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1. Study of the bipolar jet of the YSO Th 28 with VLT/SINFONI: Jet morphology and H$_2$ emission

Author

S. Melnikov, P. A. Boley, N. S. Nikonova, A. Caratti o Garatti, R. Garcia Lopez, B. Stecklum, J. Eislöffel, and G. Weigelt

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

$Context.$ The YSO Th 28 possesses a highly collimated jet, which clearly exhibits an asymmetric brightness of its jet lobes at optical and NIR wavelengths. There may be asymmetry in the jet plasma parameters in opposite jet lobes (e.g. electron density, temperature, and outflow velocity). $Aims.$ We examined the Th 28 jet in a 3"x3" where the jet material is collimated and accelerated. Our goal is to map the morphology and determine its physical parameters to determine the physical origin of such asymmetries. $Methods.$ We present $JHK$-spectra of Th 28 obtained with the SINFONI on the (VLT, ESO) in June-July 2015. $Results.$ The [Fe II] emission originates in collimated jet lobes. Two new axial knots are detected at 1" in the blue lobe and 1".2 in the red lobe. The H$_2$ radiation is emitted from an extended region with a radius of $\gtrsim270$ au, which is perpendicular to the jet. The PV diagrams of the bright H$_2$ lines reveal faint H$_2$ emission along both jet lobes as well. The compact and faint H I emission (Pa$\beta$ and Br$\gamma$) comes from two regions, namely from a spherical region around the star and from the jet lobes. The size of the jet launching region is derived as 0".015 ($\sim$3 au at 185 pc), and the initial opening angle of the Th 28 jet is $\sim28^0$, which makes this jet substantially less collimated than most jets from other CTTs. $Conclusions.$ The emission in [Fe II], H$_2$, and H I lines suggests a morphology in which the ionised gas in the disc appears to be disrupted by the jet. The resolved disc-like H$_2$ emission most likely arises in the disc atmosphere from shocks caused by a radial uncollimated wind. The asymmetry of the [Fe II] photocentre shifts with respect to the jet source arises in the immediate vicinity of the driving source of Th28 and suggests that the observed brightness asymmetry is intrinsic as well., Comment: 18 pages, 14 figures

Published
2023

2. PENELLOPE

Author

R. A. B. Claes, C. F. Manara, R. Garcia-Lopez, A. Natta, M. Fang, Z. P. Fockter, P. Ábrahám, J. M. Alcalá, J. Campbell-White, A. Caratti o Garatti, E. Covino, D. Fedele, A. Frasca, J. F. Gameiro, G. J. Herczeg, Á. Kóspál, M. G. Petr-Gotzens, G. Rosotti, L. Venuti, and G. Zsidi

Subjects
stars: variables: T Tauri, accretion, accretion disks, stars: pre-main sequence, stars: variables: T Tauri, Herbig Ae/Be, stars: individual: XX Cha, accretion, Settore FIS/05 - Astronomia e Astrofisica, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, accretion disks, Herbig Ae/Be, FOS: Physical sciences, Astronomy and Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR)
Abstract

The processes regulating protoplanetary disk evolution are constrained by studying how mass accretion rates scale with stellar and disk properties. The spread in these relations can be used as a constraint to the models of disk evolution, but only if the impact of accretion variability is correctly accounted for. While the effect of variability might be substantial in the embedded phases of star formation, it is often considered limited at later stages. Here we report on the observed large variation in the accretion rate for one target, XX Cha, and we discuss the impact on population studies of classical T Tauri stars. The mass accretion rate determined by fitting the UV-to-near-infrared spectrum in recent X-Shooter observations is compared with the one measured with the same instrument 11 years before. XX Cha displays an accretion variability of almost 2 dex between 2010 and 2021. Although the timescales on which this variability happens are uncertain, XX Cha displays an extreme accretion variability for a classical T Tauri star. If such behavior is common among classical T Tauri stars, possibly on longer timescales than previously probed, it could be relevant for discussing the disk evolution models constrained by the observed spread in accretion rates. Finally, we remark that previous studies of accretion variability based on spectral lines may have underestimated the variability of some targets., Accepted for publication in A&A letters

Published
2022
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3. PENELLOPE: The ESO data legacy program to complement the Hubble UV Legacy Library of Young Stars (ULLYSES). I: Survey presentation and accretion properties of Orion OB1 and σ-Orionis

Author

J. Eislöffel, J. Campbell-White, Lynne A. Hillenbrand, I. Mendigutía, J. Alonso-Santiago, Davide Fedele, P. McGinnis, Ágnes Kóspál, Antonio Frasca, T. Thanathibodee, P. C. Schneider, Ł. Tychoniec, Sylvie Cabrit, M. Siwak, M. Koutoulaki, E. Sanchis, F. M. Walter, Giacomo Beccari, Andrea Banzatti, A. Sicilia-Aguilar, M. Gangi, Giovanni P. Rosotti, Myriam Benisty, H. M. J. Boffin, G. A. J. Hussain, C. Ginski, N. Arulanantham, S. Antoniucci, G. J. Herczeg, Jonathan Williams, C. Briceno, K. Maucó, Hans Moritz Günther, J. M. Alcalá, L. Venuti, M. M. James, Anna Miotello, R. Garcia Lopez, G. Zsidi, William J. Fischer, Nuria Calvet, Beate Stelzer, Péter Ábrahám, Elisabetta Rigliaco, Giuseppe Lodato, B. Ercolano, R. Mentel, Francesca Bacciotti, Elvira Covino, Teresa Giannini, J. Erkal, Rene D. Oudmaijer, Leonardo Testi, S. Facchini, Min Fang, A. Caratti o Garatti, Katia Biazzo, Lee Hartmann, E. Fiorellino, Jacco Vink, J. F. Gameiro, Jesús Hernández, K. Grankin, Carlo F. Manara, Massimo Robberto, Lorenzo Spina, Catherine Dougados, Catherine Espaillat, Deirdre Coffey, Jerome Bouvier, Brunella Nisini, High Energy Astrophys. & Astropart. Phys (API, FNWI), and Low Energy Astrophysics (API, FNWI)

Subjects
Protoplanetary disks, Accretion, 010504 meteorology & atmospheric sciences, Continuum (design consultancy), Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Spectral line, Planet, 0103 physical sciences, Cluster (physics), Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Stars: variables: T Tauri, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Complement (set theory), Line (formation), Physics, Herbig Ae/Be, Astronomy and Astrophysics, Accretion (astrophysics), Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Accretion disks, Stars: pre-main sequence, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

The evolution of young stars and disks is driven by the interplay of several processes, notably accretion and ejection of material. Critical to correctly describe the conditions of planet formation, these processes are best probed spectroscopically. About five-hundred orbits of the Hubble Space Telescope (HST) are being devoted in 2020-2022 to the ULLYSES public survey of about 70 low-mass (M, Comment: Accepted for publication on Astronomy & Astrophysics. 15 pages + appendix, language edited version

Published
2021

4. The GRAVITY Young Stellar Object survey. VII. The inner dusty disks of T Tauri stars

Author

A. Drescher, S. von Fellenberg, R. Garcia-Lopez, E. F. van Dishoeck, Lucas Labadie, Gilles Duvert, Christian Straubmeier, Myriam Benisty, Th. Henning, Jerome Bouvier, Stefan Gillessen, Sylvestre Lacour, Julia Stadler, T. Taro Shimizu, Silvia Scheithauer, Felix Widmann, Eckhard Sturm, P. Garciaınst, R. Grellmann, Laurent Jocou, Paola Caselli, Evelyne Alecian, Jean-Phillipe Berger, T. Ott, Z. Hubert, V. Lapeyrère, Eric Gendron, Frank Eisenhauer, Frederic H. Vincent, J. Sanchez-Bermudez, Andreas Eckart, A. Caratti o Garatti, A. P. Sousa, Pierre Léna, António Amorim, Natascha M. Förster-Schreiber, Pierre Kervella, L. Klarmann, Odele Straub, Dieter Lutz, J.-B. Le Bouquin, Thibaut Paumard, R. Genzel, Catherine Dougados, Y.-I. Bouarour, Yann Clénet, P. T. de Zeeuw, Wolfgang Brandner, Ric Davies, Jinyi Shangguan, Matthew Horrobin, Francois Menard, G. Heissel, Karine Perraut, Linda J. Tacconi, Guy Perrin, Stefan Hippler, 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 ), and 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)

Subjects
Gravity (chemistry), Techniques: Interferometric, Young stellar object, Continuum (design consultancy), FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Planet, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Techniques: High Angular Resolution, Infrared: ISM, Physics, Earth and Planetary Astrophysics (astro-ph.EP), [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 010308 nuclear & particles physics, Astronomy and Astrophysics, Radius, Astrophysics - Astrophysics of Galaxies, Accretion (astrophysics), Stars, T Tauri star, Instrumentation: High Angular Resolution, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Circumstellar Matter, Astrophysics::Earth and Planetary Astrophysics, Stars: Formation, Astrophysics - Earth and Planetary Astrophysics
Abstract

These protoplanetary disks in T Tauri stars play a central role in star and planet formation. We spatially resolve at sub-au scales the innermost regions of a sample of T Tauri's disks to better understand their morphology and composition. We extended our homogeneous data set of 27 Herbig stars and collected near-IR K-band observations of 17 T Tauri stars, spanning effective temperatures and luminosities in the ranges of ~4000-6000 K and ~0.4-10 Lsun. We focus on the continuum emission and develop semi-physical geometrical models to fit the interferometric data and search for trends between the properties of the disk and the central star. The best-fit models of the disk's inner rim correspond to wide rings. We extend the Radius-luminosity relation toward the smallest luminosities (0.4-10 Lsun) and find the R~L^(1/2) trend is no longer valid, since the K-band sizes measured with GRAVITY are larger than the predicted sizes from sublimation radius computation. No clear correlation between the K-band half-flux radius and the mass accretion rate is seen. Having magnetic truncation radii in agreement with the K-band GRAVITY sizes would require magnetic fields as strong as a few kG, which should have been detected, suggesting that accretion is not the main process governing the location of the half-flux radius of the inner dusty disk. Our measurements agree with models that take into account the scattered light. The N-to-K band size ratio may be a proxy for disentangling disks with silicate features in emission from disks with weak and/or in absorption silicate features. When comparing inclinations and PA of the inner disks to those of the outer disks (ALMA) in nine objects of our sample, we detect misalignments for four objects., Comment: Accepted for publication in A&A; 20 pages, 15 figures, 9 tables

Published
2021
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5. The GRAVITY Young Stellar Object survey VIII. Gas and dust faint inner rings in the hybrid disk of HD141569

Author

R. Grellmann, O. Pfuhl, V. Ganci, Eric Gendron, Feng Gao, Stefan Hippler, V. Coudé du Foresto, Guy Perrin, Gérard Rousset, Thibaut Paumard, Frederic H. Vincent, Catherine Dougados, A. Wojtczak, R. Genzel, A. Drescher, A. de Valon, Lucas Labadie, Gilles Duvert, E. F. van Dishoeck, G. Heissel, S. D. von Fellenberg, V. Lapeyrère, Mercedes E. Filho, Christian Straubmeier, Karine Perraut, Julia Stadler, Th. Henning, Paola Caselli, Felix Widmann, Z. Hubert, Stefan Gillessen, Matthew Horrobin, António Amorim, Odele Straub, R. Garcia Lopez, J.-B. Le Bouquin, L. Klarmann, Paulo J. V. Garcia, Jean-Phillipe Berger, G. Heißel, J. Sanchez-Bermudez, Andreas Eckart, Pierre Kervella, Silvia Scheithauer, Sylvestre Lacour, T. Ott, Frank Eisenhauer, Pierre Léna, T. Taro Shimizu, M. Bauböck, A. Caratti o Garatti, A. Jiménez-Rosales, Myriam Benisty, F. Eupen, Julien Woillez, Eckhard Sturm, Laurent Jocou, Wolfgang Brandner, Yann Clénet, P. T. de Zeeuw, and Jinyi Shangguan

Subjects
Physics, Protoplanetary disks, Earth and Planetary Astrophysics (astro-ph.EP), Young stellar object, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Planetary system, Stars, Infrared: planetary systems, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Techniques: interferometric, Radiative transfer, Spectral energy distribution, Astrophysics::Solar and Stellar Astrophysics, Emission spectrum, Astrophysics::Earth and Planetary Astrophysics, Spectral resolution, Stars: individual: HD 141569, Astrophysics::Galaxy Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Line (formation), Astrophysics - Earth and Planetary Astrophysics
Abstract

The formation and evolution of planetary systems impact the primordial accretion disk. HD141569 is the only known pre-main sequence star characterized by a hybrid disk. Observations probed the outer-disk structure showing a complex system of rings and interferometric observations attempted to characterize its inner 5 au region, but derived limited constraints. The goal of this work was to explore with new high-resolution interferometric observations the properties of the dust and gas in the internal regions of HD141569. We observed HD141569 on mas scales with GRAVITY/VLTI in the near-infrared at low and high spectral resolution. We interpreted the visibilities and spectral energy distribution with geometrical models and radiative transfer techniques to constrain the dust emission. We analyzed the high spectral resolution quantities to investigate the properties of the Br-Gamma line emitting region. Thanks to the combination of three different epochs, GRAVITY resolves the inner dusty disk in the K band. Data modeling shows that an IR excess of about 6% is spatially resolved and that the origin of this emission is confined in a ring of material located at a radius of 1 au from the star with a width smaller than 0.3 au. The MCMax modeling suggests that this emission could originate from a small amount of QHPs, while large silicate grain models cannot reproduce at the same time the observational constraints on the properties of near-IR and mid-IR fluxes. The differential phases in the Br-Gamma line clearly show an S-shape that can be best reproduced witha gas disk in Keplerian rotation, confined within 0.09 au. This is also hinted at by the double-peaked Br-Gamma emission line shape. The modeling of the continuum and gas emission shows that the inclination and position angle of these two components are consistent with a system showing relatively coplanar rings on all scales., Comment: Accepted for publication in A&A; 25 pages, 15 figures, 5 tables

Published
2021
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6. The GRAVITY young stellar object survey: III. The dusty disk of RY Lup

Author

Christian Straubmeier, V. Coudé du Foresto, T. Ott, Th. Henning, Guy Perrin, Z. Hubert, Frank Eisenhauer, E. F. van Dishoeck, Pierre Léna, Mercedes E. Filho, Stefan Hippler, Yann Clénet, P. T. de Zeeuw, O. Pfuhl, Odele Straub, J.-B. Le Bouquin, A. Caratti o Garatti, Karine Perraut, F. Vincent, Pierre Kervella, Eckhard Sturm, Julia Stadler, Feng Gao, Laurent Jocou, Catherine Dougados, Jinyi Shangguan, R. Genzel, R. Garcia-Lopez, M. Wiest, Thibaut Paumard, Gilles Duvert, Paola Caselli, Wing-Fai Thi, Wolfgang Brandner, Y.-I. Bouarour, Silvia Scheithauer, R. Grellmann, Francois Menard, S. D. von Fellenberg, Paulo J. V. Garcia, Stefan Gillessen, F. Eupen, Sylvestre Lacour, J. Sanchez-Bermudez, Andreas Eckart, Eric Gendron, A. Natta, Felix Widmann, Matthew Horrobin, Jean-Phillipe Berger, A. Jiménez-Rosales, L. Klarmann, Myriam Benisty, M. Bauböck, António Amorim, Lucas Labadie, Gérard Rousset, 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), Laboratoire Franco-Chilien d'Astronomie (LFCA), Universidad de Concepción [Chile]-Pontificia Universidad Católica de Chile (UC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Universidad de Chile, Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Gesellschaft, INAF - Osservatorio Astrofisico di Arcetri (OAA), Istituto Nazionale di Astrofisica (INAF), Leiden Observatory [Leiden], Universiteit Leiden [Leiden], Physikalisches Institut [Köln], Universität zu Köln, Faculty of Agronomy, University of Parakou, European Southern Observatory (ESO), SIM/IDL Faculdade de Ciências da Universidade de Lisboa (FCUL), University of Lisboa, 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), Max-Planck-Institut für Radioastronomie (MPIFR), Max Planck Institute for Extraterrestrial Physics (MPE), University of Brasilia [Brazil] (UnB), Universitat Politècnica de València (UPV), Galaxies, Etoiles, Physique, Instrumentation (GEPI), 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), Laboratoire Transport et Environnement (INRETS/LTE), Institut National de Recherche sur les Transports et leur Sécurité (INRETS), Swedish Space Corporation (SSC), HELMHOLTZ CENTRE FOR ENVIRONMENTAL RESEARCH UFZ HALLE SUR SAALE DEU, Partenaires IRSTEA, Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), Laboratoire Univers et Théories (LUTH (UMR_8102)), 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), GRAVITY Collaboration, 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, 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 [2007-2019] (Grenoble INP [2007-2019])-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 [2007-2019] (Grenoble INP [2007-2019])-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]), Centre National de la Recherche Scientifique (CNRS)-Universidad de Concepción [Chile]-Pontificia Universidad Católica de Chile (UC)-Universidad de Chile-Institut national des sciences de l'Univers (INSU - CNRS), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble [2020-....] (OSUG [2020-....]), 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 [2020-....] (UGA [2020-....])-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 [2020-....] (UGA [2020-....]), Environnement Ville Société (EVS), École normale supérieure - Lyon (ENS Lyon)-École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Université Lumière - Lyon 2 (UL2)-Université Jean Moulin - Lyon 3 (UJML), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université Jean Monnet [Saint-Étienne] (UJM)-École Nationale des Travaux Publics de l'État (ENTPE)-École nationale supérieure d'architecture de Lyon (ENSAL)-Centre National de la Recherche Scientifique (CNRS), Universitat Politecnica de Valencia (UPV), and 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)

Subjects
Young stellar object, variables, Extinction (astronomy), FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, stars: pre-main sequence, Herbig Ae/Be -stars, T Tauri, 01 natural sciences, circumstellar matter, Luminosity, stars: low-mass, stars: individual: RY Lup, protoplanetary disks -stars, 0103 physical sciences, low-mass, Astrophysics::Solar and Stellar Astrophysics, individual, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, Physics, stars: variables: T Tauri, Very Large Telescope, 010308 nuclear & particles physics, protoplanetary disks, Herbig Ae/Be, Astronomy and Astrophysics, Radius, Effective temperature, Astrophysics - Astrophysics of Galaxies, T Tauri star, Astrophysics - Solar and Stellar Astrophysics, [SDU]Sciences of the Universe [physics], 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), pre-main sequencestars, Spectral energy distribution, Astrophysics::Earth and Planetary Astrophysics, RY Lup -circumstellar matter -stars, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

