boisson, C.; Bolmont, J.; Bonanno, G.; Arbeletche, L. Bonneau; Bonnoli, G.; Bordas, P.; Bottacini, E.; Bottcher, M.; Bozhilov, V; Bregeon, J.; Brill, A.; Brown, A. M.; Bruno, P.; Bruno, A.; Bulgarelli, A.; Burton, M.; Buscemi, M.; Caccianiga, A.; Cameron, R.; Capasso, M.; Caprai, M.; Caproni, A.; Capuzzo-Dolcetta, R.; Caraveo, P.; Carosi, R.; Carosi, A.; Casanova, S.; Cascone, E.; Cauz, D.; Cerny, K.; Cerruti, M.; Chadwick, P.; Chaty, S.; Chen, A.; Chernyakova, M.; Chiaro, G.; Chiavassa, A.; Chytka, L.; Conforti, V; Conte, F.; Contreras, J. L.; Coronado-Blazquez, J.; Cortina, J.; Costa, A.; Costantini, H.; Covino, S.; Cristofari, P.; Cuevas, O.; D'Ammando, F.; Daniel, M. K.; Davies, J.; Dazzi, F.; De Angelis, A.; de Lavergne, M. de Bony; De Caprio, V; dos Anjos, R. de Cassia; Dal Pino, E. M. de Gouveia; De Lotto, B.; De Martino, D.; de Naurois, M.; Wilhelmi, E. de Ona; De Palma, F.; de Souza, V; Delgado, C.; Della Ceca, R.; della Volpe, D.; Depaoli, D.; Di Girolamo, T.; Di Pierro, F.; Diaz, C.; Diaz-Bahamondes, C.; Diebold, S.; Djannati-Atai, A.; Dmytriiev, A.; Dominguez, A.; Donini, A.; Dorner, D.; Doro, M.; Dournaux, J.; Dwarkadas, V. V.; Ebr, J.; Eckner, C.; Einecke, S.; Ekoume, T. R. N.; Elsaesser, D.; Emery, G.; Evoli, C.; Fairbairn, M.; Falceta-Goncalves, D.; Fegan, S.; Feng, Q.; Ferrand, G.; Fiandrini, E.; Fiasson, A.; Fioretti, V; Foffano, L.; Fonseca, M., V; Font, L.; Fontaine, G.; Franco, F. J.; Freixas Coromina, L.; Fukami, S.; Fukazawa, Y.; Fukui, Y.; Gaggero, D.; Galanti, G.; Gammaldi, V; Garcia, E.; Garczarczyk, M.; Gascon, D.; Gaug, M.; Gent, A.; Ghalumyan, A.; Ghirlanda, G.; Gianotti, F.; Giarrusso, M.; Giavitto, G.; Giglietto, N.; Giordano, F.; Glicenstein, J.; Goldoni, P.; Gonzalez, J. M.; Gourgouliatos, K.; Grabarczyk, T.; Grandi, P.; Granot, J.; Grasso, D.; Green, J.; Grube, J.; Gueta, O.; Gunji, S.; Halim, A.; Harvey, M.; Collado, T. Hassan; Hayashi, K.; Heller, M.; Cadena, S. Hernandez; Hervet, O.; Hinton, J.; Hiroshima, N.; Hnatyk, B.; Hnatyk, R.; Hoffmann, D.; Hofmann, W.; Holder, J.; Horan, D.; Horandel, J.; Horvath, P.; Hovatta, T.; Hrabovsky, M.; Hrupec, D.; Hughes, G.; Hutten, M.; Iarlori, M.; Inada, T.; Inoue, S.; Insolia, A.; Ionica, M.; Iori, M.; Jacquemont, M.; Jamrozy, M.; Janecek, P.; Jimenez Martinez, I; Jin, W.; Jung-Richardt, I; Jurysek, J.; Kaaret, P.; Karas, V; Karkar, S.; Kawanaka, N.; Kerszberg, D.; Khelifi, B.; Kissmann, R.; Knodlseder, J.; Kobayashi, Y.; Kohri, K.; Komin, N.; Kong, A.; Kosack, K.; Kubo, H.; La Palombara, N.; Lamanna, G.; Lang, R. G.; Lapington, J.; Laporte, P.; Lefaucheur, J.; Lemoine-Goumard, M.; Lenain, J.; Leone, F.; Leto, G.; Leuschner, F.; Lindfors, E.; Lloyd, S.; Lohse, T.; Lombardi, S.; Longo, F.; Lopez, A.; Lopez, M.; Lopez-Coto, R.; Loporchio, S.; Lucarelli, F.; Luque-Escamilla, P. L.; Lyard, E.; Maggio, C.; Majczyna, A.; Makariev, M.; Mallamaci, M.; Mandat, D.; Maneva, G.; Manganaro, M.; Manico, G.; Marcowith, A.; Marculewicz, M.; Markoff, S.; Marquez, P.; Marti, J.; Martinez, O.; Martinez, M.; Martinez, G.; Martinez-Huerta, H.; Maurin, G.; Mazin, D.; Mbarubucyeye, J. D.; Miranda, D. Medina; Meyer, M.; Micanovic, S.; Miener, T.; Minev, M.; Miranda, J. M.; Mitchell, A.; Mizuno, T.; Mode, B.; Moderski, R.; Mohrmann, L.; Molina, E.; Montaruli, T.; Moralejo, A.; Morales Merino, J.; Morcuende-Parrilla, D.; Morselli, A.; Mukherjee, R.; Mundell, C.; Murach, T.; Muraishi, H.; Nagai, A.; Nakamori, T.; Nemmen, R.; Niemiec, J.; Nieto, D.; Nievas, M.; Nikolajuk, M.; Nishijima, K.; Noda, K.; Nosek, D.; Nozaki, S.; Ohira, Y.; Ohishi, M.; Oka, T.; Ong, R. A.; Orienti, M.; Orito, R.; Orlandini, M.; Orlando, E.; Osborne, J. P.; Ostrowski, M.; Oya, I; Pagliaro, A.; Palatka, M.; Paneque, D.; Pantaleo, F. R.; Paredes, J. M.; Parmiggiani, N.; Patricelli, B.; Pavletic, L.; Pe'er, A.; Pech, M.; Pecimotika, M.; Peresano, M.; Persic, M.; Petruk, O.; Pfrang, K.; Piatteli, P.; Pietropaolo, E.; Pillera, R.; Pilszyk, B.; Pimentel, D.; Pintore, F.; Pita, S.; Pohl, M.; Poireau, V; Polo, M.; Prado, R. R.; Prast, J.; Principe, G.; Produit, N.; Prokoph, H.; Prouza, M.; Przybilski, H.; Pueschel, E.; Puehlhofer, G.; Pumo, M. L.; Punch, M.; Queiroz, F.; Quirrenbach, A.; Rando, R.; Razzaque, S.; Rebert, E.; Recchia, S.; Reichherzer, P.; Reimer, O.; Reimer, A.; Renier, Y.; Reposeur, T.; Rhode, W.; Ribeiro, D.; Ribo, M.; Richtler, T.; Rico, J.; Rieger, F.; Rizi, V; Rodriguez, J.; Fernandez, G. Rodriguez; Ramirez, J. C. Rodriguez; Rodriguez Vazquez, J. J.; Romano, P.; Romeo, G.; Roncadelli, M.; Rosado, J.; de Leon, A. Rosales; Rowell, G.; Rudak, B.; Rujopakarn, W.; Russo, F.; Sadeh, I; Saha, L.; Saito, T.; Greus, F. Salesa; Sanchez, D.; Sanchez-Conde, M.; Sangiorgi, P.; Sano, H.; Santander, M.; Santos, E. M.; Sanuy, A.; Sarkar, S.; Saturni, F. G.; Sawangwit, U.; Scherer, A.; Schleicher, B.; Schovanek, P.; Schussler, F.; Schwanke, U.; Sciacca, E.; Scuderi, S.; Arroyo, M. Seglar; Sergijenko, O.; Servillat, M.; Seweryn, K.; Shalchi, A.; Sharma, P.; Shellard, R. C.; Siejkowski, H.; Sinha, A.; Sliusar, V; Slowikowska, A.; Sokolenko, A.; Sol, H.; Specovius, A.; Spencer, S.; Spiga, D.; Stamerra, A.; Starling, R.; Stolarczyk, T.; Straumann, U.; Striskovic, J.; Suda, Y.; Tagliaferri, G.; Takahashi, H.; Takahashi, M.; Tavecchio, F.; Taylor, L.; Tejedor, L. A.; Temnikov, P.; Terrier, R.; Terzic, T.; Testa, V; Tian, W.; Tibaldo, L.; Tonev, D.; Torres, D. F.; Torresi, E.; Tosti, L.; Tothill, N.; Tovmassian, G.; Travnicek, P.; Truzzi, S.; Tuossenel, F.; Umana, G.; Vacula, M.; Vagelli, V.; Valentino, M.; Vallage, B.; Vallania, P.; van Eldik, C.; Varner, G. S.; Vassiliev, V.; Vazquez Acosta, M.; Vecchi, M.; Veh, J.; Vercellone, S.; Vergani, S.; Verguilov, V.; Vettolani, G. P.; Viana, A.; Vigorito, C. F.; Vitale, V.; Vorobiov, S.; Vovk, I; Vuillaume, T.; Wagner, S. J.; Walter, R.; Watson, J.; White, M.; White, R.; Wiemann, R.; Wierzcholska, A.; Will, M.; Williams, D. A.; Wischnewski, R.; Wolter, A.; Yamazaki, R.; Yanagita, S.; Yang, L.; Yoshikoshi, T.; Zacharias, M.; Zaharijas, G.; Zaric, D.; Zavrtanik, M.; Zavrtanik, D.; Zdziarski, A. A.; Zech, A.; Zechlin, H.; Zhdanov, V., I; Zivec, M., The Cherenkov Telescope Array (CTA), the new-generation ground-based observatory for γ astronomy, provides unique capabilities to address significant open questions in astrophysics, cosmology, and fundamental physics. We study some of the salient areas of γ cosmology that can be explored as part of the Key Science Projects of CTA, through simulated observations of active galactic nuclei (AGN) and of their relativistic jets. Observations of AGN with CTA will enable a measurement of γ absorption on the extragalactic background light with a statistical uncertainty below 15% up to a redshift z=2 and to constrain or detect γ halos up to intergalactic-magnetic-field strengths of at least 0.3 pG . Extragalactic observations with CTA also show promising potential to probe physics beyond the Standard Model. The best limits on Lorentz invariance violation from γ astronomy will be improved by a factor of at least two to three. CTA will also probe the parameter space in which axion-like particles could constitute a significant fraction, if not all, of dark matter. We conclude on the synergies between CTA and other upcoming facilities that will foster the growth of γ cosmology. © 2021 IOP Publishing Ltd and Sissa Medialab., We gratefully acknowledge financial support from the following agencies and organizations: State Committee of Science of Armenia, Armenia; The Australian Research Council, Astronomy Australia Ltd, The University of Adelaide, Australian National University, Monash University, The University of New South Wales, The University of Sydney, Western Sydney University, Australia; Federal Ministry of Education, Science and Research, and Innsbruck University, Austria; Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ), Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP), Ministry of Science, Technology, Innovations and Communications (MCTIC), Brasil; Ministry of Education and Science, National RI Roadmap Project DO1-153/28.08.2018, Bulgaria; The Natural Sciences and Engineering Research Council of Canada and the Canadian Space Agency, Canada; CONICYT-Chile grants CATA AFB 170002, ANID PIA/APOYO AFB 180002, ACT 1406, FONDECYT-Chile grants, 1161463, 1170171, 1190886, 1171421, 1170345, 1201582, Gemini-ANID 32180007, Chile; Croatian Science Foundation, Rudjer Boskovic Institute, University of Osijek, University of Rijeka, University of Split, Faculty of Electrical Engineering, Mechanical Engineering and Naval Architecture, University of Zagreb, Faculty of Electrical Engineering and Computing, Croa tia; Ministry of Education, Youth and Sports, MEYS M2015046, LM2018105, LTT17006, EU/MEYS CZ.02.1.01/0.0/0.0/16_013/0001403, CZ.02.1.01/0.0/0.0/18_046/0016007 and CZ.02.1.01/0.0/0.0/16_019/0000754, Czech Republic; Academy of Finland (grant nr.317636 and 320045), Finland; Ministry of Higher Education and Research, CNRS-INSU and CNRS-IN2P3, CEA-Irfu, ANR, Regional Council Ile de France, Labex ENIGMASS, OCEVU, OSUG2020 and P2IO, France; Max Planck Society, BMBF, DESY, Helmholtz Association, Germany; Department of Atomic Energy, Department of Science and Technology, India; Istituto Nazionale di Astrofisica (INAF), Istituto Nazionale di Fisica Nucleare (INFN), MIUR, Istituto Nazionale di Astrofisica (INAF-OABRERA) Grant Fondazione Cariplo/Regione Lombardia ID 2014-1980/RST_ERC, Italy; ICRR, University of Tokyo, JSPS, MEXT, Japan; Netherlands Research School for Astronomy (NOVA), Netherlands Organization for Scientific Research (NWO), Netherlands; University of Oslo, Norway; Ministry of Science and Higher Education, DIR/WK/2017/12, the National Centre for Research and Development and the National Science Centre, UMO-2016/22/M/ST9/00583, Poland; Slovenian Research Agency, grants P1-0031, P1-0385, I0-0033, J1-9146, J1-1700, N1-0111, and the Young Researcher program, Slovenia; South African Department of Science and Technology and National Research Foundation through the South African Gamma-Ray Astronomy Programme, South Africa; The Spanish groups acknowledge the Spanish Ministry of Science and Innovation and the Spanish Research State Agency (AEI) through grants AYA2016-79724-C4-1-P, AYA2016-80889-P, AYA2016-76012-C3-1-P, BES-2016-076342, FPA2017-82729-C6-1-R, FPA2017-82729-C6-2-R, FPA2017-82729-C6-3-R, FPA2017-82729-C6-4-R, FPA2017-82729-C6-5-R, FPA2017-82729-C6-6-R, PGC2018-095161-B-I00, PGC2018-095512-B-I00, PID2019-107988GB-C22; the “Centro de Excelencia Severo Ochoa” program through grants no. SEV-2016-0597, SEV-2016-0588, SEV-2017-0709, CEX2019-000920-S; the “Unidad de Excelencia María de Maeztu” program through grant no. MDM-2015-0509; the “Ramón y Cajal” programme through grants RYC-2013-14511, RYC-2017-22665; and the MultiDark Consolider Network FPA2017-90566-REDC. They also acknowledge the Atracción de Talento contract no. 2016-T1/TIC-1542 granted by the Comunidad de Madrid; the “Postdoctoral Junior Leader Fellowship” programme from La Caixa Bank ing Foundation, grants no. LCF/BQ/LI18/11630014 and LCF/BQ/PI18/11630012; the “Programa Operativo” FEDER 2014-2020, Consejería de Economía y Conocimiento de la Junta de Andalucía (Ref. 1257737), PAIDI 2020 (Ref. P18-FR-1580) and Universidad de Jaén; “Programa Operativo de Crecimiento Inteligente” FEDER 2014-2020 (Ref. ESFRI-2017-IAC-12), Ministerio de Ciencia e Innovación, 15% co-financed by Consejería de Economía, Industria, Comercio y Conocimiento del Gobierno de Canarias; the Spanish AEI EQC2018-005094-P FEDER 2014-2020; the European Union’s “Horizon 2020” research and innovation programme under Marie Skłodowska-Curie grant agreement no. 665919; and the ESCAPE project with grant no. GA:824064; Swedish Research Council, Royal Physiographic Society of Lund, Royal Swedish Academy of Sciences, The Swedish National Infrastructure for Computing (SNIC) at Lunarc (Lund), Sweden; State Secretariat for Education, Research and Innovation (SERI) and Swiss National Science Foundation (SNSF), Switzerland; Durham University, Leverhulme Trust, Liverpool University, University of Leicester, University of Oxford, Royal Soci ety, Science and Technology Facilities Council, UK; U.S. National Science Foundation, U.S. Department of Energy, Argonne National Laboratory, Barnard College, University of California, University of Chicago, Columbia University, Georgia Institute of Technology, Institute for Nuclear and Particle Astrophysics (INPAC-MRPI program), Iowa State University, the Smithsonian Institution, Washington University McDonnell Center for the Space Sciences, The University of Wisconsin and the Wisconsin Alumni Research Foundation, USA. The research leading to these results has received funding from the European Union’s Seventh Framework Programme (FP7/2007-2013) under grant agreements No 262053 and No 317446. This project is receiving funding from the European Union’s Horizon 2020 research and innovation programs under agreement No 676134. The research leading to these results has received funding from the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement GammaRayCascades No 843800. The Fermi LAT Collaboration acknowledges generous ongoing support from a number of agencies and institutes that have supported both the development and the operation of the LAT as well as scientific data analysis. These include the National Aeronautics and Space Administration and the Department of Energy in the United States, the Commissariat à l’Energie Atomique and the Centre National de la Recherche Scientifique / Institut National de Physique Nucléaire et de Physique des Particules in France, the Agenzia Spaziale Italiana and the Istituto Nazionale di Fisica Nucleare in Italy, the Ministry of Education, Culture, Sports, Science and Technology (MEXT), High Energy Accelerator Research Organization (KEK) and Japan Aerospace Exploration Agency (JAXA) in Japan, and the K. A. Wallenberg Foundation, the Swedish Research Council and the Swedish National Space Board in Sweden. Additional support for science analysis during the operations phase is gratefully acknowledged from the Istituto Nazionale di Astrofisica in Italy and the Centre National d’Études Spatiales in France. This work performed in part under DOE Contract DE-AC02-76SF00515.