We use PIONIER data from the ESO archive and GRAVITY data that were obtained in June 2017 with the four 8m telescopes. We use a parametric disk model and the 3D radiative transfer code MCFOST to reproduce the Spectral Energy Distribution and match the interferometric observations. To match the SED , our model requires a stellar luminosity of 2.5 Lsun, higher than any previously determined values. Such a high value is needed to accommodate the circumstellar extinction caused by the highly inclined disk, which has been neglected in previous studies. While using an effective temperature of 4800 K determined through high-resolution spectroscopy, we derive a stellar radius of 2.29 Rsun. These revised fundamental parameters, when combined with the mass estimates available , lead to an age of 0.5-2.0 Ma for RY Lup, in better agreement with the age of the Lupus association than previous determinations. Our disk model nicely reproduces the interferometric GRAVITY data and is in good agreement with the PIONIER ones. We derive an inner rim location at 0.12~au from the central star. This model corresponds to an inclination of the inner disk of 50deg, which is in mild tension with previous determinations of a more inclined outer disk from SPHERE (70 deg in NIR) and ALMA(67 $\pm$5 deg) images, but consistent with the inclination determination from the ALMA CO spectra (55$\pm$5deg). Increasing the inclination of the inner disk to 70 deg leads to a higher line-of-sight extinction and therefore requires a higher stellar luminosity of 4.65 Lsun to match the observed flux levels. This luminosity would translate to a stellar radius of 3.13~Rsun, leading to an age of 2-3~Ma, and a stellar mass of about 2 Msun, in disagreement with the observed dynamical mass estimate of 1.3-1.5 Msun. Critically, this high-inclination inner disk model also fails to reproduce the visibilities observed with GRAVITY., Accepted for publication in A&A; 11 pages, 5 figures, 3 tables

Published
2020
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7. Direct confirmation of the radial-velocity planet β Pictoris c

Author

Benjamin Charnay, Feng Gao, Antoine Mérand, L. Rodet, H. Bonnet, Tyler Gardner, Jean-Phillipe Berger, E. F. van Dishoeck, Anthony Boccaletti, Stefan Gillessen, Felix Widmann, Eric Gendron, Hervé Beust, Karine Perraut, Wolfgang Brandner, A. Cridland, J. Rameau, Sasha Hinkley, R. Asensio-Torres, Stefan Hippler, Roderick Dembet, Thibaut Paumard, John D. Monnier, Claudia Paladini, Valentin Christiaens, Julien Woillez, Linda J. Tacconi, Gilles Otten, Z. Hubert, V. Lapeyrère, Xavier Haubois, António Amorim, Guy Perrin, Jinyi Shangguan, Jingxiu Wang, R. Garcia Lopez, David Mouillet, Erich Wiezorrek, M. Nowak, Reinhard Genzel, Sylvestre Lacour, P. Rubini, G. Heißel, Gilles Duvert, Odele Straub, J.-B. Le Bouquin, Thomas Ott, Jens Kammerer, Anne-Lise Maire, A. Drescher, Laura Kreidberg, G. Rodríguez-Coira, O. Pfuhl, Paulo J. V. Garcia, Laurent Pueyo, A. Grandjean, Frank Eisenhauer, Yann Clénet, P. T. de Zeeuw, Pierre Léna, Matthew Horrobin, V. Coudé du Foresto, Roberto Abuter, Anne-Marie Lagrange, S. D. von Fellenberg, Tomas Stolker, Gérard Rousset, F. Vincent, Pierre Kervella, Faustine Cantalloube, Julien Girard, Andreas Eckart, Arthur Vigan, Mickael Bonnefoy, Paul Mollière, Silvia Scheithauer, André Müller, Miriam Keppler, Ekkehard Wieprecht, E. Nasedkin, Christian Straubmeier, Th. Henning, Jason Dexter, Sarah Blunt, Myriam Benisty, M. Houllé, K. Ward-Duong, Julia Stadler, A. Jiménez-Rosales, Eckhard Sturm, Laurent Jocou, M. Kulikauskas, M. Bauböck, Elodie Choquet, Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), 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), and Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)

Subjects
planets and satellites, Astrophysics, 01 natural sciences, Luminosity, formation -techniques, Planet, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, ComputingMilieux_MISCELLANEOUS, Physics, detection -planets and satellites, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010308 nuclear & particles physics, Planetary core, Giant planet, Astronomy and Astrophysics, Orbital period, Exoplanet, Accretion (astrophysics), Radial velocity, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], interferometric, Astrophysics::Earth and Planetary Astrophysics
Abstract

Context.Methods used to detect giant exoplanets can be broadly divided into two categories: indirect and direct. Indirect methods are more sensitive to planets with a small orbital period, whereas direct detection is more sensitive to planets orbiting at a large distance from their host star. This dichotomy makes it difficult to combine the two techniques on a single target at once.Aims.Simultaneous measurements made by direct and indirect techniques offer the possibility of determining the mass and luminosity of planets and a method of testing formation models. Here, we aim to show how long-baseline interferometric observations guided by radial-velocity can be used in such a way.Methods.We observed the recently-discovered giant planetβPictoris c with GRAVITY, mounted on the Very Large Telescope Interferometer.Results.This study constitutes the first direct confirmation of a planet discovered through radial velocity. We find that the planet has a temperature ofT = 1250 ± 50 K and a dynamical mass ofM = 8.2 ± 0.8 MJup. At 18.5 ± 2.5 Myr, this putsβPic c close to a ‘hot start’ track, which is usually associated with formation via disk instability. Conversely, the planet orbits at a distance of 2.7 au, which is too close for disk instability to occur. The low apparent magnitude (MK = 14.3 ± 0.1) favours a core accretion scenario.Conclusions.We suggest that this apparent contradiction is a sign of hot core accretion, for example, due to the mass of the planetary core or the existence of a high-temperature accretion shock during formation.

Published
2020
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8. Unveiling the β Pictoris system, coupling high contrast imaging, interferometric, and radial velocity data

Author

Christian Straubmeier, J. Hagelberg, Anne-Marie Lagrange, A. Grandjean, Frank Eisenhauer, Myriam Benisty, Silvano Desidera, R. Asensio-Torres, Anne-Lise Maire, M. Nowak, Thibaut Paumard, F. Cantalloube, Jens Kammerer, Yann Clénet, P. T. de Zeeuw, Matthew Horrobin, Karine Perraut, Eric Gendron, O. Pfuhl, L. Pueyo, Stefan Gillessen, Stefan Hippler, John Monnier, Raphael Galicher, P. Thebault, Gael Chauvin, C. Babusiaux, J. Wang, Wolfgang Brandner, L. Kreidberg, P. Léna, V. Lapeyrère, J. M. Girard, Sylvestre Lacour, G. Rodríguez-Coira, Guy Perrin, Matthew A. Kenworthy, H. Le Coroller, G. Heissel, F. Galland, V. Christiaens, P. Delorme, V. Coudé du Foresto, E. Choquet, Matthias Samland, Hervé Beust, Miriam Keppler, Odele Straub, Mickael Bonnefoy, Gilles Duvert, Andreas Eckart, Z. Wahhaj, T. Stolker, A. Zurlo, C. Paladini, F. Vincent, G. Otten, M. Janson, O. Flasseur, J.-B. Le Bouquin, A. Mérand, Felix Widmann, G. Rousset, Jinyi Shangguan, N. Meunier, Feng Gao, R. Gratton, A. Vigan, Paul Mollière, Jean-Phillipe Berger, P. Rubini, P. Kervella, T. Henning, António Amorim, T. Schmidt, Julien Woillez, Xavier Haubois, Anthony Boccaletti, Maud Langlois, Q. Kral, P. Garcia, Thomas Ott, L. Rodet, B. Charnay, R. Garcia Lopez, Reinhard Genzel, Sergio Messina, 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, 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 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, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), 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 Paris Cité (UPCité), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), 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), Galaxies, Etoiles, Physique, Instrumentation (GEPI), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), European Southern Observatory [Santiago] (ESO), European Southern Observatory (ESO), CENTRA-SIM, IDL-Faculdade de Ciencias da Universidade de Lisboa, Departamento de Astronomía, Universidad de Chile = University of Chile [Santiago] (UCHILE), Max-Planck-Institut für Radioastronomie (MPIFR), Max Planck Institute for Extraterrestrial Physics (MPE), Max-Planck-Gesellschaft, CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire des Combustibles Uranium (LCU), Service d'Analyses, d'Elaboration, d'Expérientations et d'Examens des combustibles (SA3E), Département d'Etudes des Combustibles (DEC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Département d'Etudes des Combustibles (DEC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / 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-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Physikalisches Institut [Köln], Universität zu Köln = University of Cologne, Max-Planck-Institut für Astronomie (MPIA), University of Freiburg [Freiburg], Space Telescope Science Institute (STSci), German Research Centre for Geosciences - Helmholtz-Centre Potsdam (GFZ), Astronomical Institute Anton Pannekoek (AI PANNEKOEK), University of Amsterdam [Amsterdam] (UvA), the GRAVITY Collaboration, 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)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), 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), Centre d'Immunologie de Marseille - Luminy (CIML), Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Observatoire de Paris - Site de Paris (OP), Universität zu Köln, 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 de Recherche pour le Développement (IRD), and Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)

Subjects
planets and satellites: detection, media_common.quotation_subject, Context (language use), Astrophysics, 01 natural sciences, Planet, radial velocities -planets and satellites, 0103 physical sciences, techniques: radial velocities, Astrophysics::Solar and Stellar Astrophysics, Eccentricity (behavior), 10. No inequality, planets and satellites: fundamental parameters, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, media_common, Orbital elements, Physics, [PHYS]Physics [physics], detectionplanets and satellites, 010308 nuclear & particles physics, high angular resolution -techniques, Giant planet, techniques: high angular resolution, Astronomy and Astrophysics, Astrometry, Planetary system, Radial velocity, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], techniques, fundamental parameters
Abstract

Context. The nearby and young β Pictoris system hosts a well resolved disk, a directly imaged massive giant planet orbiting at ≃9 au, as well as an inner planet orbiting at ≃2.7 au, which was recently detected through radial velocity (RV). As such, it offers several unique opportunities for detailed studies of planetary system formation and early evolution. Aims. We aim to further constrain the orbital and physical properties of β Pictoris b and c using a combination of high contrast imaging, long base-line interferometry, and RV data. We also predict the closest approaches or the transit times of both planets, and we constrain the presence of additional planets in the system. Methods. We obtained six additional epochs of SPHERE data, six additional epochs of GRAVITY data, and five additional epochs of RV data. We combined these various types of data in a single Markov-chain Monte Carlo analysis to constrain the orbital parameters and masses of the two planets simultaneously. The analysis takes into account the gravitational influence of both planets on the star and hence their relative astrometry. Secondly, we used the RV and high contrast imaging data to derive the probabilities of presence of additional planets throughout the disk, and we tested the impact of absolute astrometry. Results. The orbital properties of both planets are constrained with a semi-major axis of 9.8 ± 0.4 au and 2.7 ± 0.02 au for b and c, respectively, and eccentricities of 0.09 ± 0.1 and 0.27 ± 0.07, assuming the HIPPARCOS distance. We note that despite these low fitting error bars, the eccentricity of β Pictoris c might still be over-estimated. If no prior is provided on the mass of β Pictoris b, we obtain a very low value that is inconsistent with what is derived from brightness-mass models. When we set an evolutionary model motivated prior to the mass of β Pictoris b, we find a solution in the 10–11 MJup range. Conversely, β Pictoris c’s mass is well constrained, at 7.8 ± 0.4 MJup, assuming both planets are on coplanar orbits. These values depend on the assumptions on the distance of the β Pictoris system. The absolute astrometry HIPPARCOS-Gaia data are consistent with the solutions presented here at the 2σ level, but these solutions are fully driven by the relative astrometry plus RV data. Finally, we derive unprecedented limits on the presence of additional planets in the disk. We can now exclude the presence of planets that are more massive than about 2.5 MJup closer than 3 au, and more massive than 3.5 MJup between 3 and 7.5 au. Beyond 7.5 au, we exclude the presence of planets that are more massive than 1–2 MJup. Conclusions. Combining relative astrometry and RVs allows one to precisely constrain the orbital parameters of both planets and to give lower limits to potential additional planets throughout the disk. The mass of β Pictoris c is also well constrained, while additional RV data with appropriate observing strategies are required to properly constrain the mass of β Pictoris b.

Published
2020
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9. A measure of the size of the magnetospheric accretion region in TW Hydrae

Author

Pierre Kervella, Y. Clénet, M. Filho, Stefan Hippler, Wolfgang Brandner, Tom Ray, Ekkehard Wieprecht, S. Yazici, S. von Fellenberg, O. Pfuhl, M. Bauboeck, J. Sanchez-Bermudez, Andreas Eckart, C. E. Garcia Dabo, A. Ramirez, R. Fedriani, Maryam Habibi, Paulo J. V. Garcia, F. H. Vincent, M. Koutoulaki, António Amorim, Julia Stadler, T. de Zeeuw, A. Jimenez Rosales, Feng Gao, Catherine Dougados, Felix Widmann, Karine Perraut, Lucas Labadie, Myriam Benisty, R. Garcia Lopez, Reinhard Genzel, H. Bonnet, A. Buron, E. F. van Dishoeck, Silvia Scheithauer, W. J. de Wit, Jinyi Shangguan, Stefan Gillessen, T. Ott, Frank Eisenhauer, T. Paumard, Sylvestre Lacour, Pierre Léna, V. Coudé du Foresto, Matthew Horrobin, Julien Woillez, Jean-Philippe Berger, F. Haussmann, A. Natta, L. Klarmann, Z. Hubert, Odele Straub, J.-B. Le Bouquin, Johann Kolb, Erich Wiezorrek, Eckhard Sturm, Laurent Jocou, Guy Perrin, A. Caratti o Garatti, R. Grellmann, Eric Gendron, Christian Straubmeier, Th. Henning, C. Rau, Xavier Haubois, M. Wiest, Roberto Abuter, Gilles Duvert, Paola Caselli, Gérard Zins, G. Rousset, 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), School of Cosmic Physics [Dublin], and Dublin Institute for Advanced Studies (DIAS)

Subjects
Young stellar object, Astrophysics::High Energy Astrophysical Phenomena, Magnetosphere, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, 0103 physical sciences, TW Hydrae, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, Physics, Multidisciplinary, 010308 nuclear & particles physics, Stellar magnetic field, Radius, Accretion (astrophysics), Stars, T Tauri star, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, [SDU]Sciences of the Universe [physics], Astrophysics::Earth and Planetary Astrophysics
Abstract

Stars form by accreting material from their surrounding disks. There is a consensus that matter flowing through the disk is channelled onto the stellar surface by the stellar magnetic field. This is thought to be strong enough to truncate the disk close to the so-called corotation radius where the disk rotates at the same rate as the star. Spectro-interferometric studies in young stellar objects show that Hydrogen is mostly emitted in a region of a few milliarcseconds across, usually located within the dust sublimation radius. Its origin is still a matter of debate and it can be interpreted as coming from the stellar magnetosphere, a rotating wind or a disk. In the case of intermediate-mass Herbig AeBe stars, the fact that the Br gamma emission is spatially resolved rules out that most of the emission comes from the magnetosphere. This is due to the weak magnetic fields (some tenths of G) detected in these sources, resulting in very compact magnetospheres. In the case of T Tauri sources, their larger magnetospheres should make them easier to resolve. However, the small angular size of the magnetosphere (a few tenths of milliarcseconds), along with the presence of winds emitting in Hydrogen make the observations interpretation challenging. Here, we present direct evidence of magnetospheric accretion by spatially resolving the inner disk of the 60 pc T Tauri star TW Hydrae through optical long baseline interferometry. We find that the hydrogen near-infrared emission comes from a region approximately 3.5 stellar radii (R*) across. This region is within the continuum dusty disk emitting region (Rcont = 7 R*) and smaller than the corotation radius which is twice as big. This indicates that the hydrogen emission originates at the accretion columns, as expected in magnetospheric accretion models, rather than in a wind emitted at much larger distance (>1au)., Publish in Nature

Published
2020
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10. The GRAVITY young stellar object survey. II. First spatially resolved observations of the CO bandhead emission in a high-mass YSO

Author

E. F. van Dishoeck, Feng Gao, Lucas Labadie, Wing-Fai Thi, Catherine Dougados, R. Fedriani, Paulo J. V. Garcia, Stefan Gillessen, Matthew Horrobin, Christian Straubmeier, J. Sanchez-Bermudez, Frederic H. Vincent, L. Klarmann, Th. Henning, Gérard Rousset, Eckhard Sturm, Laurent Jocou, Andreas Eckart, Thibaut Paumard, R. Grellmann, A. Caratti o Garatti, Arjan Bik, T. Ott, Odele Straub, Bernard Lazareff, V. Coudé du Foresto, Frank Eisenhauer, H. Linz, J.-B. Le Bouquin, Eric Gendron, António Amorim, Tom Ray, Jean-Phillipe Berger, Pierre Léna, Paola Caselli, Silvia Scheithauer, Sylvestre Lacour, Felix Widmann, Paulo Gordo, Gilles Duvert, R. Garcia Lopez, Reinhard Genzel, Guy Perrin, J. Stadler, Pierre Kervella, Karine Perraut, M. Koutoulaki, Myriam Benisty, Wolfgang Brandner, Yann Clénet, P. T. de Zeeuw, Jinyi Shangguan, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), 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)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)

Subjects
stars, 010504 meteorology & atmospheric sciences, Stellar mass, Gaussian, Young stellar object, Overtone, FOS: Physical sciences, Astrophysics, 01 natural sciences, symbols.namesake, formation -stars, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, observational, massive -infrared, 010303 astronomy & astrophysics, infrared: stars, Astrophysics::Galaxy Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, Physics, [PHYS]Physics [physics], stars: formation, Astronomy and Astrophysics, Position angle, Ellipsoid, Astrophysics - Astrophysics of Galaxies, stars: massive, Interferometry, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, techniques: interferometric, interferometric -techniques, [SDU]Sciences of the Universe [physics], Astrophysics of Galaxies (astro-ph.GA), Closure phase, symbols, Astrophysics::Earth and Planetary Astrophysics, methods: observational, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], techniques: spectroscopic, stars -techniques, spectroscopicmethods
Abstract

The inner regions of the discs of high-mass young stellar objects (HMYSOs) are still poorly known due to the small angular scales and the high visual extinction involved. We deploy near-infrared (NIR) spectro-interferometry to probe the inner gaseous disc in HMYSOs and investigate the origin and physical characteristics of the CO bandhead emission (2.3-2.4 $\mu$m). We present the first GRAVITY/VLTI observations at high spectral (R=4000) and spatial (mas) resolution of the CO overtone transitions in NGC 2024 IRS2. The continuum emission is resolved in all baselines and is slightly asymmetric, displaying small closure phases ($\leq$8$^{\circ}$). Our best ellipsoid model provides a disc inclination of 34$^{\circ}$$\pm$1$^{\circ}$, a disc major axis position angle of 166$^{\circ}$$\pm$1$^{\circ}$, and a disc diameter of 3.99$\pm$0.09 mas (or 1.69$\pm$0.04 au, at a distance of 423 pc). The small closure phase signals in the continuum are modelled with a skewed rim, originating from a pure inclination effect. For the first time, our observations spatially and spectrally resolve the first four CO bandheads. Changes in visibility, as well as differential and closure phases across the bandheads are detected. Both the size and geometry of the CO-emitting region are determined by fitting a bidimensional Gaussian to the continuum-compensated CO bandhead visibilities. The CO-emitting region has a diameter of 2.74$\pm^{0.08}_{0.07}$ mas (1.16$\pm$0.03 au), and is located in the inner gaseous disc, well within the dusty rim, with inclination and $PA$ matching the dusty disc geometry, which indicates that both dusty and gaseous discs are coplanar. Physical and dynamical gas conditions are inferred by modelling the CO spectrum. Finally, we derive a direct measurement of the stellar mass of $M_*\sim$14.7$^{+2}_{-3.6}$ M$_{\odot}$ by combining our interferometric and spectral modelling results., Comment: Accepted for publication in A&A letters

Published
2020
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11. The GRAVITY young stellar object survey

Author

A. Caratti o Garatti, R. Fedriani, R. Garcia Lopez, M. Koutoulaki, K. Perraut, H. Linz, W. Brandner, P. Garcia, L. Klarmann, T. Henning, L. Labadie, J. Sanchez-Bermudez, B. Lazareff, E. F. van Dishoeck, P. Caselli, P. T. de Zeeuw, A. Bik, M. Benisty, C. Dougados, T. P. Ray, A. Amorim, J.-P. Berger, Y. Clénet, V. Coudé du Foresto, G. Duvert, A. Eckart, F. Eisenhauer, F. Gao, E. Gendron, and R. Genzel

Published
2020
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12. Peering into the formation history of β Pictoris b with VLTI/GRAVITY long-baseline interferometry

Author

Gérard Rousset, N. M. Förster Schreiber, E. F. van Dishoeck, Laurent Pueyo, Frank Eisenhauer, Pierre Léna, H. Bonnet, Jingxiu Wang, Eric Gendron, Stefan Gillessen, Anne-Lise Maire, Yann Clénet, P. T. de Zeeuw, Hervé Beust, Jinyi Shangguan, S. Yazici, Julien Woillez, Thibaut Paumard, Claudia Paladini, C. Collin, M. Nowak, Sylvestre Lacour, Thomas Ott, D. Ziegler, F. Chapron, António Amorim, Erich Wiezorrek, Oliver Pfuhl, Feng Gao, A. Buron, P. Fédou, Z. Hubert, R. Garcia Lopez, Reinhard Genzel, Wolfgang Brandner, Odele Straub, J.-B. Le Bouquin, Ekkehard Wieprecht, Jean-Phillipe Berger, Stefan Hippler, Benjamin Charnay, Eckhard Sturm, F. Vincent, Pierre Kervella, Faustine Cantalloube, Laurent Jocou, G. Rodríguez-Coira, Sebastian Rabien, Roberto Abuter, Anne-Marie Lagrange, Mickael Bonnefoy, C. Rau, Linda J. Tacconi, Guy Perrin, Andreas Eckart, Silvia Scheithauer, Felix Widmann, Karine Perraut, V. Lapeyrère, P. Mollière, Gilles Duvert, Christian Straubmeier, F. Haußmann, Th. Henning, Jason Dexter, V. Coudé du Foresto, R. Dembet, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), 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)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)

Subjects
Planetesimal, 010504 meteorology & atmospheric sciences, planets and satellites, formation -planets and satellites, atmospheres -techniques, FOS: Physical sciences, Context (language use), Astrophysics, 01 natural sciences, β Pictoris, Planet, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, individual, 010303 astronomy & astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Orbital elements, Physics, [PHYS]Physics [physics], Earth and Planetary Astrophysics (astro-ph.EP), Very Large Telescope, Giant planet, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy and Astrophysics, Astrometry, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Astrophysics::Earth and Planetary Astrophysics, interferometricstars, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Instrumentation and Methods for Astrophysics, Planetary mass, Astrophysics - Earth and Planetary Astrophysics
Abstract

Our objective is to estimate the C/O ratio in the atmosphere of beta Pictoris b and obtain an estimate of the dynamical mass of the planet, as well as to refine its orbital parameters using high-precision astrometry. We used the GRAVITY instrument with the four 8.2 m telescopes of the Very Large Telescope Interferometer to obtain K-band spectro-interferometric data on $\beta$ Pic b. We extracted a medium resolution (R=500) K-band spectrum of the planet and a high-precision astrometric position. We estimated the planetary C/O ratio using two different approaches (forward modeling and free retrieval) from two different codes (ExoREM and petitRADTRANS, respectively). Finally, we used a simplified model of two formation scenarios (gravitational collapse and core-accretion) to determine which can best explain the measured C/O ratio. Our new astrometry disfavors a circular orbit for $\beta$ Pic b ($e=0.15^{+0.05}_{-0.04}$). Combined with previous results and with Hipparcos/GAIA measurements, this astrometry points to a planet mass of $M = 12.7\pm{}2.2\,M_\mathrm{Jup}$. This value is compatible with the mass derived with the free-retrieval code petitRADTRANS using spectral data only. The forward modeling and free-retrieval approches yield very similar results regarding the atmosphere of beta Pic b. In particular, the C/O ratios derived with the two codes are identical ($0.43\pm{}0.05$ vs $0.43^{+0.04}_{-0.03}$). We argue that if the stellar C/O in $\beta$ Pic is Solar, then this combination of a very high mass and a low C/O ratio for the planet suggests a formation through core-accretion, with strong planetesimal enrichment., Comment: 14 pages + 7 page appendix, 7 figures, accepted for pulication

Published
2020
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13. Mirror, mirror on the outflow cavity wall. Near-infrared CO overtone disc emission of the high-mass YSO IRAS 11101-5829

Author

Rene D. Oudmaijer, R. Cesaroni, M. Koutoulaki, R. Garcia-Lopez, Bringfried Stecklum, Deirdre Coffey, A. Natta, A. Caratti o Garatti, Thomas P. Ray, and R. Fedriani

Subjects
Accretion, Thermodynamic equilibrium, Young stellar object, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Jets and outflows, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, 01 natural sciences, Massive stars, Coincident, 0103 physical sciences, Protostar, Astrophysics::Solar and Stellar Astrophysics, IRAS 11101-5829, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Physics, 010308 nuclear & particles physics, Near-infrared spectroscopy, Astronomy and Astrophysics, HH 135-HH 136, Astrophysics - Astrophysics of Galaxies, Accretion (astrophysics), Protostars, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Outflow, Astrophysics::Earth and Planetary Astrophysics, Cavity wall, Accretion discs
Abstract

Aims: The inner regions of high-mass protostars are often invisible in the near-infrared. We aim to investigate the inner gaseous disc of IRAS11101-5829 through scattered light from the outflow cavity walls. Methods: We observed the environment of the high-mass young stellar object IRAS11101-5829 and the closest knots of its jet, HH135-136, with the VLT/SINFONI. We also retrieved archival data from the high-resolution long-slit spectrograph VLT/X-shooter. Results: We detect the first three bandheads of the $\upsilon=2-0$ CO vibrational emission for the first time in this object. It is coincident with continuum and Br$\gamma$ emission and extends up to $\sim10000$ au to the north-east and $\sim10 000$ au to the south-west. The line profiles have been modelled as a Keplerian rotating disc assuming a single ring in LTE. The model output gives a temperature of $\sim3000$ K, a CO column density of $\sim1\times10^{22}\mathrm{ cm^{-2}}$, and a projected Keplerian velocity $v_\mathrm{K}\sin i_\mathrm{disc} \sim 25\mathrm{ km s^{-1}}$, which is consistent with previous modelling in other high-mass protostars. In particular, the low value of $v_\mathrm{K}\sin i_\mathrm{disc}$ suggests that the disc is observed almost face-on, whereas the well-constrained geometry of the jet imposes that the disc must be close to edge-on. This apparent discrepancy is interpreted as the CO seen reflected in the mirror of the outflow cavity wall. Conclusions: From both jet geometry and disc modelling, we conclude that all the CO emission is seen through reflection by the cavity walls and not directly. This result implies that in the case of highly embedded objects, as for many high-mass protostars, line profile modelling alone might be deceptive and the observed emission could affect the derived physical and geometrical properties; in particular the inclination of the system can be incorrectly interpreted., Comment: 11 pages, 10 figures

Published
2020
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14. The GRAVITY young stellar object survey

Author

Y.-I. Bouarour, K. Perraut, F. Ménard, W. Brandner, A. Caratti o Garatti, P. Caselli, E. van Dishoeck, C. Dougados, R. Garcia-Lopez, R. Grellmann, T. Henning, L. Klarmann, L. Labadie, A. Natta, J. Sanchez-Bermudez, W.-F. Thi, P. T. de Zeeuw, A. Amorim, M. Bauböck, M. Benisty, J.-P. Berger, Y. Clenet, V. Coudé du Foresto, G. Duvert, A. Eckart, F. Eisenhauer, F. Eupen, M. Filho, F. Gao, P. Garcia

Published
2020
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15. The GRAVITY young stellar object survey

Author

Paola Caselli, E. F. van Dishoeck, Feng Gao, Jaime E. Pineda, Karine Perraut, Lucas Labadie, Stefan Gillessen, Catherine Dougados, Felix Widmann, E. Sturm, Odele Straub, Eric Gendron, J.-B. Le Bouquin, Christian Straubmeier, L. Klarmann, Mercedes E. Filho, A. Eckart, Thomas Ott, J. Sanchez-Bermudez, Th. Henning, A. Drescher, V. Lapeyrère, Gérard Rousset, Zoltan Hubert, Matthew Horrobin, Paulo J. V. Garcia, Gilles Duvert, Julien Woillez, G. Heissel, Thibaut Paumard, Jean-Phillipe Berger, G. Rodríguez-Coira, R. Grellmann, Frederic H. Vincent, Laurent Jocou, J. Stadler, S. D. von Fellenberg, Sylvestre Lacour, António Amorim, Guy Perrin, Pierre Kervella, V. Coudé du Foresto, Frank Eisenhauer, R. Garcia Lopez, Reinhard Genzel, Dominique Segura-Cox, Pierre Léna, M. Bauböck, Myriam Benisty, T. Taro Shimizu, A. Caratti o Garatti, A. Jiménez-Rosales, Yann Clénet, P. T. de Zeeuw, Wolfgang Brandner, and Jinyi Shangguan

Subjects
Young stellar object, FOS: Physical sciences, Context (language use), Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, 01 natural sciences, Planet, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Angular resolution, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, Earth and Planetary Astrophysics (astro-ph.EP), Physics, Very Large Telescope, 010308 nuclear & particles physics, Astronomy and Astrophysics, Accretion (astrophysics), Vortex, Stars, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

Protoplanetary disks drive some of the formation process (e.g., accretion, gas dissipation, formation of structures, etc.) of stars and planets. Understanding such physical processes is one of the main astrophysical questions. HD 163296 is an interesting young stellar object for which infrared and sub-millimeter observations have shown a prominent circumstellar disk with gaps plausibly created by forming planets. This study aims at characterizing the morphology of the inner disk in HD 163296 with multi-epoch near-infrared interferometric observations performed with GRAVITY at the Very Large Telescope Interferometer (VLTI). Our goal is to depict the K-band (lambda_0 ~ 2.2 um) structure of the inner rim with milliarcsecond (sub-au) angular resolution. Our data is complemented with archival PIONIER (H-band; lambda_0 ~ 1.65 um) data of the source. We performed a Gradient Descent parametric model fitting to recover the sub-au morphology of our source. Our analysis shows the existence of an asymmetry in the disk surrounding the central star of HD 163296. We confirm variability of the disk structure in the inner ~2 mas (0.2 au). While variability of the inner disk structure in this source has been suggested by previous interferometric studies, this is the first time that it is confirmed in the H- and K-bands by using a complete analysis of the closure phases and squared visibilities over several epochs. Because of the separation from the star, position changes, and persistence of this asymmetric structure on timescales of several years, we argue that it is a dusty feature (e.g., a vortex or dust clouds), probably, made by a mixing of sillicate and carbon dust and/or refractory grains, inhomogeneously distributed above the mid-plane of the disk., Accepted to be published in Astronomy and Astrophysics; main-body: 11 pages, 3 figures and 3 tables

Published
2021
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16. The GRAVITY Young Stellar Object survey I. Probing the disks of Herbig Ae/Be stars in terrestrial orbits

Author

S. Yazici, Oliver Pfuhl, Thomas Henning, J. Bouvier, Stefan Hippler, V. Coudé du Foresto, Thomas Ott, J. Sanchez-Bermudez, Lucas Labadie, E. F. van Dishoeck, Myriam Benisty, Sebastian Rabien, Stefan Gillessen, Frank Eisenhauer, Frederic H. Vincent, A. Caratti o Garatti, Karine Perraut, Chien-Cheng Lin, Laurent Jocou, Andreas Eckart, Jaime E. Pineda, Matthew Horrobin, Christian Straubmeier, Roberto Abuter, Idel Waisberg, Feng Gao, L. Klarmann, Catherine Dougados, Imke Wank, Antoine Mérand, C. Rau, Gérard Rousset, Felix Widmann, Sarah Kendrew, Guy Perrin, A. Buron, P. T. de Zeeuw, Thomas P. Ray, R. Grellmann, Wolfgang Brandner, António Amorim, Bernard Lazareff, Dominique Segura-Cox, Paulo Gordo, Erich Wiezorrek, Henri Bonnet, F. Eupen, Eric Gendron, F. Haussmann, M. Koutoulaki, Yann Clénet, Silvia Scheithauer, Xavier Haubois, Paola Caselli, M. Wiest, Paulo J. V. Garcia, Gilles Duvert, Reinhard Genzel, Julien Woillez, Thibaut Paumard, E. Sturm, Jason Dexter, Jean-Philippe Berger, Z. Hubert, Sylvestre Lacour, Odele Straub, J.-B. Le Bouquin, Pierre Léna, R. Garcia-Lopez, Ekkehard Wieprecht, Pierre Kervella, Faustine Cantalloube, 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, and 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)

Subjects
stars, Young stellar object, Population, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Planet, 0103 physical sciences, Thermal, Astrophysics::Solar and Stellar Astrophysics, high angular resolutiontechniques, education, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, Physics, Earth and Planetary Astrophysics (astro-ph.EP), education.field_of_study, Very Large Telescope, 010308 nuclear & particles physics, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Stars, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Astrophysics of Galaxies (astro-ph.GA), formation -circumstellar matter -infrared, interferometric, Closure phase, Terrestrial planet, Astrophysics::Earth and Planetary Astrophysics, ISM -techniques, Astrophysics - Earth and Planetary Astrophysics
Abstract

The formation and the evolution of protoplanetary disks are important stages in the lifetime of stars. The processes of disk evolution and planet formation are intrinsically linked. We spatially resolve with GRAVITY/VLTI in the K-band the sub au-scale region of 27 stars to gain statistical understanding of their properties. We look for correlations with stellar parameters, such as luminosity, mass, temperature and age. Our sample also cover a range of various properties in terms of reprocessed flux, flared or flat morphology, and gaps. We developed semi-physical geometrical models to fit our interferometric data. Our best models correspond to smooth and wide rings, implying that wedge-shaped rims at the dust sublimation edge are favored, as found in the H-band. The closure phases are generally non-null with a median value of ~10 deg, indicating spatial asymmetries of the intensity distributions. Multi-size grain populations could explain the closure phase ranges below 20-25 deg but other scenarios should be invoked to explain the largest ones. Our measurements extend the Radius-Luminosity relation to ~1e4 Lsun and confirm the significant spread around the mean relation observed in the H-band. Gapped sources exhibit a large N-to-K band size ratio and large values of this ratio are only observed for the members of our sample that would be older than 1 Ma, less massive, and with lower luminosity. In the 2 Ms mass range, we observe a correlation in the increase of the relative age with the transition from group II to group I, and an increase of the N-to-K size ratio. However, the size of the current sample does not yet permit us to invoke a clear universal evolution mechanism across the HAeBe mass range. The measured locations of the K-band emission suggest that these disks might be structured by forming young planets, rather than by depletion due to EUV, FUV, and X-ray photo-evaporation., Comment: Accepted for publication in A&A; 23 pages, 16 figures, 7 tables

Published
2019
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17. Measuring the ionisation fraction in a jet from a massive protostar

Author

Thomas P. Ray, Jonathan C. Tan, Deirdre Coffey, A. Caratti o Garatti, Melvin Hoare, S. J. D. Purser, R. Garcia-Lopez, Bringfried Stecklum, R. Fedriani, and Alberto Sanna

Subjects
0301 basic medicine, Angular momentum, Infrared, Science, Astrophysics::High Energy Astrophysical Phenomena, General Physics and Astronomy, FOS: Physical sciences, 02 engineering and technology, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Article, General Biochemistry, Genetics and Molecular Biology, Stellar evolution, 03 medical and health sciences, Interstellar medium, Ionization, Protostar, Astrophysics::Solar and Stellar Astrophysics, lcsh:Science, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, Physics, Solar mass, Multidisciplinary, General Chemistry, 021001 nanoscience & nanotechnology, Publisher Correction, Stars, Astrophysics - Astrophysics of Galaxies, Accretion (astrophysics), 030104 developmental biology, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Astronomy and astrophysics, Astrophysics of Galaxies (astro-ph.GA), Mass spectrum, lcsh:Q, Astrophysics::Earth and Planetary Astrophysics, 0210 nano-technology
Abstract

It is important to determine if massive stars form via disc accretion, like their low-mass counterparts. Theory and observation indicate that protostellar jets are a natural consequence of accretion discs and are likely to be crucial for removing angular momentum during the collapse. However, massive protostars are typically rarer, more distant and more dust enshrouded, making observational studies of their jets more challenging. A fundamental question is whether the degree of ionisation in jets is similar across the mass spectrum. Here we determine an ionisation fraction of $\sim5-12\%$ in the jet from the massive protostar G35.20-0.74N, based on spatially coincident infrared and radio emission. This is similar to the values found in jets from lower-mass young stars, implying a unified mechanism of shock ionisation applies in jets across most of the protostellar mass spectrum, up to at least $\sim10$ solar masses., Comment: Published in Nature Communications. This is author's version. Full article is available here https://rdcu.be/bN6ps . 10 pages, 4 Figures, including methods and references

Published
2019

18. First direct detection of an exoplanet by optical interferometry

Author

S. Lacour, M. Nowak, J. Wang, O. Pfuhl, F. Eisenhauer, R. Abuter, A. Amorim, N. Anugu, M. Benisty, J. P. Berger, H. Beust, N. Blind, M. Bonnefoy, H. Bonnet, P. Bourget, W. Brandner, A. Buron, C. Collin, B. Charnay, F. Chapron, Y. Clénet, V. Coudé du Foresto, P. T. de Zeeuw, C. Deen, R. Dembet, J. Dexter, G. Duvert, A. Eckart, N. M. Förster Schreiber, P. Fédou, P. Garcia, R. Garcia Lopez, and F. Ga

Published
2019
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19. GIARPS/GRAVITY Survey: Broad-Band 0.44–2.4 Micron High-Resolution Spectra of T-Tauri and Herbig AeBe Stars – Combining High Spatial and High Spectral Resolution Data to Unveil the Inner Disc Physics

Author

A. Natta, Jan Brand, S. Casu, Catherine Dougados, Wolfgang Brandner, A. Giannetti, R. Garcia Lopez, Marco Pedani, F. Massi, Nicoletta Sanna, Luca Moscadelli, Deirdre Coffey, Lucas Labadie, Karine Perraut, Alberto Sanna, Tom Ray, S. Leurini, A. Caratti o Garatti, Myriam Benisty, ITA, FRA, DEU, and IRL

Subjects
Physics, Stars, T Tauri star, Gravity (chemistry), Spectrometer, Young stellar object, Astrophysics, Spectral resolution, Accretion (astrophysics), Spectral line
Abstract

The GIARPS/GRAVITY survey aims to obtain a set of high spatial and spectral resolution data for a sample of T-Tauri and Herbig AeBe stars (∼100 objects) selected from the VLTI/GRAVITY GTO sample of Young Stellar Objects (YSOs). GIARPS is a broad-band spectrometer combining HARPS-N and GIANO which allows high-resolution spectra from 0.44 μm (R ∼ 115, 000) to 2.44 μm (R ∼ 50, 000) in one observation. By combining this high spectral resolution with the high spatial resolution (∼1 mas) of GRAVITY, a view of unprecedented detail can be obtained of the innermost regions of circumstellar discs in YSOs spanning a wide range of masses (0.1–5 M⊙) and ages (105–107 yr). The ultimate goal is to model the accretion and ejection mechanisms, and study how they evolve as a function of YSO mass and age, using the spatially and spectrally resolved atomic and molecular lines from the inner gaseous regions.