Published
2021

25. The Sub-TeV transient Gamma-Ray sky: challenges and opportunities

Author

Giovanni La Mura, Pedro Assis, Alberto Blanco, Rúben Conceição, Paulo Fonte, Luis LOPES, Mário Pimenta, Bernardo Tomé, Catarina Espírito Santo, Luis Mendes, Miguel Ferreira, Pedro Abreu, Pedro Brogueira, Fernando Barão, Ulisses Barres de Almeida, Ronald Shellard, Ugo GIACCARI, Otto Lippmann, Benedetto D’Ettorre Piazzoli, Michele Doro, Elisa Prandini, Cédric Perennes, Giorgio Matthiae, Marco Tavani, Rinaldo Santonico, Alessandro De Angelis, Rubén López Coto, Andrea Chiavassa, Jakub Vicha, Petr Travnicek, and Giuseppe Di Sciascio

Published
2020

26. Star And Planet’s Characterisation Through High Spectral Resolution

Author

Maria Chiara Maimone, Matteo Brogi, Andrea Chiavassa, and Jérémy Leconte

Subjects
Physics, Planet, Astronomy, Star (graph theory), Spectral resolution
Abstract

The study of exoplanets atmospheres is one of the most intriguing challenges in exoplanet field nowadays and the High Resolution Spectroscopy (HRS) has recently emerged as one of the leading methods for detecting atomic and molecular species in their atmospheres. In terms of numbers, if we define the resolution power R, where λ is the wavelength and Δλ is the spectral resolution: R= λ/Δλ then, “High Resolution Spectroscopy” means R > 50 000. Nevertheless extraordinary results have been achieved (Birkby, 2018), High Resolution Spectroscopy alone is not enough. 1D models of the host star have been coupled to HRS observations, but they do not reproduce the complexity of stellar convection mechanism (Chiavassa & Brogi, 2019). On the contrary, 3D Radiative Hydrodynamical simulations (3D RHS) take it into account intrinsically, allowing us to correctly reproduce asymmetric and blue-shifted spectral lines due to the granulation pattern of the stellar disk, which is a very important source of uncertainties at this resolution level (Chiavassa et al. 2017). However, numerical simulations have been computed independently for star and planet so far, while the acquired spectra are an entanglement of both the signals. In particular, some molecular species (e.g, CO) form in the same region of the spectrum, thus planetary and stellar spectral lines are completely mixed and overlapped. Therefore, a next step forward is needed: computing stellar and planetary models together. With our work, we aim at upgrading the already-in-place 3D radiative transfer code Optim3D (Chiavassa et al. 2009) —largely used for stellar purposes so far — to taking into account also the exoplanetary contribution. We propose to use simultaneously 3D RHS, performed for stars, and the innovative Global Climate Model (GCM), drawn up for exoplanets, in order to generate unprecedented precise synthetic spectra. As a springboard to test the code, we are carrying out the analysis of CO and H2O molecules on the well-know benchmark HD189733. Indeed, to disentangle those star’s and its companion’s signals due to the same molecules is one of the most challenging problems. In the end, we will be able to compute a complete dynamic characterisation: on one side, a precise knowledge of the stellar dynamic (i.e. convection-related surface structures) would allow to extract unequivocally the planetary signal; on the other one, a well-modelled dynamic of the planet (i.e. depth, shape, and position of spectral lines) would provide us with considerable information about the planetary atmospheric circulation.

Published
2020

27. VLTI-PIONIER imaging of the red supergiant V602 Carinae

Author

J. C. Guirado, B. Freytag, Andrea Chiavassa, Xavier Haubois, Susanne Höfner, Fabien Baron, Julien Woillez, J. B. Climent, Markus Wittkowski, J. M. Marcaide, European Southern Observatory (ESO), Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Department of Physics and Astronomy [Uppsala], Uppsala University, Observatoire de Paris - Site de Paris (OP), Centre National de la Recherche Scientifique (CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)

Subjects
Physics, Very Large Telescope, 010308 nuclear & particles physics, Flux, FOS: Physical sciences, Astronomy and Astrophysics, Context (language use), Astrophysics, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 01 natural sciences, law.invention, Telescope, Stars, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, law, Angular diameter, 0103 physical sciences, Red supergiant, 010303 astronomy & astrophysics, Image resolution, Solar and Stellar Astrophysics (astro-ph.SR)
Abstract

Context. Red supergiant stars possess surface features and extended molecular atmospheres. Photospheric convection may be a crucial factor of the levitation of the outer atmospheric layers. However, the mechanism responsible is still poorly understood. Aims. We image the stellar surface of V602 Carinae (V602 Car) to constrain the morphology and contrast of the surface features and of the extended atmospheric layers. Methods. We observed V602 Car with the Very Large Telescope Interferometer (VLTI) PIONIER instrument (1.53-1.78 $\mathrm{\mu}$m) between May and July 2016, and April and July 2019 with different telescope configurations. We compared the image reconstructions with 81 temporal snapshots of 3D radiative-hydrodynamics (RHD) CO$^5$BOLD simulations in terms of contrast and morphology, using the Structural Similarity Index. Results. The interferometric data are compatible with an overall spherical disk of angular diameter 4.4$\pm$0.2 mas, and an extended molecular layer. In 2016, the reconstructed image reveals a bright arc-like feature toward the northern rim of the photospheric surface. In 2019, an arc-like feature is seen at a different orientation and a new peak of emission is detected on the opposite side. The contrasts of the reconstructed surface images are 11%$\pm$2% and 9%$\pm$2% for 2016 and 2019, respectively. The morphology and contrast of the two images are consistent with 3D RHD simulations, within our achieved spatial resolution and dynamic range. The extended molecular layer contributes 10--13% of the total flux with an angular diameter of 6--8 mas. It is present but not clearly visible in the reconstructed images because it is close to the limits of the achieved dynamic range. The presence of the molecular layer is not reproduced by the 3D RHD simulations. Conclusions..., Comment: 16 pages, 13 figures, accepted for publication in Astronomy and Astrophysics

Published
2020

28. ELT-HIRES, the high resolution spectrograph for the ELT: the Phase A study and the path to construction

Author

François Bouchy, Andrzej Niedzielski, Thomas Marquart, Stefano Cristiani, Giuseppina Micela, Matteo Genoni, Livia Origlia, Eric Stempels, Philipp Huke, A. Fragoso, I. de Castro Leão, G. Pietrzynski, Valentina D'Odorico, Erik Zackrisson, C. Hansen, E. Niemczura, Graham J. Murray, D. Sosnowska, Andreas Korn, Edwin A. Bergin, Michella Grey Araújo Monteiro, A. Cabral, A. Humphrey, M. R. Zapatero Osorio, P. Figueira, Stefano Covino, Sheila Vilarindo de Sousa, E. Gallo, John D. Monnier, Matteo Aliverti, Igor Coretti, Jose Luis Rasilla, G. Cupani, Sergio Ribeiro Augusto, David Lunney, José Peñate, Luca Pasquini, Lise Christensen, Klaus G. Strassmeier, Phil Rees, Andrea Chiavassa, Marco Riva, C. Lovis, Alessandro Marconi, B. L. Canto Martins, Étienne Artigau, B. Chazelas, Vardan Adibekyan, Enrico Pinna, Nelson J. Nunes, Christoph Mordasini, F. Sortino, Raffaele Gratton, Enric Palle, Rafael Rebolo, Lison Malo, Holger Drass, Isabelle Boisse, Tzu-Chiang Shen, P. Maslowski, I. Hughes, F. Tenegi, P. Parr-Burman, Hans Kjeldsen, René Doyon, A. Mucciarelli, Pedro J. Amado, J. I. González Hernández, Björn Benneke, Andrea Tozzi, Elena Mason, Johan P. U. Fynbo, Roberto Maiolino, M. Woche, C. Allende Prieto, Nikolai Piskunov, M. Amate, D. Romano, Nicoletta Sanna, J. R. De Medeiros, Tim Morris, P. Di Marcantonio, M. Sarajlic, A. Pollo, Xavier Bonfils, R. Calvo-Ortega, Francesco Pepe, Marco Xompero, Paolo Molaro, Roberto Cirami, Philippe Berio, G. Cresci, N. Bezawada, B. Nisini, L. Vanzi, J. Hlavacek-Larrondo, Ansgar Reiners, Ernesto Oliva, Manuel Abreu, M. A. F. de Souza, Stéphane Udry, Martin G. Haehnelt, Luca Valenziano, Michael Weber, S. Becerril, S. Rousseau, Cristina Martins, C. Broeg, Marco Landoni, S. C. C. Barros, V. Cunha Parro, Jochen Liske, I. Di Varano, Driss Kouach, Giorgio Pariani, ITA, USA, GBR, FRA, DEU, ESP, BRA, CAN, CHL, DNK, POL, SWE, CHE, Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, and COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, COSMIC cancer database, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Phase (waves), Astronomy, 01 natural sciences, Exoplanet, 010309 optics, Stars, 0103 physical sciences, Path (graph theory), Spectral resolution, Extremely large telescope, 010303 astronomy & astrophysics, Spectrograph, ComputingMilieux_MISCELLANEOUS
Abstract

HIRES is the high-resolution spectrograph of the European Extremely Large Telescope at optical and near-infrared wavelengths. It consists of three fibre-fed spectrographs providing a wavelength coverage of 0.4-1.8 µm (goal 0.35-2.4 µm) at a spectral resolution of 100,000. The fibre-feeding allows HIRES to have several, interchangeable observing modes including a SCAO module and a small diffraction-limited IFU in the NIR. Therefore, it will be able to operate both in seeing- and diffraction-limited modes. Its modularity will ensure that HIRES can be placed entirely on the Nasmyth platform, if enough mass and volume is available, or part on the Nasmyth and part in the Coud`e room. ELT-HIRES has a wide range of science cases spanning nearly all areas of research in astrophysics and even fundamental physics. Among the top science cases there are the detection of biosignatures from exoplanet atmospheres, finding the fingerprints of the first generation of stars (PopIII), tests on the stability of Nature’s fundamental couplings, and the direct detection of the cosmic acceleration. The HIRES consortium is composed of more than 30 institutes from 14 countries, forming a team of more than 200 scientists and engineers.

Published
2020

29. Gaia Early Data Release 3: Acceleration of the solar system from Gaia astrometry

Author

Vincenzo Ripepi, P. Gavras, M. Vaillant, Mathias Schultheis, László Molnár, E. Poujoulet, Mark Cropper, C. Babusiaux, D. Molina, J. Fernández-Hernández, G. Jevardat de Fombelle, A. de Torres, Aldo Dell'Oro, J. Castañeda, Z. Kostrzewa-Rutkowska, A. Bombrun, André Moitinho, Marcella Marconi, Rossella Cancelliere, M. Hauser, M. Ajaj, C. M. Raiteri, L. Eyer, Michał Pawlak, H. I. Siddiqui, C. Ducourant, Tatiana Muraveva, Tsevi Mazeh, A. Panahi, Federico Marocco, Stefano Bertone, D. Vicente, Patrick Charlot, A. Guerrier, R. De March, Mario Gai, J. Souchay, H. E. P. Lindstrøm, Nicoletta Sanna, Agnes Fienga, Giovanni Comoretto, Jon Marchant, A. Lorca, E. Utrilla, A. Garcia-Gutierrez, Ilaria Musella, L. Balaguer-Núñez, Leanne P. Guy, N. Leclerc, E. Brugaletta, A. Yoldas, Harry Enke, Rosanna Sordo, Zoltan Balog, H. E. Huckle, L. Palaversa, Monica Rainer, T. A. Lister, F. A. Jansen, Ruth Carballo, Alessandro Spagna, J. M. Carrasco, Mikael Granvik, Derek W. Morris, F. Julbe, A. Hutton, J. Osinde, D. W. Evans, M. van Leeuwen, M. Weiler, F. Thévenin, F. Torra, Iain A. Steele, Lorenzo Rimoldini, Alessandro Sozzetti, Francesca Fragkoudi, K. Janßen, O. L. Creevey, J. González-Núñez, T. Pauwels, R. Buzzi, Miguel García-Torres, S. Liao, G. Tauran, Lennart Lindegren, C. Fouron, Pierre Fernique, Céline Reylé, P. Di Matteo, E. Szegedi-Elek, F. Pailler, Stefan Jordan, Roberto Molinaro, Elisabetta Caffau, Federica Spoto, Felix Franke, D. Barbato, Isabelle Lecoeur-Taïbi, Tristan Cantat-Gaudin, Alejandra Recio-Blanco, E. Livanou, W. Roux, X. Peñalosa Esteller, P. A. Palicio, J. H. J. de Bruijne, Sergi Blanco-Cuaresma, Deborah Busonero, F. Riclet, Conny Aerts, Georges Kordopatis, Guy Rixon, F. Solitro, Davide Massari, Mike Smith, D. Baines, Roberto Morbidelli, Gerry Gilmore, G. Plum, Alexey Mints, O. Marchal, Juan Zorec, Ángel Gómez, C. A. Stephenson, Michael Davidson, C. Fabricius, E. Licata, Sergio Messina, Laszlo Szabados, M. Biermann, A. Garofalo, G. Holland, F. De Angeli, Andreas Korn, E. Anglada Varela, Grigori Fedorets, S. Girona, E. Gerlach, Antonella Vallenari, M. Riello, Łukasz Wyrzykowski, Damien Ségransan, F. Taris, L. Bramante, Alberto Cellino, S. Regibo, Andrej Prsa, M. Sarasso, E. Poggio, W. Löffler, Paolo Giacobbe, Jordi Portell, Elisa Distefano, Eric Slezak, I. Bellas-Velidis, Nicolas Rambaux, E. Balbinot, J.-B. Delisle, Maroussia Roelens, E. Salguero, P. de Teodoro, E. van Dillen, Y. Lebreton, Francois Mignard, Sergei A. Klioner, Ulrich Bastian, N. Samaras, G. Orrù, R. E. de Souza, P. Esquej, Paul J. McMillan, A. C. Lanzafame, Sébastien Lambert, Beatrice Bucciarelli, Jose M Hernandez, M. Bernet, S. Ragaini, Gisella Clementini, A. F. Mulone, Ludovic Delchambre, C. Panem, Eric Gosset, P. David, M. Garcia-Reinaldos, Ana Ulla, F. Crifo, J. Guiraud, Mariateresa Crosta, L. Chaoul, C. Diener, Carlos Dafonte, Karri Muinonen, Alex Lobel, J.-L. Bassilana, Maria Süveges, Isabella Pagano, Dimitri Pourbaix, D. Eappachen, M. Haywood, R. Drimmel, Y. Viala, S. Voutsinas, D. Semeux, William Thuillot, N. A. Walton, Paolo Montegriffo, A. Abreu Aramburu, C. Fabre, H. Zhao, Alessandro Bressan, S. Bouquillon, Sanjeev Khanna, T. Lebzelter, N. Tonello, L. Siltala, M. G. Lattanzi, C. Crowley, P. Yvard, Carme Jordi, Elena Pancino, E. del Pozo, Jan Rybizki, Nami Mowlavi, C. Barache, Morgan Fouesneau, J. De Ridder, Ugo Becciani, Martin Altmann, F. van Leeuwen, P. M. Marrese, M. A. Álvarez, A. Jean-Antoine Piccolo, A. F. Lanza, Alberto Vecchiato, Thomas Wevers, Caroline Soubiran, C. P. Murphy, A. M. Piersimoni, Alessandra Mastrobuono-Battisti, Peter G. Jonker, A. Sagristà Sellés, T. Roegiers, S. Marinoni, Johannes Sahlmann, Rene Andrae, P. Sartoretti, G. Altavilla, Raphael Guerra, F. X. Pineau, M. Segol, T. Prusti, J. J. González-Vidal, J. J. Aguado, N. R. Millar, A. Baudesson-Stella, Andrea Chiavassa, Laurent Chemin, C. Turon, H. Steidelmüller, Douglas J. Marshall, A. G. Butkevich, Alberto Riva, P. de Laverny, Simchon Faigler, Laurent Galluccio, A. Mora, P. Re Fiorentin, C. Ordénovic, J. F. Le Campion, A. Delgado, V. Sanchez Gimenez, M. David, G. Sadowski, R. L. Smart, A. Masip, Laia Casamiquela, R. Messineo, R. Mor, J. Bakker, C. Dolding, J. M. Martín-Fleitas, S. Diakite, Coryn A. L. Bailer-Jones, D. Souami, P. Madrero Pardo, Martin A. Barstow, David Teyssier, Ummi Abbas, Jesus Salgado, Paolo Tanga, A. Burlacu, O. Vanel, Ulrike Heiter, Daniel Hestroffer, Sebastian L. Hidalgo, H. E. Delgado, Alberto Krone-Martins, C. Robin, Kevin Benson, Christos Siopis, S. Managau, P. Burgess, Tomaz Zwitter, M. M. S. Marcos Santos, S. Cowell, J. L. Halbwachs, Xavier Luri, Antti Penttilä, R. Geyer, Minia Manteiga, Yassine Damerdji, Nigel Hambly, S. Bartolomé, J. Álvarez Cid-Fuentes, P. Osborne, J. Juaristi Campillo, Mark Taylor, Richard I. Anderson, Y. Le Fustec, Thierry Morel, T. Cornez, Krzysztof A. Rybicki, L. Pulone, N. Bauchet, Pierre Kervella, C. Zurbach, Alfred Castro-Ginard, Frédéric Arenou, P. Ramos, Robert G. Mann, Annie C. Robin, J. C. Segovia, M. Barros, Hector Canovas, D. L. Harrison, Y. Lasne, L. Noval, David Hobbs, E. F. del Peloso, P. Castro Sampol, Yves Fremat, F. De Luise, Daniel Michalik, P. J. Richards, L. Karbevska, N. Hładczuk, K. Kruszyńska, T. Boch, Sofia Randich, A. G. A. Brown, C. Pagani, L. Martin Polo, M. Ramos-Lerate, Krzysztof Nienartowicz, Eduard Masana, E. Racero, E. Fraile, Marc Audard, N. Robichon, Luciana Bianchi, G. Gracia-Abril, R. Santoveña, R. Haigron, N. Unger, Jérôme Berthier, Despina Hatzidimitriou, R. Gutiérrez-Sánchez, M. Fabrizio, I. Gonzalez-Santamaria, A. Dapergolas, P. Panuzzo, Benoit Carry, Francesca Figueras, R. Blomme, Elmé Breedt, D. Munoz, Diego Bossini, G. Busso, D. Katz, Simon Hodgkin, Ennio Poretti, N. Brouillet, Marco Castellani, Nicholas Rowell, Arnaud Siebert, M. Romero-Gómez, Shay Zucker, W. van Reeven, A. Kochoska, G. Giuffrida, Eva Sciacca, T. Carlucci, L. M. Sarro, M. I. Carnerero, Amina Helmi, D. Garabato, B. Holl, Michele Bellazzini, L. Rohrbasser, Teresa Antoja, J. Torra, Thomas Hilger, Pedro García-Lario, Gérard Jasniewicz, Enrique Solano, S. G. Baker, W. J. Cooper, F. Royer, S. Accart, George M. Seabroke, João Alves, Emese Plachy, C. Nicolas, Silvio Leccia, N. Cheek, Uwe Lammers, Ramachrisna Teixeira, Techniche Universtât Desden, Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Lund Observatory, Lund University [Lund], Zentrum für astronomie, Universität Heidelberg [Heidelberg], Department of nuclear medicine, Haukeland University Hospital, University of Bergen (UiB)-University of Bergen (UiB), Merck Serono S.A [Geneva Research Center], Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Universität Heidelberg [Heidelberg] = Heidelberg University, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), Université Nice Sophia Antipolis (... - 2019) (UNS), Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Planetary-system research, Department of Physics, Particle Physics and Astrophysics, Gaia Collaboration, Unidad de Excelencia Científica María de Maeztu Instituto de Ciencias del Cosmos Universidad de Barcelona, MDM-2014-0369, Centro de Excelencia Científica Severo Ochoa, Instituto de Ciencias del Cosmos de la Universidad de Barcelona, SEV2015-0493, Deliste, J. B. [0000-0001-5844-9888], Sozzeti, A. [0000-0002-7504-365X], Forderung der wissenschaftlichen Forschung (FWF), Belgian federal Science Policy Office (BELSPO), Hertha Firnberg Programme, Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP), Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), Comite Francais d'Evaluation de la Cooperation Universitaire et Scientifique avec le Bresil (COFECUB), National Natural Science Foundation of China (NSFC), China Scholarship Council (CSC), European Commission (EC), European Research Council (ERC), Hungarian National Research, Development, and Innovation Office (NKFIH), Science Foundation Ireland (SFI), Israel Science Foundation (ISF), Agenzia Spaziale Italiana (ASI), Istituto Nazionale di Astrofisica (INAF), Netherlands Research School for Astronomy (NOVA), Fundacao para a Ciencia e a Tecnologia (FCT), Agencia Estatal de Investigación (AEI), European Space Agency (ESA), Centre National D'Etudes Spatiales (CNES), Ministero dell'Istruzione, dell'Università e della Ricerca (MIUR), Narodowe Centrum Nauki (NCN), Slovenian Research Agency, Swedish National Space Agency (SNSA), United Kingdom Science and Technology Facilities Council (STFC), Universitat de Barcelona (UB), Generalitat de Catalunya, Xunta de Galicia, Universidad de Cantabria, ITA, European Commission, Ministerio de Ciencia, Innovación y Universidades (España), Ministerio de Economía y Competitividad (España), Astronomy, and Kapteyn Astronomical Institute

Subjects
Data Analysis, Solar System, Astronomy, kinematics and dynamics, virgo cluster, Astrophysics, 01 natural sciences, bar, Astronomi, astrofysik och kosmologi, large-magellanic-cloud, Methods, Astronomy, Astrophysics and Cosmology, 010303 astronomy & astrophysics, Physics, Astrophysics of Galaxies, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Astrophysics::Instrumentation and Methods for Astrophysics, Astrometry, VIRGO CLUSTER, Kinematics and Dynamics, Amplitude, kinematics, Physical Sciences, MILKY-WAY, astrometry, Galaxy: kinematics and dynamics, PROPER MOTION, Proper motion, perturbation, proper motions, reference systems, methods: data analysis, Astrophysics - Astrophysics of Galaxies, FOS: Physical sciences, Context (language use), proper motion, Astronomy & Astrophysics, MASS, Computer Science::Digital Libraries, Gravitational potential, Acceleration, Settore FIS/05 - Astronomia e Astrofisica, 0103 physical sciences, data analysis [methods], Vector spherical harmonics, KINEMATICS, distance, milky-way, Science & Technology, PERTURBATION, 010308 nuclear & particles physics, Astronomy and Astrophysics, kinematics and dynamics [Galaxy], 115 Astronomy, Space science, Physics::History of Physics, BAR, Galaxy, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Astrophysics of Galaxies (astro-ph.GA), DISTANCE, mass, LARGE-MAGELLANIC-CLOUD
Abstract

Context. Gaia Early Data Release 3 (Gaia EDR3) provides accurate astrometry for about 1.6 million compact (QSO-like) extragalactic sources, 1.2 million of which have the best-quality five-parameter astrometric solutions., Aims. The proper motions of QSO-like sources are used to reveal a systematic pattern due to the acceleration of the solar systembarycentre with respect to the rest frame of the Universe. Apart from being an important scientific result by itself, the acceleration measured in this way is a good quality indicator of the Gaia astrometric solution., Methods. Theeffect of the acceleration was obtained as a part of the general expansion of the vector field of proper motions in vector spherical harmonics (VSH). Various versions of the VSH fit and various subsets of the sources were tried and compared to get the most consistent result and a realistic estimate of its uncertainty. Additional tests with the Gaia astrometric solution were used to get a better idea of the possible systematic errors in the estimate., Results. Our best estimate of the acceleration based on Gaia EDR3 is (2.32 +/- 0.16) x 10(-10) m s(-2) (or 7.33 +/- 0.51 km s(-1) Myr-1) towards alpha = 269.1 degrees +/- 5.4 degrees, delta = -31.6 degrees +/- 4.1 degrees, corresponding to a proper motion amplitude of 5.05 +/- 0.35 mu as yr(-1). This is in good agreement with the acceleration expected from current models of the Galactic gravitational potential. We expect that future Gaia data releases will provide estimates of the acceleration with uncertainties substantially below 0.1 mu as yr(-1).