Published
2019
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20. Launching the asymmetric bipolar jet of DO Tau

Author

Davide Fedele, Catherine Dougados, Deirdre Coffey, R. Garcia-Lopez, J. Erkal, Francesca Bacciotti, Antonio Chrysostomou, Sylvie Cabrit, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), 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)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)

Subjects
Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, stars: pre-main sequence, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Rotation, 01 natural sciences, stars: low-mass, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), [PHYS]Physics [physics], Physics, Jet (fluid), ISM: individual objects: DO Tau, 010308 nuclear & particles physics, Star formation, Astronomy and Astrophysics, Radius, Radial velocity, T Tauri star, ISM: jets and outflows, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Orbital motion, Precession, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

The role of bipolar jets in the formation of stars, and in particular how they are launched, is still not well understood. We probe the protostellar jet launching mechanism, via high resolution observations of the near-IR [FeII] 1.53,1.64 micron lines. We consider the bipolar jet from the Classical T Tauri star, DO Tau, & investigate jet morphology & kinematics close to the star, using AO-assisted IFU observations from GEMINI/NIFS. The brighter, blue-shifted jet is collimated quickly after launch. This early collimation requires the presence of magnetic fields. We confirm velocity asymmetries between the two jet lobes, & confirm no time variability in the asymmetry over a 20 year interval. This sustained asymmetry is in accordance with recent simulations of magnetised disk-winds. We examine the data for jet rotation. We report an upper limit on differences in radial velocity of 6.3 & 8.7 km/s for the blue & red-shifted jets, respectively. Interpreting this as an upper limit on jet rotation implies that any steady, axisymmetric magneto-centrifugal model of jet launching is constrained to a launch radius in the disk-plane of 0.5 & 0.3 au for the blue & red-shifted jets, respectively. This supports an X-wind or narrow disk-wind model. This pertains only to the observed high velocity [FeII] emission, & does not rule out a wider flow launched from a wider radius. We report detection of small amplitude jet axis wiggling in both lobes. We rule out orbital motion of the jet source as the cause. Precession can better account for the observations but requires double the precession angle, & a different phase for the counter-jet. Such non-solid body precession could arise from an inclined massive Jupiter companion, or a warping instability induced by launching a magnetic disk-wind. Overall, our observations are consistent with an origin of the DO Tau jets from the inner regions of the disk., Accepted for publication in A&A - 18 pages, 11 figures (incl. Appendix)

Published
2021
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21. Retrieving scattering clouds and disequilibrium chemistry in the atmosphere of HR 8799e

Author

Frank Eisenhauer, Th. Henning, P. Mollière, Jingxiu Wang, E. F. van Dishoeck, T. Molyarova, Jinyi Shangguan, Pierre Kervella, Tomas Stolker, Alexandra Z. Greenbaum, Mathias Nowak, Sylvestre Lacour, Alice Zurlo, E. Nasedkin, Gabriel-Dominique Marleau, Gilles Otten, D. Semenov, Anne-Lise Maire, Ignas Snellen, Laurent Pueyo, Sasha Hinkley, Arthur Vigan, Laura Kreidberg, Benjamin Charnay, Paulo J. V. Garcia, Julien Girard, P. T. de Zeeuw, R. Garcia Lopez, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), 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 Paris Cité (UPCité), Max Planck Institute for Extraterrestrial Physics (MPE), Max-Planck-Gesellschaft, European Southern Observatory (ESO), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), 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), and Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES)

Subjects
010504 meteorology & atmospheric sciences, Opacity, FOS: Physical sciences, Context (language use), Astrophysics, 01 natural sciences, Spectral line, methods: numerical, Atmosphere, Planet, 0103 physical sciences, Radiative transfer, 010303 astronomy & astrophysics, instrumentation: spectrographs, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), planets and satellites: atmospheres, Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Scattering, Astronomy and Astrophysics, Exoplanet, radiative transfer, [SDU]Sciences of the Universe [physics], 13. Climate action, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

Clouds are ubiquitous in exoplanet atmospheres and represent a challenge for the model interpretation of their spectra. Complex cloud models are too numerically costly for generating a large number of spectra, while more efficient models may be too strongly simplified. We aim to constrain the atmospheric properties of the directly imaged planet HR 8799e with a free retrieval approach. We use our radiative transfer code petitRADTRANS for generating spectra, which we couple to the PyMultiNest tool. We added the effect of multiple scattering which is important for treating clouds. Two cloud model parameterizations are tested: the first incorporates the mixing and settling of condensates, the second simply parameterizes the functional form of the opacity. In mock retrievals, using an inadequate cloud model may result in atmospheres that are more isothermal and less cloudy than the input. Applying our framework on observations of HR 8799e made with the GPI, SPHERE and GRAVITY, we find a cloudy atmosphere governed by disequilibrium chemistry, confirming previous analyses. We retrieve that ${\rm C/O}=0.60_{-0.08}^{+0.07}$. Other models have not yet produced a well constrained C/O value for this planet. The retrieved C/O values of both cloud models are consistent, while leading to different atmospheric structures: cloudy, or more isothermal and less cloudy. Fitting the observations with the self-consistent Exo-REM model leads to comparable results, while not constraining C/O. With data from the most sensitive instruments, retrieval analyses of directly imaged planets are possible. The inferred C/O ratio of HR 8799e is independent of the cloud model and thus appears to be a robust. This C/O is consistent with stellar, which could indicate that the HR 8799e formed outside the CO$_2$ or CO iceline. As it is the innermost planet of the system, this constraint could apply to all HR 8799 planets., Comment: Accepted for publication in A&A, 28 pages, 13 figures, updated author list

Published
2020
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22. Rivaroxaban or aspirin for patent foramen ovale and embolic stroke of undetermined source: a prespecified subgroup analysis from the NAVIGATE ESUS trial

Author

Scott E Kasner, Balakumar Swaminathan, Pablo Lavados, Mukul Sharma, Keith Muir, Roland Veltkamp, Sebastian F Ameriso, Matthias Endres, Helmi Lutsep, Steven R Messé, J David Spence, Krassen Nedeltechev, Kanjana Perera, Gustavo Santo, Veronica Olavarria, Arne Lindgren, Shrikant Bangdiwala, Ashkan Shoamanesh, Scott D Berkowitz, Hardi Mundl, Stuart J Connolly, Robert G Hart, N Abdelhamid, D Abdul Rahman, M Abdul-Saheb, P Abreu, M Abroskina, F Abu Ahmad, S Accassat, M Acciaresi, A Adami, N Ahmad, F Ahmed, M Alberto Hawkes, F Alemseged, A Ali, R Altavilla, L Alwis, P Amarenco, S Amaro, LE Amaya Sanchez, A Amelia Pinto, SF Ameriso, H Amin, T Amino, AK Amjad, E Anagnostou, G Andersen, C Anderson, DC Anderson, M Andrea Falco, F Andres Mackinnon, D Andreu, M Androulakis, M Angel Gamero, G Angel Saredo, R Angeles Diaz, M Angels Font, S Anticoli, A Arauz, AA Arauz Gongora, P Araya, JF Arenillas Lara, S Arias Rivas, M Arnold, S Augustin, W Avelar, E Azevedo, V Babikian, A Bacellar, K Badalyan, HJ Bae, EM Baez Martinez, H Bagelmann, P Bailey, Z Bak, M Baker, A Balazs, D Baldaranov, I Balogun, T Balueva, Z Bankuti, M Bar, A Baranowska, J Bardutzky, S Barker Trejo, J Barlinn, F Baronnet, C Barroso, M Barteys, T Bartolottiova, A Barulin, M Bas, S Bashir, V Basile, R Bathe-Peters, R Bathula, C Batista, H Batur Caglayan, P Baumgartner, R Bazan, O Bazhenova, M Beaudry, J Beer, Y Behnam, C Beilei, A Beinlich, Y Bejot, A Belkin, OR Benavente, A Benjamin, V Berardi, D Bereczki, SD Berkowitz, J Berlingieri, W Berrios, J Berrouschot, M Bhandari, M Bhargavah, H Bicker, T Bicsak, M Bilik, D Bindila, J Birchenall, L Birnbaum, T Black, D Blacker, D Blacquiere, C Blanc-Labarre, C Blank, B Blazejewska-Hyzorek, S Bloch, E Bodiguel, E Bogdanov, L Boos, L Borcsik, N Bornstein, S Bouly, G Braga, I Bragado, MC Bravi, C Brokalaki, W Brola, R Brouns, D Bruce, J Brzoska-Mizgalska, B Buck, M Buksinska-Lisik, J Burke, M Burn, G Bustamante, L Cabrejo, K Cai, S Cajaraville, M Calejo, D Calvet, J Campillo, E Campos Costa, P Camps, H Can Alaydin, E Candeloro, C Canepa, CG Cantu Brito, M Cappellari, C Carcel, P Cardona Portela, F Cardoso, M Carek, M Carletti, J Carlos Portilla, P Caruso, I Casado-Naranjo, P Castellini, D Castro, F Castro Meira, A Cavallini, N Cayuela Caudevilla, S Cenciarelli, C Cereda, P Cerrone, A Chakrabarti, P Chaloulos-Iakovidis, A Chamorro, D Chandrasena, DI Chang, C Che, J Chembala, J Chen, Z Chen, T Chen, H Chen, X Chen, G Chen, L Chen, S Chen, B Cheripelli, M Chin, E Chiquete Anaya, M Chorazy, H Christensen, T Christensen, L Christian, F Chu, CS Chung, W Clark, R Clarke, S Claverie, E Clemente Agostoni, B Clissold, J Coelho, D Cohen, S Colakoglu, D Collas, R Condurso, SJ Connolly, D Consoli, C Constantin, AB Constantino Silva, L Contardo, A Corlobe, M Correia, C Correia, E Cortijo Garcia, B Coull, S Coutts, S Coveney, P Cras, R Crols, S Crozier, A Csanyi, L Csiba, K Csontos, R Csuha, L Cui, L Cunha, S Curtze, M Czerska, A Czlonkowska, M Czurko, M Czuryszkiewicz, M Dagnino, C Dai, A Daineko, G Dalek, D Damgaard, A Danese, K Dani, V Danku, W Dario Toledo, A Dávalos, A De Havenon, J De Keyser, N De Klippel, J De La Torre, A De Pauw, A De Smedt, R De Torres, MM De Vries Basson, J Dearborn, R Deganutto, M Degeorgia, I Deguchi, A Del Giudice, C Delcourt, R Delgado-Mederos, G Della Marca, B Delpont, S Deltour, DL Demets, M Dennis, J Desai, J Devine, I Dhollander, MT Di Mascio, M Diaconu, F Diaz Otero, J Dietzel, E Diez-Tejedor, N Ding, J Ding, M Diomedi, P Dioszeghy, M Distefano, V Domigo, E Dorodnicov, D Dossi, F Doubal, I Druzenko, P Du, J Du, T Duman, Y Duodu, D Dutta, L Dylewicz, J Eckstein, E Ehrensperger, S Ehrlich, G Einer Allende, B Elena Halac, S Elyas, M Endres, JM Engelbrecht, S Engelter, M Epinat, F Eren, M Esbjornsson, B Escribano, I Escudero, B Esisi, B Essa, M Esterbauer, N Evans, D Eveson, S Fabio, L Fang, S Fanta, M Fares, M Fatar, K Faust, A Favate, F Fazekas, M Federica Denaro, A Fedin, P Felipe Amaya, J Feng, K Ferencova, M Fernanda Gilli, MD Fernandez, PN Fernandez Pirrone, J Fernandez Vera, J Ferrari, A Ferreira, G Ferreira Junior, M Fidler, D Field, T Field, C Figueroa, J Fiksa, A Filipov, A Firstenfeld, L Fisch, U Fischer, M Fisselier, U Fiszer, F Fluri, G Fortea, K Fotherby, A Fraczek, E France, G Freitas, S Frey, M Frick, A Friedman, M Friedrich, G Frisullo, W Fryze, B Fuentes Gimeno, H Fujigasaki, K Fukuyama, A Furlan, G Furlanis, J Furnace, M Gabriel, E Gabriel Reich, RJ Gagliardi, F Galati, E Galli Giqueauk, A Gallina, E Gallinella, J Gallo, S Gangadharan, Y Gao, R Garcia Lopez, A Garcia Pastor, SM Garcia Sanchez, M Garnauf, P Garnier, D Gasecki, K Gasic, K Gasiorek, S Gasser, M Gaugg, M Gebreyohanns, K Gebura, J Geng, M Geniz Clavijo, K Georg Haeusler, R Geran, M Geremek, Z Gerocs, D Ghia, D Giannandrea, F Giatsidis, JA Gien Lopez, A Gil Nunez, L Gimenez, E Giralt, A Glabinski, D Gladstone, M Gliem, M Gluszkiewicz, R Goddeau, E Gogoleva, M Gokce, D Goldemund, K Golikov, A Gomes Neto, M Gomez Schneider, M Gomez-Choco, M Gomis, JF Gongora-Rivera, Y Gonysheva, L Gonzalez, ME Gonzalez Toledo, M Gottschal, I Gozdzik, S Grabowski, S Graf, D Green, D Greer, T Gregorio, S Greisenegger, I Greshnova, M Griebe, M Grzesik, J Guan, S Guarda, A Gueguen, C Guidoux, P Guillermo Povedano, B Guillon, V Guiraudg, G Gunathilagan, N Guryanova, V Gusev, G Gustavo Persi, R Gutiérrez, P Guyler, N Gyuker, V Hachinski, A Hajas, H Hallevi, G Hankey, GJ Hankey, L Hanouskova, L Hao, K Haraguchi, Y Haralur Sreekantaiah, S Haratz, D Hargroves, K Harkness, P Harmel, M Harrasser, RG Hart, M Harvey, R Hasan, Y Hasegawa, A Hassan, M Hattori, A Hatzitolios, M Hauk, T Hayashi, H Hayhoe, VS Hedna, M Heine, V Held, S Hellwig, J Henkner, N Henninger, S Hermans, J Hernandez, D Herrero, M Hervieu-Begue, R Herzig, L Hicken, M Hieber, M Hill, M Hirose, MC Hobeanu, B Hobson, M Hochstetter, J Hoe Heo, M Hoffmann, C Holmstedt, P Hon, KS Hong, Y Honma, A Horev, G Horgan, L Horvath, M Horvath, C Hoyer, D Huang, H Huang, B Huber, J Huhtakangas, M Hussain, S Igarashi, AM Iglesias Mohedano, J Ignacio Tembl, M Impellizzeri, Y Inanc, P Ioli, A Irina Aniculaesei, K Ishida, R Itabashi, H Iversen, A Jagolino, K Jakab, S Jander, H Janka, J Jankovych, J Jansen, L Jasek, M Javier Alet, L Javor, X Jin, P Jing, B Joachim, M Joan Macleod, M Johnson, J Jose Martin, C Joyner, K Judit Szabo, A Jun-Oconnell, R Jura, B Kaczorowska, J Kadlcikova, T Kahles, N Kakaletsis, I Kakuk, K Kalinowska, K Kaminska, C Kaneko, I Kanellos, P Kapeller, K Kapica-Topczewska, O Karasz, M Karlinski, JE Karlsson, K Kasa, E Kashaeva, SE Kasner, M Kaste, J Kasza, A Katalin Iljicsov, M Katsurayama, S Kaur, M Kawanishi, S Kaygorodtseva, K Ke, A Kei, J Keilitz, J Kellner, P Kelly, S Kelly, D Kemlink, M Kerekgyarto, I Keskinarkaus, D Khairutdinova, A Khanna, A Khaw, M Kholopov, C Khoumri, S Kirpicheva, H Kirshner, K Kitagawa, S Kittner, R Kivioja, F Klein, D Kleindorfer, T Kleinig, P Klivenyi, S Knecht, Y Kobayashi, A Kobayashi, M Koch, L Koehler, M Koivu, V Kolianov, I Koltsov, T Kondo, I Konkov, S Kopecky, E Korompoki, J Korpela, K Kosarz-Lanczek, A Koutroubi, K Kovacs, T Kovacs, H Kovacs, K Kowalczyk, M Kowalska, D Krajickova, M Kral, C Krarup Hansen, J Kraska, S Krebs, V Krejci, C Kremer, R Kreuzpointer, M Krzyzanowska, D Kucken, A Kulakowska, J Kunzmann, N Kurenkova, A Kuris, I Kurkowska-Jastrzebska, N Kurtenkova, O Kurushina, G Kusnick, M Kustova, T Kuwashiro, J Kwan Cha, A Lago, M Lagutenko, B Lajos, J Lambeck, C Lamy, A Landolfi, S Lanfranconi, W Lang, LB Lara Lezama, B Lara Rodriguez, T Largo, A Lasek-Bal, L Latte, V Lauer, P Lavados, R Le Bouc, R Leal Cantu, H Lechner, K Lecouturier, S Leder, J Lee, BC Lee, A Leger, E Leira, I Leisse, R Leker, G Lembo, L Lenskaya, J Leyden, G Li, M Li, S Li, J Li, G Liamis, H Liang, Z Liang, N Ligot, H Lin, R Lindert, A Lindgren, M Linna, T Litwin, K Liu, X Liu, L Llull, B Lohninger, M Longoni, C Loomis, D Lopes, M Lopez Fernandez, N Lopez Garza, A Lord, S Louw, R Lovasz, T Lowenkopf, Z Lu, SC Lubke-Detring, R Luder, S Lujan, B Luo, L Lupinogina, G Luschin, H Lutsep, A Lvova, J Ly, G.M. Grosse, H Ma, C Ma, M Machado, C Machado, S Macher, J Machetanz, F Macian-Montoro, E Mackey, A Mackey, G Maclean, J Maestre-Moreno, A Magadan, T Magyar, A Mahagney, A Majid, A Majjhoo, K Makaritsis, J Mandzia, M Mangas Guijarro, D Mangion, E Manios, S Mann, L Manning, C Manno, J Manuel Garcia, V Maqueda, M Mar Castellanos, M Mar Freijo, C Marando, S Marcela Lepera, J Marcos Couto, G Maria Bruera, L Maria Greco, A Maria Lorenzo, S Maria Obmann, A Maria Roa, C Marini, I Marinkovic, G Mario Sumay, C Mario Torres, M Marko, S Markova, H Markus, R Marsh, E Marsili, M Marta Esnaola, J Marta Moreno, J Marti-Fabregas, S Martina Angelocola, P Martínez Sánchez, N Martinez-Majander, S Martins, O Marzelik, S Mastrocola, G Matamala, A Matoltsy, B Matosevic, S Matsumoto, A Maud, G Mauri Cabdevila, Z May, Y Mayasi, A Mayr, T Mazzoli, K Mcarthur, L Mccullough, CE Medina Pech, F Medlin, M Mehdiratta, S Mehta, D Mehta, B Mehta, M Melis, E Melnikova, B Mendez, T Mendonca, JJ Mengual Chirifie, N Menon, A Mensch, E Meseguer, S Messe, K Metcalf, N Meyer, F Michas, N Micheletti, R Mikulik, H Milionis, B Miller, T Milling, C Minelli, J Minhas, M Minns, D Mircea, S Mishra, A Mismas, A Mistri, N Mitrovic, H Miyake, B Modrau, A Moey, C Molina, J Molina, A Molis, J Moller, S Molnar, F Moniche, C Monosi, V Monzani, M Moonis, R Morais, L Morales, A Morales, D Morar-Precup, F Moreton, C Moro, E Morozova, M Morton, T Morvan, E Morvan, T Motko, A Mowla, E Mozhejko, G Muddegowda, O Mudhar, T Mueller, C Muhl, KW Muir, H Mundl, S Munoz, C Murphy, S Murphy, A Murtuzova, T Musuka, J Mutzenbach, M Myint, W Mysliwy, M Naccarato, G Naeije, Y Nagakane, I Natarajan, D Navaratnam, A Nave, B Nazliel, K Nedeltchev, J Nel, H Nell, R Nemeth, L Nemeth, O Neto, K Ng, J Ngeh, L Nicolas Chialvo, T Nieminen, M Nikkanen, J Nikl, M Nikoforova, S Nishino, Y Nishiyama, X Njovane, S Nogawa, F Nombela, B Norrving, K Nosek, B Nowak, E Nowakowska-Sledz, G Ntaios, H Numminen, F Nunez, M Obadia, S Oberndorfer, A Obrezan, J Ochiai, W Oczkowski, MJ O'Donnell, A Odyniec, K Oh, M Ohira, Y Okamoto, M Okpala, S Okubo, L Olah, V Olavarria, J Oleszek, N Onat Demirci, V Ondar, G Ongun, K Ooyama, V Orosz, R Ortiz, G Osseby, E Österlund-Tauriala, C Ovesen, S Ozcekic Demirhan, J Ozdoba-Rot, S Ozturk, E Ozyurt, M Pablo Grecco, G Pablo Povedano, M Paciaroni, C Padiglioni, J Pagola, W Palasik, G Panczel, L Panos, G Papadopoulos, E Papadopoulou, A Papagiannis, V Papavasileiou, M Papina, JR Pardo De Donlebun, V Parisi, JM Park, J Pasten, N Patel, O Pavlik, M Pawelczyk, WF Peacock, H Pei, T Peisker, LF Pena Sedna, A Penn, S Pentek, E Pepper, L Pereira, K Perera, Y Perez, S Perez, P Perez Leguizamon, M Pernicka, R Perry, A Persico, Y Pesant, S Peska, D Peters, G Peters, L Pettigrew, T Phan, S Philippi, T Phinney, F Pico, A Pidal, B Piechowski-Jozwiak, A Pieroni, S Pineiro, V Piras, N Pizova, J Polanco, M Polin, A Polyakov, E Polychronopoulou, A Polymeris, D Popov, A Poppe, P Postorino, C Pozzerese, M Pradhan, L Prats, E Prazdnichkova, B Prendl, M Pretorius, P Profice, S Prokopenko, E Pudov, V Pujol Lereis, G Punzo Bravo, F Purroy, J Qiu, X Qu, V Quenardelle, H Quesada Garcia, L Radrizzani, A Radtke, T Raffelsberger, JM Ramirez Moreno, C Ramos-Estebanez, A Rani, P Rapantova, K Rashed, A Rasheed Nihara, J Rasmussen, L Redondo Robles, M Reif, P Reiner, P Rekova, A Renu, M Repetto, P Reyes, S Reyes Morales, JH Rha, J Ribeiro, S Ricci, C Richard, R Rigual, C Rinaldi, C Riveira Rodriguez, B Rizzato, TG Robinson, A Rocco, M Rodrigues, G Rodriguez, A Rodriguez Campello, F Rodriguez Lucci, M Rodriguez Yanez, C Roesler, C Roffe, R Roine, S Roine, A Roldan, F Romana Pezzella, M Romano, JS Roos, C Rosso, C Rostrup Kruuse, Y Roth, R Roukens, L Roveri, D Rozanski, J Rozniecki, C Rozsa, S Rudilosso, G Ruiz Ares, A Ruiz Franco, G Rum, J Ruuskanen, I Rybinnik, K Ryota, J Saarinen, V Saavedra, C Sabben, A Sabet, D Sagris, J Sahlas, N Sakai, P Salamanca, P Salgado, S Salig, T Salletmayr, M Salnikov, O Samoshkina, Y Samson, D Sanak, M Sànchez Cerón, P Santalucia, M Santamaria Cadavid, P Santiago, G Santo, B Sanz Cuesta, J Sargento, A Sarraj, K Sas, A Sas, O Satoshi, S Satsoglou, N Sattar, S Savitz, C Savopoulos, J Saw, M Sawicka, R Sawyer, T Scandura, N Schillinger, J Schindler, F Schlachetzki, I Schneider, R Schuppner, J Schurig, CJ Schwarzbach, M Sebejova, G Seidel, L Sekaran, D Selcuk, J Selvarajah, A Semerano, J Semjen, D Semushina, S Sen, M Seok Park, J Serena, O Serhat Tokgoz, W Serles, F Serrano, M Sevin, L Seynaeve, S Shah, N Shamalov, T Shang, M Sharma, A Sharrief, M Shazam Hussain, I Shchukin, W Shen, E Shepeleva, I Shinsuke, A Shmonin, A Shoamanesh, A Shuaib, A Shulga, G Sibolt, I Sibon, I Sicilia, M Siebert, E Sieczkowska, C Sila, AA Silva, D Silva, P Silva, Y Silva, M Silvestrini, Z Simony, A Simpkins, B Singh, D Sinha, I Sipos, O Skoda, P Skowron, M Skowronska, B Sliwinska, J Slonkova, A Smolkin, A Smyth, P Sobolewski, A Sobota, SI Sohn, M Soldatov, I Solganov, L Soloveva, E Solovyeva, N Sonntag, P Soors, M Sorgun, C Soriano, D Spence, K Spengos, L Sposato, G Staaf, K Stadler, L Stakhovskaya, K Stamatelopoulos, S Steinert, I Stetkarova, M Stiehm, R Stocker, J Stoinski, A Stoll, G Stotts, A Stumpp, P Sucapane, T Suenaga, X Sun, S Sundararajan, J Sung Kim, H Suzuki, N Svaneborg, G Szasz, W Szczuchniak, S Szczyrba, N Szegedi, A Szekely, Z Szewczyk, G Szilagyi, S Szlufik, K Szoboszlai, L Szpisjak, R Sztajzel, L Sztriha, SE Ta Wil, J Taggeselle, K Takamatsu, M Takao, W Taki, S Takizawa, M Talahma, A Tamayo, J Tan, D Tanne, A Tapanainen, T Tapiola, J Tarasiuk, T Tatlisumak, A Tayal, S Tcvetkova, P Teal, J Tejada Garcia, H Tejada Meza, D Tenora, M Terceno, A Terentiou, S Tezcan, D Thaler, A Thomson, E Thouvenot, M Tiainen, I Timberg, S Timsit, A Tinchon, D Tirschwell, C Togay Isikay, K Tokunaga, M Tolino, C Toloza, G Tomelleri, K Tomoyuki, LM Tomppo, Z Tong, L Tong, D Toni, J Torres, C Tossavainen, G Toth, A Tountopoulou, E Touze, M Tovar, K Toyoda, S Trillo, A Trommer, D Tropepi, D Tryambake, H Tu, S Tuetuencue, R Tumova, O Tumpula, G Turc, A Tutaj, J Tynkkynen, S Uchiyama, U Uchwat, L Uhrinyakova, R Ulku Acar, D Uluduz Ugurlu, X Urra, S Urui, M Usero Ruiz, D Vaclavik, K Vahedi, A Valikovics, J Valpas, P Van Acker, W Van Daele, G Vanderschueren, L Vanina Jure, R Varela, Z Varga, J Varvat, N Varvyanskaya, A Vasco Salgado, P Vasko, L Vass, S Vassilopoulou, I Vastagh, P Vazquez, L Vecsei, R Veltkamp, M Venti, M Verdugo, V Verocai, M Veronica Marroquin, C Veronica Simonsini, T Veverka, M Vigl, A Vila, C Vilar, JA Villanueva Osorio, J Virta, E Vitkova, B Voglsperger, J Volna, PA Von Weitzel-Mudersbach, N Vora, I Voznyuk, A Wach-Klink, A Wacongne, D Walters, Y Wang, J Wang, L Wang, X Wang, W Wang, N Wang, D Wang, H Wang, W Warnack, K Wartenberg, R Waters, M Waters, T Webb, J Weber, G Weiss, K Weissenborn, JI Weitz, B Weller, G Wen, G Weng, P Werner, D Werring, P Wester, W Whiteley, R Whiting, T Wijeratne, C Willems, L Wilson, C Wilson, T Winder, J Windt, A Winkler, A Winska-Tereszkiewicz, A Wisniewska, M Wittayer, A Wlodek, A Wojnarowska-Arendt, M Wolf, V Wolff, C Wolter, A Wong, H Wook Nah, H Worthmann, W Wu, S Wu, S Wunderlich, H Wurzinger, DG Wyse, B Xiao, W Xiaopeng, A Ximenez-Carrillo, L Xiong, Y Xiong, W Xiong, Y Xu, J Xu, Z Xu, B Yalo, T Yamada, M Yamasaki, L Yang, Y Yang, X Yang, Q Yang, B Yang, J Yang, I Yasuhiro, M Yee Lam, C Yegappan, S Yip, E Ylikallio, P Ylikotila, A Yongwon Jin, BW Yoon, Y Yoshida, L Yperzeele, H Yuan, H Yuasa, J Zalewska, C Zanferrari, E Zapata, D Zboznovits, I Zelenka, C Zhang, B Zhang, S Zhang, M Zhang, X Zhang, J Zhang, L Zhao, O Zhirnova, L Zhou, J Zielinska-Turek, I Zinchenko, M Ziomek, A Zitzmann, R Zweifler, J Zwiernik, Yperzeele, Laetitia, and NAVIGATE ESUS Investigators

Subjects
Male, International Cooperation, 030204 cardiovascular system & hematology, antiplatelet therapy, law.invention, Neurology (clinical), ischemic stroke, anticoagulation, Cohort Studies, 0302 clinical medicine, Randomized controlled trial, Rivaroxaban, law, Stroke, education.field_of_study, Aspirin, Anticoagulant, Settore BIO/14, Middle Aged, 3. Good health, Treatment Outcome, N/A, Cardiology, Platelet aggregation inhibitor, Settore MED/26 - Neurologia, Female, medicine.drug, medicine.medical_specialty, medicine.drug_class, MEDLINE, Population, Foramen Ovale, Patent, Subgroup analysis, Article, Statistics, Nonparametric, 03 medical and health sciences, Double-Blind Method, Internal medicine, medicine, Humans, education, Aged, business.industry, medicine.disease, Human medicine, business, 030217 neurology & neurosurgery, Platelet Aggregation Inhibitors, Factor Xa Inhibitors
Abstract

Background: \ud Patent foramen ovale (PFO) is a contributor to embolic stroke of undetermined source (ESUS). Subgroup analyses from previous studies suggest that anticoagulation could reduce recurrent stroke compared with antiplatelet therapy. We hypothesised that anticoagulant treatment with rivaroxaban, an oral factor Xa inhibitor, would reduce the risk of recurrent ischaemic stroke compared with aspirin among patients with PFO enrolled in the NAVIGATE ESUS trial.\ud \ud Methods: \ud NAVIGATE ESUS was a double-blinded, randomised, phase 3 trial done at 459 centres in 31 countries that assessed the efficacy and safety of rivaroxaban versus aspirin for secondary stroke prevention in patients with ESUS. For this prespecified subgroup analysis, cohorts with and without PFO were defined on the basis of transthoracic echocardiography (TTE) and transoesophageal echocardiography (TOE). The primary efficacy outcome was time to recurrent ischaemic stroke between treatment groups. The primary safety outcome was major bleeding, according to the criteria of the International Society of Thrombosis and Haemostasis. The primary analyses were based on the intention-to-treat population. Additionally, we did a systematic review and random-effects meta-analysis of studies in which patients with cryptogenic stroke and PFO were randomly assigned to receive anticoagulant or antiplatelet therapy.\ud \ud Findings: \ud Between Dec 23, 2014, and Sept 20, 2017, 7213 participants were enrolled and assigned to receive rivaroxaban (n=3609) or aspirin (n=3604). Patients were followed up for a mean of 11 months because of early trial termination. PFO was reported as present in 534 (7·4%) patients on the basis of either TTE or TOE. Patients with PFO assigned to receive aspirin had a recurrent ischaemic stroke rate of 4·8 events per 100 person-years compared with 2·6 events per 100 person-years in those treated with rivaroxaban. Among patients with known PFO, there was insufficient evidence to support a difference in risk of recurrent ischaemic stroke between rivaroxaban and aspirin (hazard ratio [HR] 0·54; 95% CI 0·22–1·36), and the risk was similar for those without known PFO (1·06; 0·84–1·33; pinteraction=0·18). The risks of major bleeding with rivaroxaban versus aspirin were similar in patients with PFO detected (HR 2·05; 95% CI 0·51–8·18) and in those without PFO detected (HR 2·82; 95% CI 1·69–4·70; pinteraction=0·68). The random-effects meta-analysis combined data from NAVIGATE ESUS with data from two previous trials (PICSS and CLOSE) and yielded a summary odds ratio of 0·48 (95% CI 0·24–0·96; p=0·04) for ischaemic stroke in favour of anticoagulation, without evidence of heterogeneity.\ud \ud Interpretation: \ud Among patients with ESUS who have PFO, anticoagulation might reduce the risk of recurrent stroke by about half, although substantial imprecision remains. Dedicated trials of anticoagulation versus antiplatelet therapy or PFO closure, or both, are warranted.\ud \ud Funding: \ud Bayer and Janssen.

Published
2018
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23. Parsec-scale jets driven by high-mass young stellar objects. Connecting the au- and the parsec-scale jet in IRAS 13481-6124

Author

B. Stecklum, Gerd Weigelt, Stefan Kraus, R. Fedriani, R. Garcia Lopez, Deirdre Coffey, A. Caratti o Garatti, Tom Ray, and C. M. Walmsley

Subjects
IRAS 13481-6124, Young stellar object, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Spectroscopic, 01 natural sciences, 7. Clean energy, Interstellar medium, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Emission spectrum, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Physics, Very Large Telescope, Jet (fluid), 010308 nuclear & particles physics, Star formation, Astronomy and Astrophysics, Position angle, Stars, Astrophysics - Astrophysics of Galaxies, Accretion (astrophysics), Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Astrophysics::Earth and Planetary Astrophysics
Abstract

Context: Protostellar jets in high-mass young stellar objects (HMYSOs) play a key role in the understanding of star formation and provide us with an excellent tool to study fundamental properties of HMYSOs. Aims: We aim at studying the physical and kinematic properties of the near-IR (NIR) jet of IRAS\,13481-6124 from au to parsec scales. Methods: Our study includes NIR data from the Very Large Telescope instruments SINFONI, CRIRES, and ISAAC. Information about the source and its immediate environment is retrieved with SINFONI. The technique of spectro-astrometry is performed with CRIRES to study the jet on au scales. The parsec-scale jet and its kinematic and dynamic properties are investigated using ISAAC. Results: The SINFONI spectra in the $H$ and $K$ band are rich in emission lines that are mainly associated with ejection and accretion processes. Spectro-astrometry is applied to the Br$\gamma$ line, and for the first time, to the Br$\alpha$ line, revealing their jet origin with milliarcsecond-scale photocentre displacements ($11-15$\,au). This allows us to constrain the kinematics of the au-scale jet and to derive its position angle ($\sim216^{\circ}$). ISAAC spectroscopy reveals H$_2$ emission along the parsec-scale jet, which allows us to infer kinematic and dynamic properties of the NIR parsec-scale jet. The mass-loss rate inferred for the NIR jet is $\dot{M}_\mathrm{ejec}\sim10^{-4}\mathrm{\,M_\odot\,yr^{-1}}$ and the thrust is $\dot{P}\sim10^{-2}\mathrm{\,M_\odot\,yr^{-1}\,km\,s^{-1}}$ , which is roughly constant for the formation history of the young star. A tentative estimate of the ionisation fraction is derived for the massive jet by comparing the radio and NIR mass-loss rates. An ionisation fraction $\lesssim8\%$ is obtained, which means that the bulk of the ejecta is traced by the NIR jet and that the radio jet only delineates a small portion of it., Comment: Accepted for publication in A&A

Published
2018
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24. Detection of the gravitational redshift in the orbit of the star S2 near the Galactic centre massive black hole

Author

R.-R. Rohloff, Andreas Eckart, Sarah Kendrew, Maryam Habibi, Joany Andreina Manjarres Ramos, S. Kellner, Nicolas Blind, D. Ziegler, Wolfgang Brandner, Casey Deen, Bernard Lazareff, Jean-Philippe Berger, Gérard Zins, M. Haug, A. Ramirez, Eric Gendron, F. Haußmann, Thomas Ott, E. Müler, Silvia Scheithauer, Jason Spyromilio, Andreas Kaufer, Xavier Haubois, Markus Schöller, Eckhard Sturm, C. Collin, Stefan Hippler, Laurent Jocou, Myriam Benisty, Julien Woillez, Linda J. Tacconi, A. Buron, Imke Wank, S. von Fellenberg, M. Wiest, Paulo Gordo, Luca Pasquini, Pierre Kervella, L. Palanca, Magdalena Lippa, Martin Kulas, Roderick Dembet, Gilles Duvert, Z. Hubert, Jason Dexter, Yann Clénet, P. T. de Zeeuw, C. Rau, A. Jimenez Rosales, H. Bonnet, Sylvestre Lacour, Guy Perrin, Odele Straub, P. Fédou, J.-B. Le Bouquin, Christian Straubmeier, S. Yazici, Ekkehard Wieprecht, Gérard Rousset, V. Lapeyrère, N. M. Förster Schreiber, Sebastian Rabien, Felix Widmann, Th. Henning, F. Delplancke-Ströbele, M. Bauböck, F. Chapron, Frank Eisenhauer, Gert Finger, R. Garcia Lopez, G. Rodríguez-Coira, Reinhard Genzel, Frederic H. Vincent, Pierre Léna, Thibaut Paumard, Narsireddy Anugu, Idel Waisberg, J. Sanchez-Bermudez, N. Schuler, Karine Perraut, P. M. Plewa, Paulo J. V. Garcia, António Amorim, Yitping Kok, Oliver Pfuhl, Lieselotte Jochum, V. dCoudé u Foresto, Matthew Horrobin, Udo Neumann, Rainer Lenzen, Erich Wiezorrek, Antoine Mérand, Konrad R. W. Tristram, Norbert Hubin, Feng Gao, Stefan Gillessen, Roberto Abuter, 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), GRAVITY, 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), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), and 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)