Published
2020
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30. Optical interferometry and Gaia measurement uncertainties reveal the physics of asymptotic giant branch stars

Author

Nicolas Nardetto, Orlagh Creevey, Cyprien Lanthermann, Narsireddy Anugu, Benjamin R. Setterholm, Gail H. Schaefer, Aaron Labdon, B. Freytag, Mathias Schultheis, Florentin Millour, J.-B. Le Bouquin, T. ten Brummelaar, Tyler Gardner, Roxanne Ligi, Andrea Chiavassa, Jacob Ennis, K. Kravchenko, Claire L. Davies, Frédéric Morand, V. Hocdé, Denis Mourard, John Monnier, Stefan Kraus, European Southern Observatory (ESO), Institut d'Astronomie et d'Astrophysique [Bruxelles] (IAA), Université libre de Bruxelles (ULB), Joseph Louis LAGRANGE (LAGRANGE), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Department of Physics and Astronomy [Uppsala], Uppsala University, Instituto de Astrofisica de Canarias (IAC), Departamento de Astrofísica [La laguna], Universidad de La Laguna [Tenerife - SP] (ULL), INAF - Osservatorio Astronomico di Brera (OAB), Istituto Nazionale di Astrofisica (INAF), Institut de Chimie et des Matériaux Paris-Est (ICMPE), Institut de Chimie du CNRS (INC)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France, Center for High Angular Resolution Astronomy (CHARA), Georgia State University, University System of Georgia (USG)-University System of Georgia (USG), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA), Centre National de la Recherche Scientifique (CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), and COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)

Subjects
CHARA, 010504 meteorology & atmospheric sciences, Aperture synthesis, FOS: Physical sciences, Context (language use), Astrophysics, stars: AGB and post-AGB, Astrophysics::Cosmology and Extragalactic Astrophysics, individual: CL Lac [stars], Astronomy & Astrophysics, 01 natural sciences, Computer Science::Digital Libraries, Astronomi, astrofysik och kosmologi, 0103 physical sciences, stars: atmospheres, Radiative transfer, Asymptotic giant branch, Astrophysics::Solar and Stellar Astrophysics, Astronomy, Astrophysics and Cosmology, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, atmospheres [stars], Science & Technology, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy and Astrophysics, Radius, AGB and post-AGB [stars], Galaxy, Physics::History of Physics, interferometric [techniques], Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, techniques: interferometric, CONVECTION, Physical Sciences, Astrophysics::Earth and Planetary Astrophysics, stars: individual: CL Lac, Parallax, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

Context. Asymptotic giant branch stars are cool luminous evolved stars that are well observable across the Galaxy and populating Gaia data. They have complex stellar surface dynamics Aims. On the AGB star CL Lac, it has been shown that the convection-related variability accounts for a substantial part of the Gaia DR2 parallax error. We observed this star with the MIRC-X beam combiner installed at the CHARA interferometer to detect the presence of stellar surface inhomogeneities. Methods. We performed the reconstruction of aperture synthesis images from the interferometric observations at different wavelengths. Then, we used 3D radiative hydrodynamics simulations of stellar convection with CO5BOLD and the post-processing radiative transfer code Optim3D to compute intensity maps in the spectral channels of MIRC-X observations. Then, we determined the stellar radius and compared the 3D synthetic maps to the reconstructed ones focusing on matching the intensity contrast, the morphology of stellar surface structures, and the photocentre position at two different spectral channels, 1.52 and 1.70 micron, simultaneously. Results. We measured the apparent diameter of CL Lac at two wavelengths and recovered the radius using a Gaia parallax. In addition to this, the reconstructed images are characterised by the presence of a brighter area that largely affects the position of the photocentre. The comparison with 3D simulation shows good agreement with the observations both in terms of contrast and surface structure morphology, meaning that our model is adequate for explaining the observed inhomogenities. Conclusions. This work confirms the presence of convection-related surface structures on an AGB star of Gaia DR2. Our result will help us to take a step forward in exploiting Gaia measurement uncertainties to extract the fundamental properties of AGB stars using appropriate RHD simulations., Comment: Accepted for publication on Astronomy and Astrophysics

Published
2020

31. Pulsating chromosphere of classical Cepheids

Author

Andrea Chiavassa, Ph. Mathias, A. Mérand, Behnam Javanmardi, Eric Lagadec, Nancy Remage Evans, D. Gillet, V. Hocdé, Pierre Kervella, Simon Borgniet, Alexandre Gallenne, N. Nardetto, L. Breuval, Joseph Louis LAGRANGE (LAGRANGE), Centre National de la Recherche Scientifique (CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Observatoire de la Côte d'Azur (OCA), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), European Southern Observatory (ESO), Eurecom [Sophia Antipolis], Ecole Polytechnique Fédérale de Lausanne (EPFL), Laboratoire Hippolyte Fizeau (FIZEAU), Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Shock wave, Physics, stars: chromospheres, 010308 nuclear & particles physics, Infrared, Cepheid variable, chemistry.chemical_element, Astronomy and Astrophysics, Astrophysics, shock waves, Calcium, 01 natural sciences, chemistry, 13. Climate action, Space and Planetary Science, 0103 physical sciences, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, Chromosphere, techniques: spectroscopic, stars: variables: Cepheids
Abstract

Context. It has recently been shown that the infrared (IR) emission of Cepheids, constant over the pulsation cycle, might be due to a pulsating shell of ionized gas with a radius of about 15% of that of the star radius, which could be attributed to the chromospheric activity of Cepheids. Aims. The aim of this paper is to investigate the dynamical structure of the chromosphere of Cepheids along the pulsation cycle and to quantify its size. Methods. We present Hα and calcium near-infrared triplet (Ca IR) profile variations using high-resolution spectroscopy with the UVES spectrograph of a sample of 24 Cepheids with a good period coverage from ≈3 to 60 days. After a qualitative analysis of the spectral line profiles, we quantified the Van Hoof effect (velocity gradient between the Hα and Ca IR) as a function of the period of the Cepheids. We then used the Schwarzschild mechanism (a line doubling due to a shock wave) to quantify the size of the chromosphere. Results. We find a significant Van Hoof effect for Cepheids with a period larger than P = 10 days. In particular, Hα lines are delayed with a velocity gradient up to Δv ≈ 30 km s−1 compared to Ca IR. By studying the shocks, we find that the size of the chromosphere of long-period Cepheids is of at least ≈50% of the stellar radius, which is consistent at first order with the size of the shell made of ionized gas previously found from the analysis of IR excess. Last, for most of the long-period Cepheids in the sample, we report a motionless absorption feature in the Hα line that we attribute to a circumstellar envelope that surrounds the chromosphere. Conclusions. Analyzing the Ca IR lines of Cepheids is of importance to potentially unbias the period–luminosity relation from their IR excess, particularly in the context of forthcoming observations of radial velocity measurements from the Radial Velocity Spectrometer on board Gaia, which could be sensitive to their chromosphere.

Published
2020

32. The GALAH survey: accurate radial velocities and library of observed stellar template spectra

Author

Melissa Ness, Luca Casagrande, Dennis Stello, Martin Asplund, Sarah L. Martell, Robert A. Wittenmyer, Prajwal R. Kafle, Sven Buder, Geraint F. Lewis, Jane Lin, Fred Watson, Ulisse Munari, Klemen Čotar, Jeffrey D. Simpson, Thomas Nordlander, Kenneth C. Freeman, Gayandhi M. De Silva, Ly Duong, Daniel B. Zucker, Gregor Traven, Sanjib Sharma, Borja Anguiano, Yuan-Sen Ting, Michael J. Ireland, Maruša Žerja, Karin Lind, Joss Bland-Hawthorn, Jonathan Horner, Andrea Chiavassa, Valentina D'Orazi, David M. Nataf, Katharine J. Schlesinger, Janez Kos, Tomaž Zwitter, Andrew R. Casey, C. G. Tinney, Remo Collet, Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Australian National University (ANU), Anglo-Australian Observatory (AAO), INAF - Osservatorio Astronomico di Padova (OAPD), Istituto Nazionale di Astrofisica (INAF), Sydney Institute for Astronomy (SIfA), The University of Sydney, Research School of Astronomy and Astrophysics [Canberra] (RSAA), Stellar Astrophysics Centre [Aarhus] (SAC), and Aarhus University [Aarhus]

Subjects
astro-ph.SR, astro-ph.GA, Metallicity, media_common.quotation_subject, Dark matter, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, 01 natural sciences, Spectral line, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), ComputingMilieux_MISCELLANEOUS, Astrophysics::Galaxy Astrophysics, media_common, Physics, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 010308 nuclear & particles physics, Stellar atmosphere, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Galaxy, Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Sky, Astrophysics of Galaxies (astro-ph.GA), Astrophysics::Earth and Planetary Astrophysics, Gravitational redshift
Abstract

GALAH is a large-scale magnitude-limited southern stellar spectroscopic survey. Its second data release (GALAH DR2) provides values of stellar parameters and abundances of 23 elements for 342,682 stars (Buder et al.). Here we add a description of the public release of radial velocities with a typical accuracy of 0.1 km/s for 336,215 of these stars, achievable due to the large wavelength coverage, high resolving power and good signal to noise ratio of the observed spectra, but also because convective motions in stellar atmosphere and gravitational redshift from the star to the observer are taken into account. In the process we derive medians of observed spectra which are nearly noiseless, as they are obtained from between 100 and 1116 observed spectra belonging to the same bin with a width of 50 K in temperature, 0.2 dex in gravity, and 0.1 dex in metallicity. Publicly released 1181 median spectra have a resolving power of 28,000 and trace the well-populated stellar types with metallicities between -0.6 and +0.3. Note that radial velocities from GALAH are an excellent match to the accuracy of velocity components along the sky plane derived by Gaia for the same stars. The level of accuracy achieved here is adequate for studies of dynamics within stellar clusters, associations and streams in the Galaxy. So it may be relevant for studies of the distribution of dark matter., Comment: Accepted to MNRAS, compared to the initial submission it now reports radial velocities for more stars (336,215 instead of 199,628) and all radial velocities have been recalculated

Published
2018

33. Tomography of cool giant and supergiant star atmospheres II. Signature of convection in the atmosphere of the red supergiant star $\mu$ Cep

Author

Bernd Freytag, B. Plez, S. Van Eck, Andrea Chiavassa, K. Kravchenko, Thibault Merle, Alain Jorissen, European Southern Observatory (ESO), Institut d'Astronomie et d'Astrophysique [Bruxelles] (IAA), Université libre de Bruxelles (ULB), Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Department of Physics and Astronomy [Uppsala], Uppsala University, Laboratoire Univers et Particules de Montpellier (LUPM), and Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Convection, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Spectral line, spectroscopic [Techniques], 0103 physical sciences, Radiative transfer, Astrophysics::Solar and Stellar Astrophysics, Red supergiant, atmospheres [Stars], 010303 astronomy & astrophysics, Astrophysique, Astrophysics::Galaxy Astrophysics, Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010308 nuclear & particles physics, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Computer Science::Information Retrieval, Astronomy and Astrophysics, AGB and post-AGB [Stars], Acoustic wave, Astronomie, Effective temperature, Sciences de l'espace, Stars, Hysteresis, Supergiants, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, formation [Line], Astrophysics::Earth and Planetary Astrophysics, Supergiant
Abstract

Context. Red supergiants are cool massive stars and are the largest and the most luminous stars in the Universe. They are characterized by irregular or semi-regular photometric variations, the physics of which is not clearly understood. Aims. The paper aims to derive the velocity field in the red supergiant star μ Cep and to relate it to the photometric variability with the help of the tomographic method. Methods. The tomographic method allows one to recover the line-of-sight velocity distribution over the stellar disk and within different optical-depth slices. This method was applied to a series of high-resolution spectra of μ Cep, and these results are compared to those obtained from 3D radiative-hydrodynamics CO5BOLD simulations of red supergiants. Fluctuations in the velocity field are compared with photometric and spectroscopic variations, the latter were derived from the TiO band strength and serve, at least partly, as a proxy of the variations in effective temperature. Results. The tomographic method reveals a phase shift between the velocity and spectroscopic and photometric variations. This phase shift results in a hysteresis loop in the temperature - velocity plane with a timescale of a few hundred days, which is similar to the photometric one. The similarity between the hysteresis loop timescale measured in μ Cep and the timescale of acoustic waves disturbing the convective pattern suggests that such waves play an important role in triggering the hysteresis loops., SCOPUS: ar.j, info:eu-repo/semantics/published

Published
2019

34. The inner dust shell of Betelgeuse detected by polarimetric aperture-masking interferometry

Author

N. M. Kostogryz, Julien Girard, Xavier Haubois, Barnaby Norris, Guy Perrin, C. Pinte, Sylvestre Lacour, Pierre Kervella, Svetlana V. Berdyugina, Peter G. Tuthill, S. T. Ridgway, Andrea Chiavassa, European Southern Observatory (ESO), Sydney Institute for Astronomy (SIfA), The University of Sydney, Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, and COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
010504 meteorology & atmospheric sciences, Mie scattering, FOS: Physical sciences, Context (language use), Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, 0103 physical sciences, Radiative transfer, Astrophysics::Solar and Stellar Astrophysics, Red supergiant, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Physics, Betelgeuse, Photosphere, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Astronomy and Astrophysics, Radius, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Halo, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