Subjects
General relativity, black hole physics, FOS: Physical sciences, Astrophysics, Physics - Classical Physics, General Relativity and Quantum Cosmology (gr-qc), Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, General Relativity and Quantum Cosmology, Gravitation, Gravitational field, 0103 physical sciences, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Physics, Very Large Telescope, Galaxy: center, 010308 nuclear & particles physics, Classical Physics (physics.class-ph), Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Galaxy, [PHYS.PHYS.PHYS-GEN-PH]Physics [physics]/Physics [physics]/General Physics [physics.gen-ph], Black hole, Space and Planetary Science, gravitation, Astrophysics of Galaxies (astro-ph.GA), [PHYS.GRQC]Physics [physics]/General Relativity and Quantum Cosmology [gr-qc], Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Schwarzschild radius, Gravitational redshift
Abstract

The highly elliptical, 16-year-period orbit of the star S2 around the massive black hole candidate Sgr A* is a sensitive probe of the gravitational field in the Galactic centre. Near pericentre at 120 AU, ~1400 Schwarzschild radii, the star has an orbital speed of ~7650 km/s, such that the first-order effects of Special and General Relativity have now become detectable with current capabilities. Over the past 26 years, we have monitored the radial velocity and motion on the sky of S2, mainly with the SINFONI and NACO adaptive optics instruments on the ESO Very Large Telescope, and since 2016 and leading up to the pericentre approach in May 2018, with the four-telescope interferometric beam-combiner instrument GRAVITY. From data up to and including pericentre, we robustly detect the combined gravitational redshift and relativistic transverse Doppler effect for S2 of z ~ 200 km/s / c with different statistical analysis methods. When parameterising the post-Newtonian contribution from these effects by a factor f, with f = 0 and f = 1 corresponding to the Newtonian and general relativistic limits, respectively, we find from posterior fitting with different weighting schemes f = 0.90 +/- 0.09 (stat) +\- 0.15 (sys). The S2 data are inconsistent with pure Newtonian dynamics., Comment: Accepted for publication in A&A Letters, 29 June 2018, 10 pages, 6 figures, corresponding author: F. Eisenhauer

Published
2018
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25. Successful Introduction of the First Worldwide 30 Casing while Drilling Job Saves 1.31 Days in an Exploratory Well in Shallow Waters, Mexico

Author

J.. Karimov, L. A. Zamudio Lopez, J. C. Perez Cabrera, F.. Olcese, J. R. Garcia Lopez, R.. Perez Ibarra, J. A. Carranza, Gustavo García Gómez, J.. Mafla, P.. Gil Rodriguez, O.. Luna Gonzalez, M.. Noguez, M.. Bavidge, M.. Sotelo Fonseca, M.. Gomez Tapia, Cesar Karrer, P.. Hurtado Cardenas, A.. Van Balen, and A.. Mora

Subjects
Engineering, Mining engineering, Petroleum engineering, business.industry, Drilling, business, Casing
Abstract

In exploration wells in shallow waters of Mexico, the challenge of reducing drilling time and enhancing efficiency of well construction had become a problem on a daily basis. The continued use and success of Casing while Drilling (CwD) led the operator and service companies to embark upon a more ambitious project. Using the learning curve of previous 20″ CwD conductor sections, the first 34″ PDC drillable drill bit was designed and the first Casing Running Tool (CRT) for 30″ casing was utilized. These tools were used to apply the technology in the conductor sections of wells targeting Mesozoic formations. A technical feasibility study was performed by the operator and service companies involved to analyze the viability of executing this whilst creating new products. This saw the implementation of CwD using 30″ casing, an integral drilling system using casing as the drill string and a PDC drillable bit that allows drilling and casing of the section to take place simultaneously and eliminates the need to assemble a 36″ drilling BHA and, subsequently run casing. Once the CwD BHA (Casing + Drillable drill bit) reaches the final depth of the section, the hole is already cased and ready to cement. This challenged the service companies' engineering departments to develop the custom made tools for the application. In the first well, the original plan was to drill the 30″ section using a 36″ roller cone bit, drilling from sea bed (+/-78m) to 250 mts. This was the candidate well that the operator chose to utilize an ″unconventional″ drilling system to ensure reaching TD in a single run prior to cementing the casing. The 30″ × 34″ conductor section was drilled and cased at a depth of 256 meters, drilling a total of 178 meters with the PDC drillable drill bit (4 blades + 19 mm cutters) in 9:52 hrs., with an average rate of penetration (ROP) of 18.04 m/hr., and then preparations for cementing the 30″casing began. This entire operation represented a 26.3% time reduction compared with a conventional drilling operation This document will show the methodology and technology used in Mexico Marine Exploratory fields to reduce and mitigate the risk of not setting the casing at TD, focusing on the pre-planning stage, proper bit selection, Torque & Drag (T&D) analysis, casing fatigue life analysis and the use of new technology with a high success ratio on the operations in order to add value and ensure the customer' satisfaction.

Published
2017
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26. Deep into the Water Fountains: The case of IRAS 18043-2116

Author

A. F. Pérez-Sánchez, Luis F. Rodríguez, Daniel Tafoya Martinez, R. Garcia Lopez, and Wouter Vlemmings

Subjects
Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 7. Clean energy, 01 natural sciences, law.invention, Telescope, Jansky, law, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Emission spectrum, Maser, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Physics, Very Large Telescope, Nebula, 010308 nuclear & particles physics, Near-infrared spectroscopy, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Stars, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Astrophysics::Earth and Planetary Astrophysics
Abstract

(Abridged) The formation of large-scale (hundreds to few thousands of AU) bipolar structures in the circumstellar envelopes (CSEs) of post-Asymptotic Giant Branch (post-AGB) stars is poorly understood. The shape of these structures, traced by emission from fast molecular outflows, suggests that the dynamics at the innermost regions of these CSEs does not depend only on the energy of the radiation field of the central star. Deep into the Water Fountains is an observational project based on the results of programs carried out with three telescope facilities: The Karl G. Jansky Very Large Array (JVLA), The Australia Telescope Compact Array (ATCA), and the Very Large Telescope (SINFONI-VLT). Here we report the results of the observations towards the WF nebula IRAS 18043$-$2116: Detection of radio continuum emission in the frequency range 1.5GHz - 8.0GHz; H$_{2}$O maser spectral features and radio continuum emission detected at 22GHz, and H$_{2}$ ro-vibrational emission lines detected at the near infrared. The high-velocity H$_{2}$O maser spectral features, and the shock-excited H$_{2}$ emission detected could be produced in molecular layers which are swept up as a consequence of the propagation of a jet-driven wind. Using the derived H$_{2}$ column density, we estimated a molecular mass-loss rate of the order of $10^{-9}$M$_{\odot}$yr$^{-1}$. On the other hand, if the radio continuum flux detected is generated as a consequence of the propagation of a thermal radio jet, the mass-loss rate associated to the outflowing ionized material is of the order of 10$^{-5}$M$_{\odot}$yr$^{-1}$. The presence of a rotating disk could be a plausible explanation for the mass-loss rates estimated., Comment: 10 pages, 5 figures. Accepted for publication in A&A

Published
2017
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27. Disk-mediated accretion burst in a high-mass young stellar object

Author

A. Caratti o Garatti, C. M. Walmsley, Luca Moscadelli, Riccardo Cesaroni, R. Garcia Lopez, B. Stecklum, Alberto Sanna, Tom Ray, Randolf Klein, Alfred Krabbe, W. J. de Wit, C. Fischer, Javier Ibáñez, J. Eislöffel, Rene D. Oudmaijer, and Jochen Greiner

Subjects
Stellar mass, Young stellar object, Astrophysics::High Energy Astrophysical Phenomena, General Physics and Astronomy, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Intermediate polar, 0103 physical sciences, Protostar, Astrophysics::Solar and Stellar Astrophysics, Emission spectrum, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Physics, Coalescence (physics), 010308 nuclear & particles physics, Star formation, Astronomy, Astrophysics - Astrophysics of Galaxies, Stars, Astrophysics - Solar and Stellar Astrophysics, Astrophysics of Galaxies (astro-ph.GA), Astrophysics::Earth and Planetary Astrophysics
Abstract

Solar-mass stars form via circumstellar disk accretion (disk-mediated accretion). Recent findings indicate that this process is likely episodic in the form of accretion bursts, possibly caused by disk fragmentation. Although it cannot be ruled out that high-mass young stellar objects (HMYSOs; $M>$8 M$_\odot$, $L_{bol}>$5$\times$10$^3$ L$_\odot$) arise from the coalescence of their low-mass brethren, latest results suggest that they more likely form via disks. Accordingly, disk-mediated accretion bursts should occur. Here we report on the discovery of the first disk-mediated accretion burst from a $\sim$20 M$_\odot$ HMYSO. Our near-infrared images show the brightening of the central source and its outflow cavities. Near-infrared spectroscopy reveals emission lines typical of accretion bursts in low-mass protostars, but orders of magnitude more luminous. Moreover, the energy released and the inferred mass-accretion rate are also orders of magnitude larger. Our results identify disk accretion as the common mechanism of star formation across the entire stellar mass spectrum., 27 pages, 3 figures. Published in Nature Physics, 2016, Vol. 13, pag. 276

Published
2017
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28. Submilliarcsecond Optical Interferometry of the High-mass X-Ray Binary BP Cru with VLTI/GRAVITY

Author

Christian Straubmeier, Th. Henning, Stefan Hippler, Gert Finger, Antoine Mérand, W. J. de Wit, H. Bonnet, Stefan Gillessen, R.-R. Rohloff, T. Ott, F. Haussmann, Eckhard Sturm, Laurent Jocou, Andreas Eckart, Yann Clénet, Martin Kulas, Oliver Pfuhl, Nicolas Blind, Jean-Philippe Berger, Pierre Léna, Jason Dexter, Senol Yazici, Markus Schöller, Julien Woillez, R. Genzel, Lieselotte Jochum, Sebastian Rabien, Gérard Rousset, Silvia Scheithauer, C. Rau, Z. Hubert, Frederic H. Vincent, Joany Andreina Manjarres Ramos, P. Fédou, V. Lapeyrère, Marcus Haug, Guy Perrin, Laurent Pallanca, Wolfgang Brandner, Ewald Müller, R. Garcia Lopez, Imke Wank, Roberto Abuter, F. Delplancke-Ströbele, Sylvestre Lacour, Karine Perraut, J.-B. Le Bouquin, Frank Eisenhauer, A. Buron, Idel Waisberg, Yitping Kok, Matthew Horrobin, Paulo J. V. Garcia, J. Sanchez-Bermudez, Erich Wiezorrek, Casey Deen, R. Dembet, Pierre Kervella, Magdalena Lippa, A. Ramirez, Ekkehard Wieprecht, Markus Wittkowski, Johana Panduro, Thibaut Paumard, Narsireddy Anugu, António Amorim, Eric Gendron, Xavier Haubois, M. Wiest, Gilles Duvert, 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), 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), GRAVITY, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), 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), 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 ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Observatoire de Paris-Université Paris Diderot - Paris 7 ( UPD7 ) -Centre National de la Recherche Scientifique ( CNRS ), Institut de Planétologie et d'Astrophysique de Grenoble ( IPAG ), Observatoire des Sciences de l'Univers de Grenoble ( OSUG ), and 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 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 ) -Centre National de la Recherche Scientifique ( CNRS )

Subjects
Physics, Final version, Gravity (chemistry), 010308 nuclear & particles physics, [ PHYS.ASTR ] Physics [physics]/Astrophysics [astro-ph], X-ray binary, techniques: high angular resolution, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, circumstellar matter, Interferometry, X-rays: binaries, 13. Climate action, Space and Planetary Science, techniques: interferometric, 0103 physical sciences, High mass, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, X-rays: individual
Abstract

International audience; We observe the high-mass X-ray binary (HMXB) BP Cru using interferometry in the near-infrared K band with VLTI/GRAVITY. Continuum visibilities are at most partially resolved, consistent with the predicted size of the hypergiant. Differential visibility amplitude (${\rm{\Delta }}| V| \sim 5 \% $) and phase (${\rm{\Delta }}\phi \sim 2^\circ $) signatures are observed across the He i $2.059\,\mu {\rm{m}}$ and Brγ lines, the latter seen strongly in emission, unusual for the donor star’s spectral type. For a baseline $B\sim 100$ m, the differential phase rms $\sim 0\buildrel{\circ}\over{.} 2$ corresponds to an astrometric precision of $\sim 2\,\mu \mathrm{as}$. We generalize expressions for image centroid displacements and variances in the marginally resolved limit of interferometry to spectrally resolved data, and use them to derive model-independent properties of the emission such as its asymmetry, extension, and strong wavelength dependence. We propose geometric models based on an extended and distorted wind and/or a high-density gas stream, which has long been predicted to be present in this system. The observations show that optical interferometry is now able to resolve HMXBs at the spatial scale where accretion takes place, and therefore to probe the effects of the gravitational and radiation fields of the compact object on its environment.

Published
2017
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29. Publisher Correction: Measuring the ionisation fraction in a jet from a massive protostar

Author

Melvin Hoare, Deirdre Coffey, A. Caratti o Garatti, S. J. D. Purser, Alberto Sanna, Tom Ray, R. Garcia-Lopez, Jonathan C. Tan, B. Stecklum, and R. Fedriani

Subjects
Physics, Jet (fluid), Multidisciplinary, Science, General Physics and Astronomy, Fraction (chemistry), General Chemistry, Astrophysics, General Biochemistry, Genetics and Molecular Biology, Ionization, Protostar, lcsh:Q, lcsh:Science
Abstract

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Published
2019

30. MAGIC Upper Limits on the Very High Energy Emission from Gamma‐Ray Bursts

Author

J. Albert, E. Aliu, H. Anderhub, P. Antoranz, A. Armada, C. Baixeras, J. A. Barrio, H. Bartko, D. Bastieri, J. Becker, W. Bednarek, K. Berger, C. Bigongiari, A. Biland, R. K. Bock, P. Bordas, V. Bosch‐Ramon, T. Bretz, I. Britvitch, M. Camara, E. Carmona, A. Chilingarian, S. Ciprini, J. A. Coarasa, S. Commichau, J. L. Contreras, J. Cortina, M. T. Costado, V. Curtef, V. Danielyan, F. Dazzi, A. De Angelis, C. Delgado, R. de los Reyes, B. De Lotto, E. Domingo‐Santamaria, D. Dorner, M. Doro, M. Errando, M. Fagiolini, D. Ferenc, E. Fernandez, R. Firpo, J. Flix, M. V. Fonseca, L. Font, M. Fuchs, N. Galante, R. Garcia‐Lopez, M. Garczarczyk, M. Gaug, M. Giller, F. Goebel, D. Hakobyan, M. Hayashida, T. Hengstebeck, A. Herrero, D. Hohne, J. Hose, C. C. Hsu, P. Jacon, T. Jogler, O. Kalekin, R. Kosyra, D. Kranich, R. Kritzer, A. Laille, T. Lenisa, P. Liebing, E. Lindfors, S. Lombardi, F. Longo, J. Lopez, M. Lopez, E. Lorenz, P. Majumdar, G. Maneva, K. Mannheim, O. Mansutti, M. Mariotti, M. Martinez, D. Mazin, C. Merck, M. Meucci, M. Meyer, J. M. Miranda, R. Mirzoyan, S. Mizobuchi, A. Moralejo, K. Nilsson, J. Ninkovic, E. Ona‐Wilhelmi, N. Otte, I. Oya, D. Paneque, M. Panniello, R. Paoletti, J. M. Paredes, M. Pasanen, D. Pascoli, F. Pauss, R. Pegna, M. Persic, L. Peruzzo, A. Piccioli, M. Poller, E. Prandini, N. Puchades, A. Raymers, W. Rhode, M. Ribo, J. Rico, M. Rissi, A. Robert, S. Rugamer, A. Saggion, A. Sanchez, P. Sartori, V. Scalzotto, V. Scapin, R. Schmitt, T. Schweizer, M. Shayduk, K. Shinozaki, S. N. Shore, N. Sidro, A. Sillanpaa, D. Sobczynska, A. Stamerra, L. S. Stark, L. Takalo, P. Temnikov, D. Tescaro, M. Teshima, N. Tonello, D. F. Torres, N. Turini, H. Vankov, V. Vitale, R. M. Wagner, T. Wibig, W. Wittek, R. Zanin, J. Zapatero, J., Albert, E., Aliu, H., Anderhub, P., Antoranz, A., Armada, C., Baixera, J. A., Barrio, H., Bartko, D., Bastieri, J., Becker, W., Bednarek, K., Berger, C., Bigongiari, A., Biland, R. K., Bock, P., Borda, V., Bosch Ramon, T., Bretz, I., Britvitch, M., Camara, E., Carmona, A., Chilingarian, S., Ciprini, J. A., Coarasa, S., Commichau, J. L., Contrera, J., Cortina, M. T., Costado, V., Curtef, V., Danielyan, F., Dazzi, A. D., Angeli, C., Delgado, R. d., los Reye, B. D., Lotto, E., Domingo Santamaria, D., Dorner, M., Doro, M., Errando, M., Fagiolini, D., Ferenc, E., Fernandez, R., Firpo, J., Flix, M. V., Fonseca, L., Font, M., Fuch, N., Galante, R., Garcia Lopez, M., Garczarczyk, M., Gaug, M., Giller, F., Goebel, D., Hakobyan, M., Hayashida, T., Hengstebeck, A., Herrero, D., Hohne, J., Hose, C. C., Hsu, P., Jacon, T., Jogler, O., Kalekin, R., Kosyra, D., Kranich, R., Kritzer, A., Laille, T., Lenisa, P., Liebing, E., Lindfor, S., Lombardi, Longo, Francesco, J., Lopez, M., Lopez, E., Lorenz, P., Majumdar, G., Maneva, K., Mannheim, O., Mansutti, M., Mariotti, M., Martinez, D., Mazin, C., Merck, M., Meucci, M., Meyer, J. M., Miranda, R., Mirzoyan, S., Mizobuchi, A., Moralejo, K., Nilsson, J., Ninkovic, E., Ona Wilhelmi, N., Otte, I., Oya, D., Paneque, M., Panniello, R., Paoletti, J. M., Parede, M., Pasanen, D., Pascoli, F., Pau, R., Pegna, M., Persic, L., Peruzzo, A., Piccioli, M., Poller, E., Prandini, N., Puchade, A., Raymer, W., Rhode, M., Ribo, J., Rico, M., Rissi, A., Robert, S., Rugamer, A., Saggion, A., Sanchez, P., Sartori, V., Scalzotto, V., Scapin, R., Schmitt, T., Schweizer, M., Shayduk, K., Shinozaki, S. N., Shore, N., Sidro, A., Sillanpaa, D., Sobczynska, A., Stamerra, L. S., Stark, L., Takalo, P., Temnikov, D., Tescaro, M., Teshima, N., Tonello, D. F., Torre, N., Turini, H., Vankov, V., Vitale, R. M., Wagner, T., Wibig, W., Wittek, R., Zanin, and J., Zapatero

Subjects
High energy, gamma ray astronomy, IMAGING CHERENKOV DETECTOR, Astrophysics::High Energy Astrophysical Phenomena, Very High Energy Gamma-ray Astronomy, Gamma-ray Bursts, MAGIC telescope, Extrapolation, FIREBALLS, Astrophysics, COMPTON EMISSION, Power law, GRB 050713A, Observacions astronòmiques, SEARCH, Gamma ray astronomy, Astronomia de raigs gamma, SPECTRA, MAGIC (telescope), LONG-DURATION, TEV EMISSION, AFTERGLOWS, SYNCHROTRON, COMPONENT, Zenith, Physics, Scattering, Attenuation, Astronomy and Astrophysics, Redshift, Space and Planetary Science, Gamma-ray Burst, Electrónica, Física nuclear, Electricidad, Astronomical observations
Abstract

During its first data cycle, between 2005 and the beginning of 2006, the fast repositioning system of the MAGIC telescope allowed the observation of nine different gamma-ray bursts as possible sources of very high energy gamma-rays. These observations were triggered by alerts from Swift, HETE-2, and INTEGRAL; they started as quickly as possible after the alerts and lasted for several minutes, with an energy threshold varying between 80 and 200 GeV, depending on the zenith angle of the burst. No evidence for gamma signals was found, and upper limits for the flux were derived for all events using the standard analysis chain of MAGIC. For the bursts with measured redshifts, the upper limits are compatible with a power-law extrapolation, when the intrinsic fluxes are evaluated taking into account the attenuation due to the scattering in the metagalactic radiation field.