Theory surrounding the origin of the dust-laden winds from evolved stars remains mired in controversy. Characterizing the formation loci and the dust distribution within approximately the first stellar radius above the surface is crucial for understanding the physics that underlie the mass-loss phenomenon. By exploiting interferometric polarimetry, we derive the fundamental parameters that govern the dust structure at the wind base of a red supergiant. We present near-infrared aperture-masking observations of Betelgeuse in polarimetric mode obtained with the NACO/SAMPol instrument. We used both parametric models and radiative transfer simulations to predict polarimetric differential visibility data and compared them to SPHERE/ZIMPOL measurements. Using a thin dust shell model, we report the discovery of a dust halo that is located at only 0.5 R$_{\star}$ above the photosphere (i.e. an inner radius of the dust halo of 1.5 R$_{\star}$). By fitting the data under the assumption of Mie scattering, we estimate the grain size and density for various dust species. By extrapolating to the visible wavelengths using radiative transfer simulations, we compare our model with SPHERE/ZIMPOL data and find that models based on dust mixtures that are dominated by forsterite are most favored. Such a close dusty atmosphere has profound implications for the dust formation mechanisms around red supergiants., Accepted in A&A, 10 pages, 20 figures

Published
2019

35. Muon content in air showers between 10 PeV and 1 EeV determined from measurements with KASCADE-Grande

Author

D. Rivera-Rangel, H. Rebel, Markus Roth, T. Huege, G. C. Trinchero, D. Kang, H.O. Klages, C. Morello, J.R. Hörandel, F. Cossavella, Kai Daumiller, J. C. Arteaga-Velázquez, K. Bekk, R. Glasstetter, Frank G. Schröder, Claus Grupen, T. Pierog, J. Oehlschläger, H.J. Gils, H. J. Mathes, J. Blümer, G. Toma, V. de Souza, H.J. Mayer, Andrea Chiavassa, K. Link, E. Cantoni, A. Haungs, S. Schoo, J. Zabierowski, H. Schieler, M. E. Bertaina, J. Milke, H. Ulrich, J. Wochele, Octavian Sima, W. D. Apel, Alexandru Gherghel-Lascu, D. Heck, K. H. Kampert, P. Łuczak, P. Doll, R. Engel, S. Ostapchenko, F. Di Pierro, D. Fuhrmann, and H. Bozdog

Subjects
Physics, Muon, Physics::Instrumentation and Detectors, Astrophysics::High Energy Astrophysical Phenomena, Hadron, Astrophysics::Instrumentation and Methods for Astrophysics, Cosmic ray, Nuclear physics, Shower, Air shower, KASCADE, Content (measure theory), High Energy Physics::Experiment, Zenith
Abstract

Muons in extensive air showers (EAS) are a sensitive probe for the primary cosmic ray mass and the physics of hadronic interactions at very high energies, hence it is important to precisely measure and carefully analyze this particular shower component. In practice, however, such measurements are difficult to carry out due to the penetrating nature of muons and their low density in the shower. This way just in a few experimental facilities the shower muon component has been measured event-by-event in combination with other EAS observables. One of them was the multicomponent air shower experiment KASCADE-Grande, which was designed to study cosmic rays in the energy interval from $1$ PeV to $1$ EeV and was located at the site of the Karlsruhe Institute of Technology, Germany at $110$ m a.s.l. In this work, we will present an analysis of the KASCADE-Grande data in terms of the muon content ($E_\mu > 230$ MeV) of cosmic-ray induced air showers as a function of the primary energy (E = $10$ PeV $- 1$ EeV) and the zenith angle ($< 35^\circ$). We test also the predictions on the shower muon content of the post-LHC hadronic interaction models EPOS-LHC, QGSJET-II-04, SIBYLL 2.3 and SIBYLL 2.3c by comparing the model expectations with experimental results.

Published
2019

36. Constraining convection across the AGB with high-angular-resolution observations

Author

J. Kluska, Alain Jorissen, S. Shetye, Christos Siopis, Markus Wittkowski, B. Freytag, J.-B. Le Bouquin, Sofia Ramstedt, Jean-Phillipe Berger, J. Hron, Andrea Chiavassa, S. Van Eck, A. Mayer, G. Sadowski, Claudia Paladini, Fabien Baron, K. Kravchenko, and Franz Kerschbaum

Subjects
Convection, mass loss [stars], Granule (solar physics), Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, 0103 physical sciences, Asymptotic giant branch, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Astrophysique, convection, Physics, Photosphere, Very Large Telescope, 010308 nuclear & particles physics, Astrophysics::Instrumentation and Methods for Astrophysics, high angular resolution [techniques], Astronomy and Astrophysics, Effective temperature, Astronomie, Surface gravity, AGB and post-AGB [stars], imaging [stars], interferometric [techniques], Interferometry, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics
Abstract

We present very detailed images of the photosphere of an AGB star obtained with the PIONIER instrument, installed at the Very Large Telescope Interferometer (VLTI). The images show a well defined stellar disc populated by a few convective patterns. Thanks to the high precision of the observations we are able to derive the contrast and granulation horizontal scale of the convective pattern for the first time in a direct way. Such quantities are then compared with scaling relations between granule size, effective temperature, and surface gravity that are predicted by simulations of stellar surface convection., SCOPUS: ar.k, info:eu-repo/semantics/published

Published
2019

37. The High-resolution Transmission Spectrum of HD 189733b Interpreted with Atmospheric Doppler Shifts from Three-dimensional General Circulation Models

Author

Eliza M.-R. Kempton, Matteo Brogi, Emily Rauscher, Andrea Chiavassa, Erin Flowers, Grinnell College, Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, and COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Earth and Planetary Astrophysics (astro-ph.EP), Rotation period, Physics, 010504 meteorology & atmospheric sciences, Mathematical model, FOS: Physical sciences, Velocity dispersion, Astronomy and Astrophysics, Rotation, 01 natural sciences, Spectral line, Computational physics, 13. Climate action, Space and Planetary Science, 0103 physical sciences, Hot Jupiter, Radiative transfer, Astrophysics::Earth and Planetary Astrophysics, Spectral resolution, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Astrophysics - Earth and Planetary Astrophysics
Abstract

The signature of wind patterns caused by the interplay of rotation and energy redistribution in hot Jupiters is detectable at high spectral resolution, yet no direct comparison has been attempted between predictions from general circulation models (GCMs) and observed high-resolution spectra. We present the first of such comparisons on near-infrared transmission spectra of the hot Jupiter HD 189733b. Exploring twelve rotation rates and two chemical regimes, we have created model spectra from 3-D GCMs and cross-correlated them with the observed spectra. Comparing our models against those of HD 189733b, we obtain three key results: (1) we confirm CO and H$_2$O in the planet's atmosphere at a detection significance of 8.2$\sigma$; (2) we recover the signature of $\sim$km/s day-to-night winds at $\sim$mbar pressures; and (3) we constrain the rotation period of the planet to between 1.2 and 4.69 days (synchronous rotation (2.2 days) remains consistent with existing observations). Our results do not suffer from the shortcomings of 1-D models as cross correlation templates - mainly that these models tend to over-constrain the slower rotation rates and show evidence for anomalous blue shifts. Our 3-D models instead match the observed line-of-sight velocity of this planet by self-consistently including the effects of high-altitude day-to-night winds. Overall, we find a high degree of consistency between HD 189733b observations and our GCM-based spectra, implying that the physics and chemistry are adequately described in current 3-D forward models for the purpose of interpreting observations at high spectral resolution., Comment: 20 pages, 13 Figures, submitted to AAS Journals, version accepted by AJ

Published
2019

38. Tomography of cool giant and supergiant star atmospheres

Author

Markus Wittkowski, Sophie Van Eck, Richard I. Anderson, Alain Jorissen, Andrea Chiavassa, B. Freytag, K. Kravchenko, Ulli Käufl, European Southern Observatory [Santiago] (ESO), European Southern Observatory (ESO), Institut d'Astronomie et d'Astrophysique [Bruxelles] (IAA), Université libre de Bruxelles (ULB), Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and Uppsala Universitet [Uppsala]

Subjects
FOS: Physical sciences, Context (language use), Astrophysics, 01 natural sciences, spectroscopic [Techniques], 0103 physical sciences, Radiative transfer, Astrophysics::Solar and Stellar Astrophysics, Asymptotic giant branch, atmospheres [Stars], 010303 astronomy & astrophysics, Astrophysique, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, Physics, 010308 nuclear & particles physics, Stellar atmosphere, Astronomy and Astrophysics, AGB and post-AGB [Stars], Astronomie, Sciences de l'espace, Stars, Wavelength, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, interferometric [Techniques], Astrophysics::Earth and Planetary Astrophysics, Tomography, Supergiant, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

Context. Asymptotic giant branch (AGB) stars are characterized by substantial mass loss, however the mechanism behind it not yet fully understood. The knowledge of the structure and dynamics of AGB-star atmospheres is crucial to better understanding the mass loss. The recently established tomographic method, which relies on the design of spectral masks containing lines that form in given ranges of optical depths in the stellar atmosphere, is an ideal technique for this purpose. Aims. We aim to validate the capability of the tomographic method in probing different geometrical depths in the stellar atmosphere and recovering the relation between optical and geometrical depth scales. Methods. We applied the tomographic method to high-resolution spectro-interferometric VLTI/AMBER observations of the Mira-type AGB star S Ori. The interferometric visibilities were extracted at wavelengths contributing to the tomographic masks and fitted to those computed from a uniform disk model. This allows us to measure the geometrical extent of the atmospheric layer probed by the corresponding mask. We then compared the observed atmospheric extension with others measured from available 1D pulsation CODEX models and 3D radiative-hydrodynamics CO5BOLD simulations. Results. While the average optical depths probed by the tomographic masks in S Ori decrease (with â ¨ log τ0»=-0.45,-1.45, and-2.45 from the innermost to the central and outermost layers), the angular diameters of these layers increase, from 10.59 ± 0.09 mas through 11.84 ± 0.17 mas, up to 14.08 ± 0.15 mas. A similar behavior is observed when the tomographic method is applied to 1D and 3D dynamical models. Conclusions. This study derives, for the first time, a quantitative relation between optical and geometrical depth scales when applied to the Mira star S Ori, or to 1D and 3D dynamical models. In the context of Mira-type stars, knowledge of the link between the optical and geometrical depths opens the way to deriving the shock-wave propagation velocity, which cannot be directly observed in these stars., SCOPUS: ar.j, info:eu-repo/semantics/published

Published
2020

39. Gaia Data Release 2

Author

H. E. Huckle, F. Riclet, R. Buzzi, D. J. Marshall, Deborah Busonero, Michael Davidson, C Boeche, Sergio Messina, F. X. Pineau, G. Jasniewicz, L. Balaguer-Núñez, C. A. L. Bailer-Jones, L. Chaoul, J. L. Halbwachs, D. Teyssier, A. F. Lanza, Alberto Vecchiato, Shay Zucker, Francois Taris, Conny Aerts, L. Pulone, Mario Gai, L. M. Sarro, Frédéric Arenou, Á. L. Juhász, Alessandro Bressan, Joao Alves, Morgan Fouesneau, David Hobbs, Yves Fremat, L. Ruiz-Dern, A. Hutton, Sofia Randich, Gerry Gilmore, D. Garabato, Leanne P. Guy, J. González-Núñez, M. Weiler, H. Steidelmüller, D. de Martino, M. A. Álvarez, Vincenzo Ripepi, G. Gracia-Abril, Uwe Lammers, P. de Laverny, G. Sadowski, Nicolas Mary, Bengt Edvardsson, Laszlo Szabados, Łukasz Wyrzykowski, David Barrado, Alberto Cellino, Damien Ségransan, T Roegiers, Olivier Wertz, A. Recio-Blanco, Sergei A. Klioner, J. Durán, A. Panahi, A. Karampelas, Alex Lobel, J.-L. Bassilana, H. Voss, Sven Zschocke, A. Bombrun, F. De Angeli, Toni Santana-Ros, J. C. Segovia, D. Vicente, S. Blanco-Cuaresma, A. G. Butkevich, M. Riello, Amina Helmi, J. Bakker, J. Souchay, A. Kewley, R Alvarez, Daniel Hestroffer, Sergey E. Koposov, Tsevi Mazeh, Maria Süveges, F. F. Suess, P. Drazinos, B. Holl, H. Ziaeepour, T. Wevems, Eva Sciacca, P. Esquej, A. Gueguen, J. Heu, R. Geyer, J. Fernández-Hernández, E. Licata, Laurent Galluccio, J. Cuypers, Peter G. Jonker, Ummi Abbas, Elena Pancino, Jean Surdej, E. Anglada Varela, Michele Bellazzini, Teresa Antoja, Martin A. Barstow, László Molnár, Isabella Pagano, E. Solano, E. Brugaletta, P. Koubsky, Paolo Tanga, Alberto Krone-Martins, M. Clotet, Nigel Hambly, R. L. Smart, Paolo Giacobbe, Simchon Faigler, G. Giuffrida, Aldo Dell'Oro, Yveline Lebreton, Stefano Bertone, Mario G. Lattanzi, Paul S. Barklem, D. Tapiador, Patrick Charlot, A. H. Andrei, Luciano Nicastro, S. Managau, Lorenzo Rimoldini, Mario Di Martino, Paolo Montegriffo, A. Abreu Aramburu, O. Marchal, Marcella Marconi, K. Janßen, K. Findeisen, Xavier Luri, A. Berihuete, M. Schultheis, P. Di Matteo, R. Mor, C. Barata, A. Mora, W. van Reeven, Mikael Granvik, M. Barros, Carine Babusiaux, A. G. A. Brown, Mark Taylor, Y. Le Fustec, T. Lebzelter, Nami Mowlavi, O. L. Creevey, F. Barblan, Thierry Morel, Timo Prusti, A. Riva, S. Girona, S. Liao, Viktor Votruba, Frédéric Royer, Laurent Chemin, G. Altavilla, A. M. Piersimoni, Davide Massari, Marco Delbo, S. Diakite, V. Valette, N. Bach, H. Lenhardt, André Moitinho, Christophe Barache, S. Galleti, Michał Pawlak, A. Yoldas, Harry Enke, Rosanna Sordo, A. Jean-Antoine-Piccolo, Patrice David, Giacomo Cannizzaro, W. Löffler, J. Torra, Tristan Cantat-Gaudin, Marc Audard, D. Katz, Jose M Hernandez, Gijs Nelemans, S. Ragaini, P. Osborne, D. Terrett, A. J. Falcão, D. L. Harrison, G. Plum, R. G. Mann, Ulrike Heiter, Carla Cacciari, Gal Matijevic, J. M. Petit, A. Titarenko, Despina Hatzidimitriou, Juan Zorec, Angela Bragaglia, Nicholas Rowell, Annie C. Robin, Mario David, Tri L. Astraatmadja, Giovanni Comoretto, F. Julbe, Derek W. Morris, R. Drimmel, F. García-Sedano, A. Dapergolas, L. Noval, Mike Smith, Grigori Fedorets, H. Palacin, L. Bramante, D. Molina, Jesus Salgado, C. Dolding, M. Vaillant, Daniel Michalik, H. I. Siddiqui, Minia Manteiga, P. J. Richards, D. Barbato, A. Fonti, Raphael Guerra, J. J. González-Vidal, E. del Pozo, Mariateresa Crosta, M. Žerjal, F. Torra Clotet, C. Diener, M. Hauser, G. Walmsley, Sonia Nieto, I. Bellas-Velidis, T. Boch, Antonella Vallenari, M. Segol, S. Voutsinas, F. Leroux, A. F. Mulone, Pierre Fernique, Céline Reylé, P. Panuzzo, W. Hofmann, S. Bouquillon, F. Crifo, S. Cowell, Ana Ulla, Benoit Carry, C. Ordenovic, F. Pailler, E. Utrilla, Dimitri Pourbaix, A. Hypki, Stefan Jordan, T. Carlucci, Gráinne Costigan, Alfred Castro-Ginard, C. Fabre, C. Crowley, R. Borrachero, Sébastien Lambert, J. H. J. de Bruijne, D. W. Evans, C. Turon, T. Brüsemeister, F. De Luise, R. Haigron, Carme Jordi, G. Marschalkó, C. von Essen, C. Pagani, Katrien Kolenberg, M. van Leeuwen, N. R. Millar, Gisella Clementini, A. de Torres, Ugo Becciani, S. Marinoni, Geraldine Bourda, A. F. Silva, L. Eyer, Misha Haywood, C. Fabricius, Krzysztof Nienartowicz, Miguel García-Torres, S. Regibo, P. Gavras, Gábor Marton, Elisa Distefano, A. Guerrier, H. E. P. Lindstrøm, N. A. Walton, N. Brouillet, G. Eynard Bontemps, T. A. Lister, F. A. Jansen, Ruth Carballo, Steve Vogt, J. M. Carrasco, G. Mantelet, M. Romero-Gómez, Ramachrisna Teixeira, Kjell Eriksson, A. Kochoska, Johannes Sahlmann, Joakim Klar, R. Gutiérrez-Sánchez, Ilaria Musella, L. Palaversa, Karri Muinonen, J. M. Martín-Fleitas, T. Sagristà Sellés, Marco Castellani, Y. Viala, Laia Casamiquela, R. Messineo, Eduard Masana, R. de Souza, H. Stoev, L. Siltala, B. Frezouls, E. Szegedi-Elek, Tomaz Zwitter, G. Kordopatis, C. Ducourant, Tatiana Muraveva, P. Burgess, J. De Ridder, E. Salguero, A. Burlacu, I-C. Shih, U. Stampa, V. Icardi, Iain A. Steele, Alessandro Sozzetti, M. Kontizas, Roberto Molinaro, F. Solitro, H. E. Delgado, G. Holland, J.-B. Lavigne, Andreas Korn, M. Biermann, E. Fraile, M. Fabrizio, Francesca Figueras, R. Blomme, P. Teyssandier, Elisabetta Caffau, G. Busso, Maroussia Roelens, Maarten A. Breddels, Simon Hodgkin, Luciana Bianchi, Olivier Bienaymé, Silvio Leccia, C. Le Poncin-Lafitte, Morgan Fraser, M. Ramos-Lerate, M. Gomes, N. Cheek, J. Osinde, Jérôme Berthier, Kevin Benson, Christos Siopis, P. Balm, E. Gosset, Yassine Damerdji, Richard I. Anderson, C. Zurbach, Jonas Debosscher, G. Cocozza, William O'Mullane, Andrea Chiavassa, F.E. van Leeuwen, Diego Bossini, Federica Spoto, G. Jevardat de Fombelle, Nicoletta Sanna, J. Guiraud, G. Tauran, K. W. Smith, E. Poujoulet, Mark Cropper, Z. Kostrzewa-Rutkowska, F. Glass, J. Gerssen, Thomas Hilger, C.A. Stephenson, D. Ordóñez-Blanco, Andrej Prsa, M. Sarasso, E. Kontizas, Luciana Federici, Paul J. McMillan, Nicolas Rambaux, Ludovic Delchambre, M. Garcia-Reinaldos, T. Pauwels, M. Farràs Casas, S. Bartholomé Muñoz, E. Livanou, E. Van Hemelryck, Roberto Morbidelli, R. Kohley, A. Garofalo, Jovan Veljanoski, Jon Marchant, Jordi Portell, Ulrich Bastian, M. Lopez, Bernardino Arcay, H. Savietto, Alessandro Spagna, A. C. Lanzafame, Beatrice Bucciarelli, C. Panem, Carlos Dafonte, Y. Lasne, P. Sartoretti, E. Racero, William Thuillot, A. Gavel, J. Castañeda, Gaetano Valentini, A. Rivard, E. Poggio, N. Garralda, R. De March, S. G. Baker, S. Accart, M. Altmann, F. Filippi, George M. Seabroke, F. Thévenin, A. van Elteren, Emese Plachy, Lennart Lindegren, Isabelle Lecoeur-Taïbi, Guy Rixon, S Uzzi, M Vaschetto, Francois Mignard, E. Antiche, P. M. Marrese, N. Leclerc, Caroline Soubiran, Rene Andrae, A. Delgado, and Rossella Cancelliere

Subjects
Physics, 010504 meteorology & atmospheric sciences, Astronomy, Astronomy and Astrophysics, galaxies: dwarf, Astrophysics, Astrometry, globular clusters: general, 01 natural sciences, Settore FIS/05 - Astronomia e Astrofisica, Space and Planetary Science, 0103 physical sciences, Local Group, astrometry, High Energy Physics, Galaxy: kinematics and dynamics, astrometry, globular clusters: general, galaxies: dwarf, Local Group, errata, addenda, Galaxy: kinematics and dynamics, addenda, 010303 astronomy & astrophysics, Data release, Astrophysique, errata, 0105 earth and related environmental sciences
Abstract

0, info:eu-repo/semantics/published

Published
2020

40. Temperature gradient in the solar photosphere. Test of a new spectroscopic method and study of its feasibility for ground-based telescopes

Author

Marcel Carbillet, L. Marquis, Andrea Chiavassa, Gilbert Ricort, M. Faurobert, Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, and COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Point spread function, [PHYS.ASTR.IM]Physics [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], Irradiance, Sun: fundamental parameters, FOS: Physical sciences, Context (language use), Astrophysics, instrumentation: adaptive optics, Solar irradiance, 01 natural sciences, 7. Clean energy, 0103 physical sciences, Radiative transfer, Astrophysics::Solar and Stellar Astrophysics, 010306 general physics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Line (formation), Physics, Photosphere, Sun: photosphere, line: profiles, Astronomy and Astrophysics, Computational physics, Temperature gradient, Astrophysics - Solar and Stellar Astrophysics, techniques: imaging spectroscopy, 13. Climate action, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

Context. The contribution of quiet-Sun regions to the solar irradiance variability is currently unclear. Some solar-cycle variations of the quiet-Sun physical structure, such as the temperature gradient, might affect the irradiance. The synoptic measurement of this quantity along the activity cycle would improve our understanding of long-term irradiance variations. Aims. We intend to test a method previously introduced for measuring the photospheric temperature gradient from high-resolution spectroscopic observation and to study its feasibility with ground-based instruments with and without adaptative optics. Methods. We used synthetic profiles of the FeI 630.15 nm obtained from realistic three-dimensional hydrodynamical simulations of the photospheric granulation and line radiative transfer computations under local thermodynamical equilibrium conditions. Synthetic granulation images at different levels in the line are obtained by convolution with the instrumental point spread function (PSF) under various conditions of atmospheric turbulence, with and without correction by an adaptative optics (AO) system. The PSF are obtained with the PAOLA software, and the AO performances are inspired by the system that will be operating on the Daniel K. Inouye Solar Telescope. Results. We consider two different conditions of atmospheric turbulence, with Fried parameters of 7 cm and 5 cm, respectively. We show that the degraded images lead to both a bias and a loss of precision in the temperature-gradient measurement, and that the correction with the AO system allows us to drastically improve the measurement quality. Conclusions. Long-term synoptic observations of the temperature gradient in the solar photosphere can be undertaken by implement- ing this method on ground-based solar telescopes that are equipped with an AO correction system., 7 pages, 9 Figures. Accepted for publication on Astronomy & Astrophysics

Published
2018

41. The Stagger-grid: Synthetic stellar spectra and broad-band photometry

Author

Zazralt Magic, Remo Collet, Martin Asplund, F. Thévenin, L. Bigot, Andrea Chiavassa, Luca Casagrande, Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, and COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Photometry (astronomy), Space and Planetary Science, Broad band, Astronomy and Astrophysics, Astrophysics, Grid, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astronomical spectroscopy, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2018

42. Planet formation imager: project update

Author

Gerd Weigelt, Ernest A. Michael, Florentin Millour, Andrea Isella, Edward H. Wishnow, Kaitlin M. Kratter, Eric L. N. Jensen, Jean Baptiste Le Bouquin, Stephen T. Ridgway, Jean François Gonzalez, Rafael Millan-Gabet, Farzana Meru, David R. Ciardi, Neal J. Turner, Greg Laughlin, Cristina Ramos Almeida, Almudena Alonso-Herrero, S. F. Hoenig, Ming Zhao, Claudia Paladini, Zhaohuan Zhu, Amy Bonsor, O. Panić, L. H. Quiroga-Nuñez, Stephen R. Kane, Ruobing Dong, Stefano Minardi, Andrea Chiavassa, Stephen A. Rinehart, Amelia Bayo, T. ten Brummelaar, Jean Surdej, Alexander Wallace, Attila Juhasz, John D. Ilee, Benjamin J. S. Pope, Matthias R. Schreiber, Konrad R. W. Tristram, Jean Philippe Berger, Gerard T. van Belle, Willem Jan De Wit, Richard P. Nelson, Johan Olofsson, Joerg Uwe Pott, Michael J. Ireland, John Young, Fabien Baron, Mark Reynolds, Sean N. Raymond, Wilhelm Kley, Alessandro Morbidelli, Sebastian Wolf, Tabetha S. Boyajian, Michelle Creech-Eakman, Peter G. Tuthill, Gaspard Duchene, Chris Packham, S. Zúñiga-Fernández, Rene D. Oudmaijer, Sylvestre Lacour, Quentin Kral, Makoto Kishimoto, Lucas Labadie, G. Vasisht, Catherine Espaillat, Poshak Gandhi, Michael D. Smith, Denis Defrere, Andreas Morlok, Chris Mordasini, D. Mozurkewich, Keivan G. Stassun, John D. Monnier, Alexandre Gallenne, Zsolt Regaly, Stefan Kraus, Christopher A. Haniff, Romain Petrov, Markus Wittkowski, Department of Astronomy [Ann Arbor], University of Michigan [Ann Arbor], University of Michigan System-University of Michigan System, Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Cavendish Laboratory, University of Cambridge [UK] (CAM), Joseph Louis LAGRANGE (LAGRANGE), Université Nice Sophia Antipolis (... - 2019) (UNS), Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), European Southern Observatory (ESO), Universidad de Concepción [Chile], School of Physics and Astronomy [Southampton], University of Southampton, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), University of Cyprus [Nicosia], Michelson Science Center (MSC), California Institute of Technology (CALTECH), Friedrich-Schiller-Universität Jena, Centre de Recherches Pétrographiques et Géochimiques (CRPG), Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Queen Mary University of London (QMUL), Institut für Astronomie, Universität Wien (IFA), Universität Wien, ECLIPSE 2018, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), School of Computer Science and Software Engineering [Australia], The University of Western Australia (UWA), National Optical Astronomy Observatory (NOAO), Institut d'Astrophysique et de Géophysique [Liège], Université de Liège, Max-Planck-Institut für Radioastronomie (MPIFR), Department of Materials Science and Engineering, Institute of Ceramics and Glass-Friedrich Alexander University [Erlangen-Nürnberg], Harbin University of Commerce [Heilongjiang], Center for High Angular Resolution Astronomy (CHARA), Georgia State University, University System of Georgia (USG)-University System of Georgia (USG), Space Sciences, Technologies and Astrophysics Research Institute (STAR), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Friedrich-Schiller-Universität = Friedrich Schiller University Jena [Jena, Germany], Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Institute of Ceramics and Glass-Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), University of Michigan System, Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Universidad de Concepción - University of Concepcion [Chile], Centre de Recherche Astrophysique de Lyon (CRAL), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), University of Cyprus [Nicosia] (UCY), Friedrich-Alexander Universität Erlangen-Nürnberg (FAU)-Institute of Ceramics and Glass, Creech-Eakman, Michelle J., Tuthill, Peter G., and Mérand, Antoine