Published
2007
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31. V346 Normae: First post-outburst observations of an FU Orionis star

Author

Alexander Kreplin, Stefan Kraus, John D. Monnier, A. Caratti o Garatti, Tim Naylor, Alicia Aarnio, R. Garcia-Lopez, and Gerd Weigelt

Subjects
Physics, 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, FU Orionis star, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics
Abstract

During their formation phase stars gain most of their mass in violent episodic accretion events, such as observed in FU Orionis (FUor) and EXor stars. V346 Normae is a well-studied FUor that underwent a strong outburst beginning in $\sim1980$. Here, we report photometric and spectroscopic observations which show that the visual/near-infrared brightness has decreased dramatically between the 1990s and 2010 (${\Delta}R\approx10.9^{\rm m}$, ${\Delta}J\approx7.8^{\rm m}$, ${\Delta}K\approx5.8^{\rm m}$). The spectral properties of this fading event cannot be explained with variable extinction alone, but indicate a drop in accretion rate by 2-3 orders of magnitude, marking the first time that a member of the FUor class has been observed to switch to a very low accretion phase. Remarkably, in the last few years (2011-2015) V346 Nor has brightened again at all near-infrared wavelengths, indicating the onset of a new outburst event. The observed behaviour might be consistent with the clustered luminosity bursts that have been predicted by recent gravitational instability and fragmentation models for the early stages of protostellar evolution. Given V346 Nor's unique characteristics (concerning outburst duration, repetition frequency, and spectroscopic diagnostics), our results also highlight the need for revisiting the FUor/EXor classification scheme., Comment: 5 pages, 2 figures, accepted at MNRAS Letters

Published
2016

32. Tracing jet emission at the base of a high-mass YSO. First AMBER/VLTI observations of the Br��emission in IRAS 13481-6124

Author

Stefan Kraus, Dieter Schertl, A. Caratti o Garatti, Karl-Heinz Hofmann, Rene D. Oudmaijer, Gerd Weigelt, R. Garcia Lopez, B. Stecklum, Tom Ray, Alexander Kreplin, W. J. de Wit, and Alberto Sanna

Subjects
Physics, 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, SIMBAD, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics - Astrophysics of Galaxies, 01 natural sciences, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR)
Abstract

To probe the circumstellar environment of IRAS 13481-6124, a 20 M_sun high-mass young stellar object (HMYSO) with a parsec-scale jet and accretion disc, we investigate the origin of its Br\gamma-emission line through NIR interferometry. We present the first AMBER/VLTI observations of the Br\gamma-emitting region in an HMYSO at R~1500. Our AMBER/VLTI observations reveal a spatially and spectrally resolved Br\gamma-line in emission with a strong P Cygni profile, indicating outflowing matter with a terminal velocity of ~500 km/s. Visibilities, differential phases, and closure phases are detected in our observations within the spectral line and in the adjacent continuum. Both total visibilities (continuum plus line emitting region) and pure-line visibilities indicate that the Br\gamma-emitting region is more compact (2-4 mas in diameter or ~6-13 au at 3.2 kpc) than the continuum-emitting region (~5.4 mas or ~17 au). The absorption feature is also spatially resolved at the longest baselines (81 and 85 m) and has a visibility that is slightly smaller than the continuum-emitting region. The differential phases at the four longest baselines display an \u2018S\u2019-shaped structure across the line, peaking in the blue- and red-shifted high-velocity components. The calibrated photocentre shifts are aligned with the known jet axis, i.e they are probably tracing an ionised jet. The high-velocity components (v_r~100-500 km/s) are located far from the source, whereas the low-velocity components (0-100 km/s) are observed to be closer, indicating a strong acceleration of the gas flow in the inner 10 au. Finally, a non-zero closure phase along the continuum is detected. By comparing our observations with the synthetic images of the continuum around 2.16 um, we confirm that this feature originates from the asymmetric brightness distribution of the continuum owing to the inclination of the inner disc., Comment: To be published in A&A letters

Published
2016
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33. P135Role of cytokines of the TGF beta family in the atrial structural remodelling underlying atrial fibrillation in aortic stenosis patients

Author

J F Nistal Herrera, V Exposito Garcia, M A Hurle Gonzalez, and R Garcia Lopez

Subjects
medicine.medical_specialty, Stenosis, Physiology, business.industry, Physiology (medical), Internal medicine, TGF beta signaling pathway, medicine, Cardiology, Atrial fibrillation, Cardiology and Cardiovascular Medicine, medicine.disease, business
Published
2018
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34. ATOMIC JETS FROM CLASS 0 SOURCES DETECTED BYSPITZER: THE CASE OF L1448-C

Author

T. Giannini, Brunella Nisini, Thomas P. Ray, M. De Luca, Odysseas Dionatos, Michael D. Smith, Christopher J. Davis, and R. Garcia Lopez

Subjects
Physics, Electron density, Jet (fluid), Silicon, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics (astro-ph), FOS: Physical sciences, chemistry.chemical_element, Flux, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Spectral line, chemistry, Space and Planetary Science, Ionization, Atomic physics, Astrophysics::Galaxy Astrophysics, Excitation, Line (formation)
Abstract

We present Spitzer-IRS spectra obtained along the molecular jet from the Class 0 source L1448-C (or L1448-mm). Atomic lines from the fundamental transitions of [FeII], [SiII] and [SI] have been detected showing, for the first time, the presence of an embedded atomic jet at low excitation. Pure rotational H$_2$ lines are also detected, and a decrease of the atomic/molecular emission ratio is observed within 1 arcmin from the driving source. Additional ground based spectra (UKIRT/UIST) were obtained to further constrain the H$_2$ excitation along the jet axis and, combined with the 0--0 lines, have been compared with bow-shock models. From the different line ratios, we find that the atomic gas is characterized by an electron density n_e ~ 200-1000 cm^{-3}, a temperature T_e < 2500 K and an ionization fraction, Comment: 31 pages, 8 figures, ApJ in press

Published
2009
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35. Constraints on the Steady and Pulsed Very High Energy Gamma‐Ray Emission from Observations of PSR B1951 \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape $+$ \end{document} 32/CTB 80 with the MAGIC Telescope

Author

J. Albert, E. Aliu, H. Anderhub, P. Antoranz, A. Armada, C. Baixeras, J. A. Barrio, H. Bartko, D. Bastieri, J. K. Becker, W. Bednarek, K. Berger, C. Bigongiari, A. Biland, R. K. Bock, P. Bordas, V. Bosch‐Ramon, T. Bretz, I. Britvitch, M. Camara, E. Carmona, A. Chilingarian, J. A. Coarasa, S. Commichau, J. L. Contreras, J. Cortina, M. T. Costado, V. Curtef, V. Danielyan, F. Dazzi, A. De Angelis, C. Delgado, R. de los Reyes, B. De Lotto, E. Domingo‐Santamaria, D. Dorner, M. Doro, M. Errando, M. Fagiolini, D. Ferenc, E. Fernandez, R. Firpo, J. Flix, M. V. Fonseca, L. Font, M. Fuchs, N. Galante, R. Garcia‐Lopez, M. Garczarczyk, M. Gaug, M. Giller, F. Goebel, D. Hakobyan, M. Hayashida, T. Hengstebeck, A. Herrero, K. Hirotani, D. Hohne, J. Hose, C.‐C. Hsu, P. Jacon, T. Jogler, R. Kosyra, D. Kranich, R. Kritzer, A. Laille, E. Lindfors, S. Lombardi, F. Longo, J. Lopez, M. Lopez, E. Lorenz, P. Majumdar, G. Maneva, K. Mannheim, O. Mansutti, M. Mariotti, M. Martinez, D. Mazin, C. Merck, M. Meucci, M. Meyer, J. M. Miranda, R. Mirzoyan, S. Mizobuchi, A. Moralejo, D. Nieto, K. Nilsson, J. Ninković, E. Ona‐Wilhelmi, N. Otte, I. Oya, D. Paneque, M. Panniello, R. Paoletti, J. M. Paredes, M. Pasanen, D. Pascoli, F. Pauss, R. Pegna, M. Persic, L. Peruzzo, A. Piccioli, M. Poller, E. Prandini, N. Puchades, A. Raymers, W. Rhode, M. Ribo, J. Rico, M. Rissi, A. Robert, S. Rugamer, A. Saggion, A. Sanchez, P. Sartori, V. Scalzotto, V. Scapin, R. Schmitt, T. Schweizer, M. Shayduk, K. Shinozaki, S. N. Shore, N. Sidro, A. Sillanpaa, D. Sobczyńska, A. Stamerra, L. S. Stark, L. Takalo, P. Temnikov, D. Tescaro, M. Teshima, N. Tonello, D. F. Torres, N. Turini, H. Vankov, V. Vitale, R. M. Wagner, T. Wibig, W. Wittek, F. Zandanel, R. Zanin, and J. Zapatero

Subjects
Physics, High energy, Nebula, Photon, Pulsar, Space and Planetary Science, Astrophysics::High Energy Astrophysical Phenomena, Gamma ray, Cutoff, Flux, Astronomy and Astrophysics, Astrophysics, Astrophysics::Galaxy Astrophysics
Abstract

We report on very high energy gamma-observations with the MAGIC Telescope of the pulsar PSR B1951+32 and its associated nebula, CTB 80. Our data constrain the cutoff energy of the pulsar to be less than 32 GeV, assuming the pulsed gamma-ray emission to be exponentially cut off. The upper limit on the flux of pulsed gamma-ray emission above 75 GeV is 4.3*10^-11 photons cm^-2 sec^-1, and the upper limit on the flux of steady emission above 140 GeV is 1.5*10^-11 photons cm^-2 sec^-1. We discuss our results in the framework of recent model predictions and other studies.

Published
2007
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36. Investigating 2MASS J06593158-0405277 : a FUor burst in a triple system?

Author

Stefan Kraus, Alexander Kreplin, J. Eislöffel, Gerd Weigelt, V. I. Shenavrin, Bringfried Stecklum, R. Garcia Lopez, Alexander Scholz, A. Caratti o Garatti, T. P. Ray, and University of St Andrews. School of Physics and Astronomy

Subjects
Triple system, Young stellar object, Astrophysics::High Energy Astrophysical Phenomena, NDAS, FOS: Physical sciences, Astrophysics, pre-main sequence [Stars], Astrophysics::Solar and Stellar Astrophysics, QB Astronomy, Astrophysics::Galaxy Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), formation [Stars], QC, QB, Physics, Very Large Telescope, individual: 2MASS J06593158-0405277 [Stars], Astronomy and Astrophysics, Circumstellar matter, Accretion (astrophysics), high angular resolution [Techniques], QC Physics, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, close [Binaries]
Abstract

FUor outbursts in young stellar objects (YSOs) are the most dramatic events among episodic accretion phenomena. The origin of these bursts is not clear: disk instabilities and/or disk perturbations by an external body being the most viable hypotheses. Here, we report our VLT/SINFONI high angular resolution AO-assisted observations of 2MASS J06593158-0405277, which is undergoing a recently discovered FUor outburst. Our observations reveal the presence of an extended disc-like structure around the FUor, a very low-mass companion (2MASS J06593158-0405277B) at ~100 au in projection, and, possibly, a third closer companion at ~11 au. These sources appear to be young, displaying accretion signatures. Assuming the components are physically linked, 2MASS J06593158-0405277 would then be one of the very few triple systems observed in FUors., Comment: Accepted for publication in the Astrophysical Journal Letters

Published
2015

37. Probing the accretion-ejection connection with VLTI/AMBER: High spectral resolution observations of the Herbig Ae star HD163296

Author

A. Caratti o Garatti, Dieter Schertl, Gerd Weigelt, R. Garcia Lopez, Karl-Heinz Hofmann, L. V. Tambovtseva, and V. P. Grinin

Subjects
Physics, 010308 nuclear & particles physics, Star formation, Gaussian, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astronomy and Astrophysics, Observable, Astrophysics, 01 natural sciences, Stars, symbols.namesake, Interferometry, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, 0103 physical sciences, symbols, Radiative transfer, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Spectral resolution, 010303 astronomy & astrophysics, Gaussian network model, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics
Abstract

Accretion and ejection are tightly connected and represent the fundamental mechanisms regulating star formation. However, the exact physical processes involved are not yet fully understood. We present high angular and spectral resolution observations of the Br Gamma emitting region in the Herbig Ae star HD163296 (MWC275) in order to probe the origin of this line and constrain the physical processes taking place at sub-AU scales in the circumstellar region. By means of VLTI-AMBER observations at high spectral resolution (R~12000), we studied interferometric visibilities, wavelength-differential phases, and closure phases across the Br Gamma line of HD163296. To constrain the physical origin of the Br Gamma line in Herbig Ae stars, all the interferometric observables were compared with the predictions of a line radiative transfer disc wind model. The measured visibilities clearly increase within the Br Gamma line, indicating that the Br Gamma emitting region is more compact than the continuum. By fitting a geometric Gaussian model to the continuum-corrected Br Gamma visibilities, we derived a compact radius of the Br Gamma emitting region of ~0.07+/-0.02AU (Gaussian half width at half maximum; or a ring-fit radius of ~0.08+/-0.02AU). To interpret the observations, we developed a magneto-centrifugally driven disc wind model. Our best disc wind model is able to reproduce, within the errors, all the interferometric observables and it predicts a launching region with an outer radius of ~0.04AU. However, the intensity distribution of the entire disc wind emitting region extends up to ~0.16AU. Our observations, along with a detailed modelling of the Br Gamma emitting region, suggest that most of the Br Gamma emission in HD163296 originates from a disc wind with a launching region that is over five times more compact than previous estimates of the continuum dust rim radius., Accepted for publication in A&A

Published
2015

38. Accretion rates in Herbig Ae stars

Author

R. Garcia Lopez, Leonardo Testi, Emilie Habart, and Antonella Natta

Subjects
Physics, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics (astro-ph), Gamma ray, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Radiation, Accretion (astrophysics), Spectral line, Medium resolution, Accretion rate, Stars, Space and Planetary Science, Ophiuchus, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics::Galaxy Astrophysics
Abstract

Accretion rates from disks around pre-main sequence stars are of importance for our understanding of planetary formation and disk evolution. We provide in this paper estimates of the mass accretion rates in the disks around a large sample of Herbig Ae stars. We obtained medium resolution 2 micron spectra and used the results to compute values of Macc from the measured luminosity of the Br_gamma emission line, using a well established correlation between L(Br_gamma) and the accretion luminosity Lacc. We find that 80% of the stars, all of which have evidence of an associated circumstellar disk, are accreting matter, with rates 3x10^{-9} < Macc} < 10^{-6} Msun/yr; for 7 objects, 6 of which are located on the ZAMS in the HR diagram, we do not detect any line emission. Few HAe stars (25%) have Macc>10^{-7} Msun/yr. In most HAe stars the accretion rate is sufficiently low that the gas in the inner disk, inside the dust evaporation radius, is optically thin and does not prevent the formation of a puffed-up rim, where dust is directly exposed to the stellar radiation. When compared to the Macc values found for lower-mass stars in the star forming regions Taurus and Ophiuchus, HAe stars have on average higher accretion rates than solar-mass stars; however, there is a lack of very strong accretors among them, probably due to the fact that they are on average older., To be published in Astronomy & Astrophysics

Published
2006
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39. POISSON project - III - Investigating the evolution of the mass accretion rate

Author

R. Garcia Lopez, T. Giannini, Simone Antoniucci, A. Caratti o Garatti, D. Lorenzetti, and Brunella Nisini

Subjects
Physics, Stellar mass, Serpens, Young stellar object, FOS: Physical sciences, Astronomy and Astrophysics, Context (language use), Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Poisson distribution, Accretion (astrophysics), Luminosity, symbols.namesake, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, symbols, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics::Galaxy Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Line (formation)
Abstract

As part of the POISSON project (Protostellar Optical-Infrared Spectral Survey on NTT), we present the results of the analysis of low-resolution NIR spectra 0.9-2.4 um) of two samples of YSOs in Lupus and Serpens (52 and 17 objects), with masses 0.1-2.0 Msun and ages from 10^5 to a few 10^7 yr. After determining the accretion parameters of the Lup and Ser targets by analysing their HI near-IR emission features, we added the results to those from previous regions (investigated in POISSON with the same methodology). We obtained a final catalogue (143 objects) of mass accretion rates (Macc) derived in a homogeneous fashion and analysed how Macc correlates with M* and how it evolves in time. We derived the accretion luminosity (Lacc) and Macc for Lup and Ser objects from the Br_gamma line by using relevant empirical relationships from the literature that connect HI line luminosity and Lacc. To minimise the biases and also for self-consistency, we re-derived mass and age for each source using the same set of evolutionary tracks. We observe a correlation MaccM*^2.2, similarly to what has previously been observed in several star-forming clouds. The time variation of Macc is roughly consistent with the expected evolution in viscous disks, with an asymptotic decay that behaves as t^-1.6. However, Macc values are characterised by a large scatter at similar ages and are on average higher than the predictions of viscous models. Although part of the scattering may be related to the employed empirical relationship and to uncertainties on the single measurements, the general distribution and decay trend of the Macc points are real. These findings might be indicative of a large variation in the initial mass of the disks, of fairly different viscous laws among disks, of varying accretion regimes, and of other mechanisms that add to the dissipation of the disks, such as photo-evaporation., Comment: 18 pages, 10 figures, accepted by A&A