Subjects
Computer science, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Technology development, Protoplanetary disk, 01 natural sciences, PFI, 010309 optics, Planet, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, CubeSat, 010303 astronomy & astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), Astrophysics::Galaxy Astrophysics, ComputingMilieux_MISCELLANEOUS, Planet formation, Earth and Planetary Astrophysics (astro-ph.EP), Infrared interferometry, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy, Large aperture, Exoplanet, Interferometry, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

The Planet Formation Imager (PFI) is a near- and mid-infrared interferometer project with the driving science goal of imaging directly the key stages of planet formation, including the young proto-planets themselves. Here, we will present an update on the work of the Science Working Group (SWG), including new simulations of dust structures during the assembly phase of planet formation and quantitative detection efficiencies for accreting and non-accreting young exoplanets as a function of mass and age. We use these results to motivate two reference PFI designs consisting of a) twelve 3m telescopes with a maximum baseline of 1.2km focused on young exoplanet imaging and b) twelve 8m telescopes optimized for a wider range of young exoplanets and protoplanetary disk imaging out to the 150K H2O ice line. Armed with 4x8m telescopes, the ESO/VLTI can already detect young exoplanets in principle and projects such as MATISSE, Hi-5 and Heimdallr are important PFI pathfinders to make this possible. We also discuss the state of technology development needed to make PFI more affordable, including progress towards new designs for inexpensive, small field-of-view, large aperture telescopes and prospects for Cubesat-based space interferometry., Comment: Presented at 2018 SPIE Astronomical Telescopes + Instrumentation, Austin, Texas, USA. See www.planetformationimager.org for more information

Published
2018

43. Accurate effective temperatures of the metal-poor benchmark stars HD 140283, HD 122563, and HD 103095 from CHARA interferometry

Author

Gail Schaefer, Andrea Chiavassa, Denis Mourard, Luca Casagrande, Karin Lind, O. L. Creevey, Thomas Nordlander, Martin Asplund, Gerry Gilmore, I. Karovicova, Daniel Huber, Paula Jofre, Timothy R. White, Ulrike Heiter, Michael J. Ireland, Markus Wittkowski, F. Thévenin, Laboratoire Hippolyte Fizeau (FIZEAU), Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Department of Physics and Astronomy [Uppsala], Uppsala University, Max-Planck-Institut für Astrophysik (MPA), Max-Planck-Gesellschaft, Research School of Astronomy and Astrophysics [Canberra] (RSAA), Australian National University (ANU), Sydney Institute for Astronomy (SIfA), The University of Sydney, Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Georgia State University, University System of Georgia (USG), Institute of Astronomy [Cambridge], University of Cambridge [UK] (CAM), European Southern Observatory (ESO), Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Gilmore, Gerard [0000-0003-4632-0213], and Apollo - University of Cambridge Repository

Subjects
individual: HD140283 [stars], stars: individual: HD140283, FOS: Physical sciences, individual: HD122563 [stars], Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, 01 natural sciences, Set (abstract data type), surveys, HIPPARCOS, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, stars: individual: HD122563, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, ComputingMilieux_MISCELLANEOUS, Chara, Physics, biology, 010308 nuclear & particles physics, Astronomy and Astrophysics, biology.organism_classification, interferometric [techniques], 3. Good health, Stars, Interferometry, STELLAR, Astrophysics - Solar and Stellar Astrophysics, techniques: interferometric, 13. Climate action, Space and Planetary Science, stars: individual: HD103095, standards, Benchmark (computing), Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], individual: HD103095 [stars], SYSTEM
Abstract

Large stellar surveys of the Milky Way require validation with reference to a set of "benchmark" stars whose fundamental properties are well-determined. For metal-poor benchmark stars, disagreement between spectroscopic and interferometric effective temperatures has called the reliability of the temperature scale into question. We present new interferometric measurements of three metal-poor benchmark stars, HD 140283, HD 122563, and HD 103095, from which we determine their effective temperatures. The angular sizes of all the stars were determined from observations with the PAVO beam combiner at visible wavelengths at the CHARA array, with additional observations of HD 103095 made with the VEGA instrument, also at the CHARA array. Together with photometrically derived bolometric fluxes, the angular diameters give a direct measurement of the effective temperature. For HD 140283 we find {\theta}_LD = 0.324+/-0.005 mas, Teff = 5787+/-48 K; for HD 122563, {\theta}_LD = 0.926+/-0.011 mas, Teff = 4636+/-37 K; and for HD 103095 {\theta}_LD = 0.595+/-0.007 mas, Teff = 5140+/-49 K. Our temperatures for HD 140283 and HD 103095 are hotter than the previous interferometric measurements by 253 K and 322 K, respectively. We find good agreement between our temperatures and recent spectroscopic and photometric estimates. We conclude some previous interferometric measurements have been affected by systematic uncertainties larger than their quoted errors., Comment: 5 pages, 2 figures

Published
2018

44. Extreme Energy Events Project: construction of the detectors

Author

I. Gnesi, L. Votano, P. La Rocca, D. De Gruttola, Luca Baldini, G. Piragino, Marcello Abbrescia, M. Taiuti, S. Serci, Mario Nicola Mazziottai, M. Rizzi, V. V. Frolov, F. Carnesecchi, M. Panareo, C. Ripoli, S. Pisano, Rosario Nania, P. Galeotti, M. C. Vistoli, C. Avanzini, Giancarlo C. Righini, Corrado Cicalo, W. Park, M. Selvi, S. Squarcia, S. Grazzi, G. Sartorelli, A. Scribano, A. Zichichi, R. Zuyeuski, Giuseppe Mandaglio, Riccardo Paoletti, L. Perasso, G. Batignani, E. Bossini, G. Terreni, C. Gustavino, F. Palmonari, Andrea Chiavassa, Federico Pilo, F. Nozzoli, A. Corvaglia, Despina Hatzifotiadou, S. Miozzi, M. C. S. Williams, E. Coccia, Antonio Trifiro, G. Maron, Francesco Riggi, L. Zheng, M. Garbini, S. De Pasquale, F. Fabbri, M. Battaglieri, G. Gemme, Francesco Noferini, Eugenio Scapparone, M. Trimarchi, R. Baldini Ferroli, F. Coccetti, O. Maragoto Rodriguez, S. Boi, M. Schioppa, M. P. Panetta, Luisa Cifarelli, Carnesecchi, Francesca, Abbrescia, M., Avanzini, C., Baldini, Luca, Baldini Ferroli, R., Batignani, G., Battaglieri, M., Boi, S., Bossini, E., Chiavassa, Andrea, Cicalo, C., Cifarelli, L., Coccetti, F., Coccia, E., Corvaglia, A., De Gruttola, Daniele, De Pasquale, S., Fabbri, Franco L., Frolov, V., Galeotti, P., Garbini, M., Gemme, G., Gnesi, Ivan, Grazzi, Stefano, Gustavino, C., Hatzifotiadou, Despina, La Rocca, P., Mandaglio, Giuseppe, Maragoto Rodriguez, O., Maron, G., Mazziottai, Mario Nicola, Miozzi, S., Nania, R., Noferini, F., Nozzoli, F., Palmonari, Federico, Panareo, M., Panetta, M. P., Paoletti, Riccardo, Park, W., Perasso, L., Pilo, Federico, Piragino, G., Pisano, S., Riggi, F., Righini, G. C., Ripoli, C., Rizzi, M., Sartorelli, G., Scapparone, E., Schioppa, Marco, Scribano, A., Selvi, Marco, Serci, S., Squarcia, S., Taiuti, Mauro, Terreni, G., Trifirò, A., Trimarchi, M., Vistoli, M. C., Votano, L., Williams, M. C. S., Zheng, L., Zichichi, A., Zuyeuski, R., Batignani, Giovanni, Cicalo, Corrado, Panetta, M.P., Riggi, Francesco, Righini, G.C., and Vistoli, M.C.

Subjects
Engineering, Large Hadron Collider, Multidisciplinary, business.industry, Detector, MRPC EEE, law.invention, Outreach, Telescope, MRPC, cosmic rays, extreme energy, Extensive Air Showers, Muon spectrometer, law, Quality monitoring, Detectors and Experimental Techniques, business, Telecommunications, Energy (signal processing), Fermi Gamma-ray Space Telescope
Abstract

The Extreme Energy Events (EEE) experiment is a strategic project of Centro Fermi dedicated to the study of extreme energy cosmic rays with an innovative outreach approach: high school students are directly involved in the experiment and play a primary role. EEE exploits a network of muon tracking telescopes constituted by three large area MRPCs. In this work we describe the detector design and the construction phase which is performed at CERN by high school students and teachers. The experiment is coordinated by Centro Fermi with collaboration from INFN, CERN, Ministero dell'Università e della Ricerca (MIUR).Nowadays 525252 telescope are installed all over Italy (3 105 km23~10^5~km^23 105 km2) and a total of 100 institutes participate monitoring the quality of the data and analysing them. The EEE Project is still expanding to enlarge the network, involving more schools.

Published
2018

45. The STAGGER-grid: A grid of 3D stellar atmosphere models

Author

Zazralt Magic, Martin Asplund, Luca Casagrande, Lionel Bigot, Andrea Chiavassa, Frédéric Thévenin, Remo Collet, Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Research School of Astronomy and Astrophysics [Canberra] (RSAA), Australian National University (ANU), Laboratoire Bourguignon des Matériaux et Procédés (LABOMAP), Arts et Métiers Sciences et Technologies, HESAM Université (HESAM)-HESAM Université (HESAM), Observatoire de la Côte d'Azur (OCA), and Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
010504 meteorology & atmospheric sciences, HYDRODYNAMIC SIMULATIONS, fundamental parameters [stars], FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, CHEMICAL-COMPOSITION, 01 natural sciences, Spectral line, Astronomical spectroscopy, photometric [techniques], Photometry (optics), techniques: photometric, 0103 physical sciences, stars: atmospheres, techniques: radial velocities, Radiative transfer, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, atmospheres [stars], Physics, LINE FORMATION, RADIAL-VELOCITY, ZERO POINTS, Stellar atmosphere, radial velocities [techniques], Astronomy and Astrophysics, Effective temperature, SOLAR GRANULATION, Radial velocity, Stars, PHOTONIC PASSBANDS, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, radiative transfer, hydrodynamics, DIGITAL SKY SURVEY, WAVELENGTH SHIFTS, Astrophysics::Earth and Planetary Astrophysics, stars: fundamental parameters, SURFACE CONVECTION, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

Context. The surface structures and dynamics of cool stars are characterized by the presence of convective motions and turbulent flows which shape the emergent spectrum. Aims. We used realistic three-dimensional radiative hydrodynamical simulations from the Stagger-grid to calculate synthetic spectra with the radiative transfer code Optim3D for stars with different stellar parameters to predict photometric colors and convective velocity shifts. Methods. We calculated spectra from 1000 to 200 000 A with a constant resolving power of 20 000 and from 8470 and 8710 A (Gaia Radial Velocity Spectrometer - RVS - spectral range), with a constant resolving power of 300 000. Results. We used synthetic spectra to compute theoretical colors in the Johnson-Cousins UBV(RI), SDSS, 2MASS, Gaia, SkyMapper, Stromgren systems, and HST-WFC3. We showed that 1D versus 3D differences are limited to a small percent except for the narrow filters that span the optical and UV region of the spectrum. In addition, we derived the effect of the convective velocity fields on selected Fe I lines. We found the overall convective shift for 3D simulations with respect to the reference 1D hydrostatic models, revealing line shifts of between -0.235 and +0.361 km/s. We showed a net correlation of the convective shifts with the effective temperature: lower effective temperatures denote redshifts and higher effective temperatures denote blueshifts. We conclude that the extraction of accurate radial velocities from RVS spectra need an appropriate wavelength correction from convection shifts. Conclusions. The use of realistic 3D hydrodynamical stellar atmosphere simulations has a small but significant impact on the predicted photometry compared with classical 1D hydrostatic models for late-type stars. We make all the spectra publicly available for the community through the POLLUX database., Accepted for publication on Astronomy & Astrophysics. All the 3D spectra presented in this work will be soon publicly available for the community through the POLLUX database (http://www.pollux.graal.univ-montp2.fr)

Published
2018

46. VLTI-GRAVITY measurements of cool evolved stars: I. Variable photosphere and extended atmosphere of the Mira star R Peg

Author

Andrea Chiavassa, W. J. de Wit, Xavier Haubois, Gioia Rau, Susanne Höfner, Frank Eisenhauer, Peter R. Wood, Thibaut Paumard, Michael Scholz, and Markus Wittkowski

Subjects
Physics, Photosphere, Very Large Telescope, 010308 nuclear & particles physics, Continuum (design consultancy), FOS: Physical sciences, Astronomy and Astrophysics, Context (language use), Astrophysics, Radius, 01 natural sciences, Stars, Amplitude, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, 0103 physical sciences, Spectral resolution, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR)
Abstract

Dynamic model atmospheres of Mira stars predict variabilities in the photospheric radius and in atmospheric molecular layers which are not yet strongly constrained by observations. Here we measure the variability of the oxygen-rich Mira star R Peg. We used K band spectro-interferometry with a spectral resolution of about 4000 obtained at four epochs between post-maximum and minimum visual phases employing the newly available GRAVITY beam combiner at the VLTI. Our observations show a continuum radius that is anti-correlated with the visual lightcurve. Uniform disc (UD) angular diameters at a near-continuum wavelength of 2.25 mu are steadily increasing with values of 8.7 mas, 9.4 mas, 9.8 mas, and 9.9 mas at visual phases of 0.15, 0.36, 0,45, 0.53, respectively. UD diameters at a bandpass around 2.05 mu, dominated by water vapour, follow the near-continuum variability at larger UD diameters. UD diameters at the CO 2-0 bandhead, instead, are correlated with the visual lightcurve and anti-correlated with the near-continuum UD diameters. The observed anti-correlation between continuum radius and visual lightcurve is consistent with an earlier study of the oxygen-rich Mira S Lac, and with recent 1D CODEX dynamic model atmosphere predictions. The amplitude of the variation is comparable to the earlier observations of S Lac, and smaller than predicted by CODEX models. The wavelength-dependent visibility variations at our epochs can be reproduced by a set of CODEX models at model phases between 0.3 and 0.6. The anti-correlation of water vapour and CO contributions at our epochs suggests that these molecules undergo different processes along the stellar cycle. The newly available GRAVITY instrument is suited to conducting longer time series observations, which are needed to provide strong constraints on the model-predicted intra- and inter-cycle variability., Comment: 5 pages, plus 5 pages appendix. Accepted for publication as a letter by A&A

Published
2018
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47. Large granulation cells on the surface of the giant star π1 Gruis

Author

A. Mayer, Jean-Phillipe Berger, K. Kravchenko, G. Sadowski, Bernd Freytag, Alain Jorissen, S. Shetye, J. Hron, F. Baron, Claudia Paladini, Andrea Chiavassa, Sofia Ramstedt, J.-B. Le Bouquin, Markus Wittkowski, S. Van Eck, Franz Kerschbaum, Jacques Kluska, Christos Siopis, Neovia, Institut d'Astronomie et d'Astrophysique, Université Libre de Bruxelles [Bruxelles] (ULB), Laboratoire d'Astrophysique de Grenoble (LAOG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Univers et Particules de Montpellier (LUPM), Université de Montpellier (UM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), European Southern Observatory (ESO), Institut für Astrophysik [Wien], Universität Wien, Joseph Louis LAGRANGE (LAGRANGE), Université Nice Sophia Antipolis (... - 2019) (UNS), Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Infineon Technologies AG [Neubiberg, Germany], Department of Biochemical and Chemical Engineering, Technische Universität Dortmund [Dortmund] (TU), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Université libre de Bruxelles (ULB), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), and Infineon Technologies AG [München]

Subjects
Physics, Convection, Multidisciplinary, Granule (solar physics), Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Effective temperature, Giant star, Surface gravity, 01 natural sciences, 010309 optics, Stars, 13. Climate action, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Supergiant, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, ComputingMilieux_MISCELLANEOUS, Convection cell
Abstract

Interferometric images of the surface of the giant star π1 Gruis reveal few but large convective cells, consistent with existing models of stellar surface convection. Almost all of what we know about convection on stars is based on observations of the Sun and theoretical calculations. There are around two million convective cells on the surface of the Sun, which are typically around 2,000 kilometres across—less than 0.15 per cent the diameter of the Sun. Theory predicts that, because of the lower surface gravity, giant stars will have much larger cells. Claudia Paladini and collaborators report interferometric imaging of the surface of the giant star π1 Gruis, facilitated by its almost dust-free atmosphere. They find a characteristic convection cell size of about 27 per cent the diameter of the star. This is in line with theoretical predictions. Convection plays a major part in many astrophysical processes, including energy transport, pulsation, dynamos and winds on evolved stars, in dust clouds and on brown dwarfs1,2. Most of our knowledge about stellar convection has come from studying the Sun: about two million convective cells with typical sizes of around 2,000 kilometres across are present on the surface of the Sun3—a phenomenon known as granulation. But on the surfaces of giant and supergiant stars there should be only a few large (several tens of thousands of times larger than those on the Sun) convective cells3, owing to low surface gravity. Deriving the characteristic properties of convection (such as granule size and contrast) for the most evolved giant and supergiant stars is challenging because their photospheres are obscured by dust, which partially masks the convective patterns4. These properties can be inferred from geometric model fitting5,6,7, but this indirect method does not provide information about the physical origin of the convective cells5,6,7. Here we report interferometric images of the surface of the evolved giant star π1 Gruis, of spectral type8,9 S5,7. Our images show a nearly circular, dust-free atmosphere, which is very compact and only weakly affected by molecular opacity. We find that the stellar surface has a complex convective pattern with an average intensity contrast of 12 per cent, which increases towards shorter wavelengths. We derive a characteristic horizontal granule size of about 1.2 × 1011 metres, which corresponds to 27 per cent of the diameter of the star. Our measurements fall along the scaling relations between granule size, effective temperature and surface gravity that are predicted by simulations of stellar surface convection10,11,12.

Published
2018

48. The convective photosphere of the red supergiant CE Tau. I. VLTI/PIONIER H-band interferometric imaging

Author

M. Montargès, B. Tessore, Agnès Lèbre, Ryan Norris, Andrea Chiavassa, and F. Baron

Subjects
CLOSE CIRCUMSTELLAR ENVIRONMENT, STELLAR INTERFEROMETRY, FOS: Physical sciences, Context (language use), Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astronomy & Astrophysics, 7. Clean energy, 01 natural sciences, 010309 optics, Angular diameter, individual: CE Tau [stars], 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Red supergiant, 010303 astronomy & astrophysics, TEMPERATURE, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, Physics, Photosphere, Science & Technology, ANTARES, stars [infrared], Astronomy and Astrophysics, supergiants, mass-loss [stars], Radius, Effective temperature, ATMOSPHERE, imaging [stars], SIMULATIONS, interferometric [techniques], MODEL, Stars, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, GIANTS, Physical Sciences, Astrophysics::Earth and Planetary Astrophysics, Supergiant, BETELGEUSE, STARS
Abstract

Context. Red supergiant stars are one of the latest stages in the evolution of massive stars. Their photospheric convection may play an important role in the launching mechanism of their mass loss; however, its characteristics and dynamics are still poorly constrained. Aims. By observing red supergiant stars with near infrared interferometry at different epochs, we expect to reveal the evolution of bright convective features on their stellar surface. Methods. We observed the M2Iab-Ib red supergiant star CE Tau with the VLTI/PIONIER instrument in the H band at two different epochs separated by one month. Results. We derive the angular diameter of the star and basic stellar parameters, and reconstruct two reliable images of its H-band photosphere. The contrast of the convective pattern of the reconstructed images is $5 \pm 1 \%$ and $6 \pm 1 \%$ for our two epochs of observation. Conclusions. The stellar photosphere shows few changes between the two epochs. The contrast of the convective pattern is below the average contrast variations obtained on 30 randomly chosen snapshots of the best matching 3D radiative hydrodynamics simulation: $23 \pm 1~\%$ for the original simulation images and $16 \pm 1~\%$ for the maps degraded to the reconstruction resolution. We offer two hypotheses to explain this observation. CE Tau may be experiencing a quiet convective activity episode or it could be a consequence of its warmer effective temperature (hence its smaller radius) compared to the simulation., 12 pages, 8 figures. Accepted for publication in Astronomy & Astrophysics

Published
2018

49. Evolution of the magnetic field of Betelgeuse from 2009–2017

Author

Michel Aurière, Guy Perrin, Jason Grunhut, Gregg A. Wade, Jean-François Donati, A. López Ariste, Agnès Lèbre, Miguel Montargès, Andrea Chiavassa, Eric Josselin, Julien Morin, Pierre Kervella, Pascal Petit, R. Konstantinova-Antova, P. Mathias, B. Tessore, Fabrice Herpin, Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Laboratoire Univers et Particules de Montpellier (LUPM), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), FORMATION STELLAIRE 2018, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Joseph Louis LAGRANGE (LAGRANGE), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Софийски университет = Sofia University, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Université de Montpellier (UM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université Nice Sophia Antipolis (... - 2019) (UNS), Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), University of Sofia, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, and COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
NARVAL, ESPADONS, FOS: Physical sciences, Astrophysics, Astronomy & Astrophysics, I, DIAGNOSIS, 01 natural sciences, Computer Science::Digital Libraries, LONG SECONDARY PERIODS, symbols.namesake, 0103 physical sciences, Stokes parameters, Astrophysics::Solar and Stellar Astrophysics, ACTIVE STARS, MASSIVE RED SUPERGIANTS, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Circular polarization, stars: individual: Betelgeuse, Physics, Betelgeuse, Zeeman effect, Science & Technology, individual: Betelgeuse [stars], 010308 nuclear & particles physics, Linear polarization, Computer Science::Information Retrieval, stars: late-type, Astrophysics::Instrumentation and Methods for Astrophysics, stars: magnetic field, Astronomy and Astrophysics, supergiants, Polarization (waves), [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Physics::History of Physics, Magnetic field, Amplitude, [PHYS.ASTR.GA]Physics [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA], Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, magnetic field [stars], CONVECTION, Physical Sciences, symbols, late-type [stars], SPECTROPOLARIMETRY, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], AP
Abstract

Context. Betelgeuse is an M-type supergiant that presents a circularly polarized (Stokes V) signal in its line profiles, interpreted in terms of a surface magnetic field. Aims. The weak circular polarization signal has been monitored over 7.5 years in order to follow its evolution on different timescales, and eventually to determine its physical origin. Linear polarization measurements have also been obtained regularly in the last few years. Methods. We used both the ESPaDOnS and Narval spectropolarimeters to obtain high signal-to-noise ratio spectra, which were processed by means of the least-squares deconvolution method. In order to ensure the reality of the very weak circular polarization, special care has been taken to limit instrumental effects. In addition, several tests were performed on the Stokes V signal to establish its stellar and Zeeman origin. Results. We confirm the magnetic nature of the circular polarization, pointing to a surface magnetic field of the order of 1 G. The Stokes V profiles present variations over different timescales, the most prominent one being close to the long secondary period (LSP; around 2000 d for Betelgeuse) often invoked in red evolved stars. This long period is also dominant for all the other Stokes parameters. The circular polarization is tentatively modeled by means of magnetic field concentrations mimicking spots, showing in particular that the velocity associated with each “spot” also follows the long timescale, and that this signal is nearly always slightly redshifted. Conclusions. From the coupled variations of both linear and circular polarization signatures in amplitude, velocity and timescale, we favour giant convection cells as the main engine at the origin of polarization signatures and variations in all the Stokes parameters. This strengthens support for the hypothesis that large convective cells are at the origin of the LSP.

Published
2018

50. CRIRES high-resolution infrared spectroscopy of the long-period Cepheid l Carinae

Author

B. Trahin, Simon Borgniet, Nicolas Nardetto, P. Mathias, Monica Rainer, V. Hocdé, Denis Mourard, Hilding R. Neilson, Alexandre Gallenne, Antoine Mérand, Andrea Chiavassa, Jesper Storm, Grzegorz Pietrzyński, Wolfgang Gieren, Dariusz Graczyk, Ennio Poretti, Richard I. Anderson, Pierre Kervella, B. Pilecki, Pascal Fouqué, ITA, USA, FRA, CHL, POL, Joseph Louis LAGRANGE (LAGRANGE), Université Nice Sophia Antipolis (... - 2019) (UNS), Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Osservatorio Astronomico di Brera, Istituto Nazionale di Astrofisica (INAF), Laboratoire d'Astrophysique de l'Observatoire Midi-Pyrénées (LATT), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Géoazur (GEOAZUR 7329), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Centre National de la Recherche Scientifique (CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA), European Southern Observatory (ESO), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astronomico di Brera (OAB), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
QUASI-PERIODIC PULSATIONS, Infrared, Cepheid variable, Astrophysics, 01 natural sciences, Spectral line, X-RAY-EMISSION, profiles [line], 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, Line (formation), [PHYS]Physics [physics], Physics, oscillations [Sun], Astrophysics::Instrumentation and Methods for Astrophysics, Radial velocity, Amplitude, Astrophysics - Solar and Stellar Astrophysics, Physical Sciences, spectroscopic [techniques], Astrophysics::Earth and Planetary Astrophysics, stars: oscillations, REGION-IMAGING-SPECTROGRAPH, CORONAL LOOPS, FOS: Physical sciences, Context (language use), Astronomy & Astrophysics, Computer Science::Digital Libraries, ACTIVE-REGION, MAGNETIC-FIELDS, 010309 optics, SOLAR-FLARE, 0103 physical sciences, TRANSITION-REGION, Solar and Stellar Astrophysics (astro-ph.SR), UV radiation [Sun], Science & Technology, line: profiles, Astronomy and Astrophysics, J band, Physics::History of Physics, DOPPLER-SHIFT OSCILLATIONS, flares [Sun], 13. Climate action, Space and Planetary Science, TRANSVERSE OSCILLATIONS, line: formation, X-rays, gamma rays [Sun], [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], techniques: spectroscopic, stars: variables: Cepheids
Abstract

The dynamical structure of the atmosphere of Cepheids has been well studied in the optical. Several authors have found very interesting spectral features in the J band, but little data have been secured beyond 1.6 um. However, such observations can probe different radial velocities and line asymmetry regimes, and are able to provide crucial insights into stellar physics. Our goal was to investigate the infrared line-forming region in the K-band domain, and its impact on the projection factor and the k-term of Cepheids. We secured CRIRES observations for the long-period Cepheid l Car, with a focus on the unblended spectral line NaI2208.969 nm. We measured the corresponding radial velocities (by using the first moment method) and the line asymmetries (by using the bi-Gaussian method). These quantities are compared to the HARPS visible spectra we previously obtained on l Car. The optical and infrared radial velocity curves show the same amplitude (only about 3% of difference), with a slight radial velocity shift of about 0.5 +/- 0.3 km s^-1 between the two curves. Around the minimum radius (phase ~ 0.9) the visible radial velocity curve is found in advance compared to the infrared one (phase lag), which is consistent with an infrared line forming higher in the atmosphere (compared to the visible line) and with a compression wave moving from the bottom to the top of the atmosphere during maximum outward velocity. The asymmetry of the K-band line is also found to be significantly different from that of the optical line., Comment: A&A, in press

Published
2018

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