Published
2014
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40. Discovery of very high energy gamma-ray emission from the low-frequency peaked BL Lacertae object BL Lacertae

Author

J. Albert, E. Aliu, H. Anderhub, P. Antoranz, A. Armada, C. Baixeras, J. A. Barrio, H. Bartko, D. Bastieri, J. K. Becker, W. Bednarek, K. Berger, C. Bigongiari, A. Biland, R. K. Bock, P. Bordas, V. Bosch Ramon, T. Bretz, I. Britvitch, M. Camara, E. Carmona, A. Chilingarian, J. A. Coarasa, S. Commichau, J. L. Contreras, J. Cortina, M. T. Costado, V. Curtef, V. Danielyan, F. Dazzi, A. D. Angelis, C. Delgado, R. D. L. Reyes, B. D. Lotto, E. Domingo Santamaria, D. Dorner, M. Doro, M. Errando, M. Fagiolini, D. Ferenc, E. Fernandez, R. Firpo, J. Flix, M. V. Fonseca, L. Font, M. Fuchs, N. Galante, R. Garcia Lopez, M. Garczarczyk, M. Gaug, M. Giller, F. Goebel, D. Hakobyan, M. Hayashida, T. Hengstebeck, A. Herrero, D. Hohne, J. Hose, C. C. Hsu, P. Jacon, T. Jogler, R. Kosyra, D. Kranich, R. Kritzer, A. Laille, E. Lindfors, S. Lombardi, J. Lopez, M. Lopez, E. Lorenz, P. Majumdar, G. Maneva, K. Mannheim, O. Mansutti, M. Mariotti, M. Martinez, D. Mazin, C. Merck, M. Meucci, M. Meyer, J. M. Miranda, R. Mirzoyan, S. Mizobuchi, A. Moralejo, K. Nilsson, J. Ninkovic, E. Ona Wilhelmi, N. Otte, I. Oya, D. Paneque, M. Panniello, R. Paoletti, J. M. Paredes, M. Pasanen, D. Pascoli, F. Pauss, R. Pegna, M. Persic, L. Peruzzo, A. Piccioli, M. Poller, E. Prandini, N. Puchades, A. Raymers, W. Rhode, M. Ribo, J. Rico, M. Rissi, A. Robert, S. Rugamer, A. Saggion, A. Sanchez, P. Sartori, V. Scalzotto, V. Scapin, R. Schmitt, T. Schweizer, M. Shayduk, K. Shinozaki, S. N. Shore, N. Sidro, A. Sillanpaa, D. Sobczynska, A. Stamerra, L. S. Stark, L. Takalo, P. Temnikov, D. Tescaro, M. Teshima, N. Tonello, D. F. Torres, N. Turini, H. Vankov, V. Vitale, R. M. Wagner, T. Wibig, W. Wittek, F. Zandanel, R. Zanin, J. Zapatero, LONGO, FRANCESCO, J., Albert, E., Aliu, H., Anderhub, P., Antoranz, A., Armada, C., Baixera, J. A., Barrio, H., Bartko, D., Bastieri, J. K., Becker, W., Bednarek, K., Berger, C., Bigongiari, A., Biland, R. K., Bock, P., Borda, V., Bosch Ramon, T., Bretz, I., Britvitch, M., Camara, E., Carmona, A., Chilingarian, J. A., Coarasa, S., Commichau, J. L., Contrera, J., Cortina, M. T., Costado, V., Curtef, V., Danielyan, F., Dazzi, A. D., Angeli, C., Delgado, R. D. L., Reye, B. D., Lotto, E., Domingo Santamaria, D., Dorner, M., Doro, M., Errando, M., Fagiolini, D., Ferenc, E., Fernandez, R., Firpo, J., Flix, M. V., Fonseca, L., Font, M., Fuch, N., Galante, R., Garcia Lopez, M., Garczarczyk, M., Gaug, M., Giller, F., Goebel, D., Hakobyan, M., Hayashida, T., Hengstebeck, A., Herrero, D., Hohne, J., Hose, C. C., Hsu, P., Jacon, T., Jogler, R., Kosyra, D., Kranich, R., Kritzer, A., Laille, E., Lindfor, S., Lombardi, Longo, Francesco, J., Lopez, M., Lopez, E., Lorenz, P., Majumdar, G., Maneva, K., Mannheim, O., Mansutti, M., Mariotti, M., Martinez, D., Mazin, C., Merck, M., Meucci, M., Meyer, J. M., Miranda, R., Mirzoyan, S., Mizobuchi, A., Moralejo, K., Nilsson, J., Ninkovic, E., Ona Wilhelmi, N., Otte, I., Oya, D., Paneque, M., Panniello, R., Paoletti, J. M., Parede, M., Pasanen, D., Pascoli, F., Pau, R., Pegna, M., Persic, L., Peruzzo, A., Piccioli, M., Poller, E., Prandini, N., Puchade, A., Raymer, W., Rhode, M., Ribo, J., Rico, M., Rissi, A., Robert, S., Rugamer, A., Saggion, A., Sanchez, P., Sartori, V., Scalzotto, V., Scapin, R., Schmitt, T., Schweizer, M., Shayduk, K., Shinozaki, S. N., Shore, N., Sidro, A., Sillanpaa, D., Sobczynska, A., Stamerra, L. S., Stark, L., Takalo, P., Temnikov, D., Tescaro, M., Teshima, N., Tonello, D. F., Torre, N., Turini, H., Vankov, V., Vitale, R. M., Wagner, T., Wibig, W., Wittek, F., Zandanel, R., Zanin, and J., Zapatero

Subjects
High energy, Photon, Flux, FOS: Physical sciences, Astrophysics, Low frequency, Observacions astronòmiques, Gamma ray astronomy, Galaxies: individual: BL Lacertae, Astronomia de raigs gamma, MAGIC (telescope), Physics, Astrophysics (astro-ph), Gamma ray, Astronomy and Astrophysics, Active Galactic Nuclei, Light curve, MAGIC telescope, Space and Planetary Science, Very High Energy Gamma-ray Astronomy, Electrónica, Física nuclear, Electricidad, BL Lac object, Astronomical observations
Abstract

The MAGIC collaboration observed BL Lacertae for 22.2 hr during 2005 August to December and for 26 hr during 2006 July to September. The source is the historical prototype and eponym of a class of low-frequency peaked BL Lacertae (LBL) objects. A very high energy (VHE) gamma-ray signal was discovered with a 5.1 sigma excess in the 2005 data. Above 200 GeV, an integral flux of 0.6+-0.2 x 10^(-11) cm^(-2) s^(-1) was measured, corresponding to approximately 3% of the Crab flux. The differential spectrum between 150 and 900 GeV is rather steep with a photon index of -3.6+-0.5. The light curve shows no significant variability during the observations in 2005. For the first time a clear detection of VHE gamma-ray emission from an LBL object was obtained with a signal below previous upper limits. The 2006 data show no significant excess. This drop in flux follows the observed trend in optical activity., Comment: Accepted for publication in ApJ Letters, 4 pages, 5 figures, Figure-5 revised, Minor corrections following the referee report

Published
2007

41. Bryostatin: A novel asymmetric synthesis of the C27C34 fragment starting from (R)-carvone as chiral template

Author

J. De Brabander, M. Vandewalle, B. A. Kulkarni, and R. Garcia‐Lopez

Subjects
Inorganic Chemistry, Bryostatins, Carvone, chemistry.chemical_compound, Fragment (logic), Chemistry, Stereochemistry, Organic Chemistry, Enantioselective synthesis, Physical and Theoretical Chemistry, Bryostatin, Combinatorial chemistry, Catalysis
Abstract

( R )-Carvone is a suitable chiral template for the synthesis of differently protected (4 S ,6 R ,7 R )-trihydroxy-1-octyne derivatives, the C 27 C 34 fragment of bryostatins. Also other potentially interesting chiral building blocks are described.

Published
1997
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42. LBT/LUCIFER near-infrared spectroscopy of PV Cephei. An outbursting young stellar object with an asymmetric jet

Author

A. Caratti o Garatti, Gerd Weigelt, L. V. Tambovtseva, John D. Ilee, H. E. Wheelwright, V. P. Grinin, R. Garcia Lopez, and University of St Andrews. School of Physics and Astronomy

Subjects
Young stellar object, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Context (language use), Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Luminosity, pre-main sequence [Stars], 0103 physical sciences, QB Astronomy, Astrophysics::Solar and Stellar Astrophysics, Emission spectrum, 010303 astronomy & astrophysics, Spectrograph, QC, Astrophysics::Galaxy Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), QB, Physics, jets and outflows [ISM], 010308 nuclear & particles physics, Near-infrared spectroscopy, Astronomy and Astrophysics, Large Binocular Telescope, Circumstellar matter, individual: PV Cep [Stars], Accretion (astrophysics), QC Physics, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics
Abstract

We present a detailed spectroscopic investigation of the young eruptive star PV Cep, to improve our understanding of its nature and characterise its circumstellar environment after its last outburst in 2004. The analysis of our medium-resolution spectroscopy in the near-IR (0.9-2.35 um), collected in 2012 at the Large Binocular Telescope with the IR spectrograph LUCIFER, allows us to infer the main stellar parameters (visual extinction, accretion luminosity, mass accretion and ejection rates), and model the inner disc, jet, and wind. The NIR spectrum displays several strong emission lines associated with accretion/ejection activity and circumstellar environment. Our analysis shows that the brightness of PV Cep is fading, as well as the mass accretion rate (2x10^-7 Msun/yr^-1 in 2012 vs ~5x10^-6 Msun/yr^-1 in 2004), which is more than one order of magnitude lower than in the outburst phase. Among the several emission lines, only the [FeII] intensity increased after the outburst. The observed [FeII] emission delineates blue- and red-shifted lobes, both with high- and low-velocity components, which trace an asymmetric jet and wind, respectively. The observed emission in the jet has a dynamical age of ~8 years, indicating that it was produced during the last outburst. The mass ejection rate in both lobes is 1.5x10^-7 Msun/yr^-1, approximately matching the high accretion rate observed during and immediately after the outburst . The observed jet/outflow asymmetries are consistent with an inhomogeneous medium. Our modelling of the CO emission hints at a small-scale gaseous disc ring, extending from ~0.2-0.4 AU to ~3 AU from the source, with an inner temperature of ~3000 K. Our HI lines modelling indicates that most of the observed emission comes from an expanding disc wind at Te=10000 K. The line profiles are strongly affected by scattering, disc screening, and outflow self-absorption., Comment: To be published in A&A

Published
2013
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43. POISSON project - II - A multi-wavelength spectroscopic and photometric survey of young protostars in L 1641

Author

Tom Ray, A. Caratti o Garatti, Brunella Nisini, Teresa Giannini, R. Garcia Lopez, J. Eislöffel, S. Cabrit, S. Antoniucci, and Dario Lorenzetti

Subjects
Physics, 010504 meteorology & atmospheric sciences, Young stellar object, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Spectral line, Accretion (astrophysics), Photometry (optics), Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, 0103 physical sciences, Protostar, Astrophysics::Solar and Stellar Astrophysics, Emission spectrum, Astrophysics::Earth and Planetary Astrophysics, Spectroscopy, 010303 astronomy & astrophysics, Stellar evolution, Astrophysics::Galaxy Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences
Abstract

Characterising stellar and circumstellar properties of embedded young stellar objects (YSOs) is mandatory for understanding the early stages of the stellar evolution. This task requires the combination of both spectroscopy and photometry, covering the widest possible wavelength range, to disentangle the various protostellar components and activities. As part of the POISSON project, we present a multi-wavelength spectroscopic and photometric investigation of embedded YSOs in L1641, aimed to derive the stellar parameters and evolutionary stages and to infer their accretion properties. Our database includes low-resolution optical-IR spectra from the NTT and Spitzer (0.6-40 um) and photometric data covering a spectral range from 0.4 to 1100 um, which allow us to construct the YSOs spectral energy distributions (SEDs) and to infer the main stellar parameters. The SED analysis allows us to group our 27 YSOs into nine Class I, eleven Flat, and seven Class II objects. However, on the basis of the derived stellar properties, only six Class I YSOs have an age of ~10^5 yr, while the others are older 5x10^5-10^6 yr), and, among the Flat sources, three out of eleven are more evolved objects (5x10^6-10^7 yr), indicating that geometrical effects can significantly modify the SED shapes. Inferred mass accretion rates (Macc) show a wide range of values (3.6x10^-9 to 1.2x10^-5 M_sun yr^-1), which reflects the age spread observed in our sample. Average values of mass accretion rates, extinction, and spectral indices decrease with the YSO class. The youngest YSOs have the highest Macc, whereas the oldest YSOs do not show any detectable jet activity in either images and spectra. We also observe a clear correlation among the YSO Macc, M*, and age, consistent with mass accretion evolution in viscous disc models., Comment: 61 pages, 16 figures; A&A in press

Published
2011
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46. ESPRESSO: A High Resolution Spectrograph for the Combined Coudé Focus of the VLT

Author

G. Avila, Stéphane Udry, Sandro D'Odorico, Denis Mégevand, Matteo Viel, M. R. Zapatero, P. Bonifacio, F. M. Zerbi, V. D'Odorico, S. Cristiani, Paolo Molaro, Shay Zucker, Sergei A. Levshakov, Jochen Liske, B. Carswell, Antonio Manescau, Jorge Pérez, E. Vanzella, Luca Pasquini, Hans Dekker, Martin G. Haehnelt, B. Delabre, P. Dimarcantonio, Michael T. Murphy, Paolo Spanò, M. Dessauges, G. Israelian, J. M. Herreros, Christophe Lovis, E. L. Martin, D. Queloz, R. Garcia-Lopez, N. C. Santos, Francesco Pepe, and Rafael Rebolo

Subjects
Espresso, Settore FIS/05 - Astronomia e Astrofisica, media_common.quotation_subject, Resolution (electron density), Astronomy, Art, Focus (optics), Spectrograph, media_common
Abstract

Luca Pasquini, A. Manescau, G. Avila, B. Delabre, H. Dekker, J. Liske, S. D’Odorico, F. Pepe, M. Dessauges, C. Lovis, D. Megevand, D. Queloz, S. Udry, S. Cristiani, P. Bonifacio, P. Dimarcantonio, V. D’Odorico, P. Molaro, E. Vanzella, M. Viel, M. Haehnelt, B. Carswell, M. Murphy, R. Garcia-Lopez, J.M. Herreros, J. Perez, M.R. Zapatero, R. Rebolo, G. Israelian, E. Martin, F. Zerbi, P. Spano, S. Levshakov, N. Santos and S. Zucker

Published
2009

47. CODEX: the high-resolution visual spectrograph for the E-ELT

Author

G. Avila, Rafael Rebolo, Paolo Spanò, Paolo Molaro, B. Delabre, Roberto López, Francesco Pepe, M. T. Osorio, Sandro D'Odorico, Luca Pasquini, M. Dessauges, Valentina D'Odorico, Antonio Manescau, R. Garcia-Lopez, Filippo Maria Zerbi, Piercarlo Bonifacio, Stéphane Udry, Stefano Cristiani, Hans Dekker, Didier Queloz, Martin G. Haehnelt, B. Carswell, Denis Mégevand, and Michel Mayor

Subjects
Physics, business.industry, Phase (waves), Slicing, Radial velocity, symbols.namesake, Optics, Planet, symbols, Calibration, Focus (optics), business, Spectrograph, Doppler effect
Abstract

A number of outstanding scientific problems require a high resolution, visual spectrograph at the E-ELT. Measuring the dynamics of the universe, finding earth-like planets with radial velocity techniques, determining the chemical evolution of the intergalactic medium and if physical constants varied in the past, all require a superior capability of measuring exceedingly small Doppler shifts. We have started a Phase A study for CODEX at the E-ELT. We present here the scientific cases, the requirements, the basic technical choices and trade offs, as well as a couple of design under evaluation. We aim at a super stable instrument, capable of obtaining a radial velocity precision of 2 cm/sec over several decades. It will be located at the coude focus. The design will make use of anamorphosis, pupil slicing, slanted VPH gratings and a novel calibration system based on laser frequency combs. Several CODEX-related R&D activities are running, and, in addition, a Call for Proposal for a precursor at the VLT has been issued.

Published
2008
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48. Codex

Author

Luca Pasquini, G. Avila, B. Délabre, H. Dekker, S. D’Odorico, J. Liske, A. Manescau, P. Bonifacio, S. Cristiani, V. D’Odorico, P. Molaro, E. Vanzella, P. Santin, M. Viel, M. Dessauges-Zavadsky, C. Lovis, M. Mayor, F. Pepe, D. Queloz, S. Udry, M. Haehnelt, M. Murphy, R. Garcia-Lopez, F. Bouchy, S. Levshakov, and S. Zucker

Published
2008
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49. AMBER/VLTI high spectral resolution observations of the Brγemitting region in HD 98922

Author

Dieter Schertl, Gerd Weigelt, L. V. Tambovtseva, R. Garcia Lopez, F. Massi, Martin Vannier, S. Lagarde, Fabien Malbet, Vladimir Grinin, Stefan Kraus, A. Caratti o Garatti, Karl-Heinz Hofmann, ITA, GBR, FRA, DEU, IRL, and RUS

Subjects
Physics, Brightness, Be star, Astrophysics::High Energy Astrophysical Phenomena, Spatially resolved, Compact disc, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Interferometry, Accretion rate, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Spectral resolution, Spectroscopy, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics
Abstract

We analyse the main physical parameters and the circumstellar environment of the young Herbig Be star HD 98922. We present AMBER/VLTI high spectral resolution (R =12000) interferometric observations across the Br$\gamma$ line, accompanied by UVES high-resolution spectroscopy and SINFONI-AO assisted near-infrared integral field spectroscopic data. To interpret our observations, we develop a magneto-centrifugally driven disc-wind model. Our analysis of the UVES spectrum shows that HD 98922 is a young (~5x10^5 yr) Herbig Be star (SpT=B9V), located at a distance of 440(+60-50) pc, with a mass accretion rate of ~9+/-3x10^(-7) M_sun yr^(-1). SINFONI K-band AO-assisted imaging shows a spatially resolved circumstellar disc-like region (~140 AU in diameter) with asymmetric brightness distribution. Our AMBER/VLTI UT observations indicate that the Br$\gamma$ emitting region (radius ~0.31+/-0.04 AU) is smaller than the continuum emitting region (inner dust radius ~0.7+/-0.2 AU), showing significant non-zero V-shaped differential phases (i.e. non S-shaped, as expected for a rotating disc). The value of the continuum-corrected pure Br$\gamma$ line visibility at the longest baseline (89 m) is ~0.8+/-0.1, i.e. the Br$\gamma$ emitting region is partially resolved. Our modelling suggests that the observed Br$\gamma$ line-emitting region mainly originates from a disc wind with a half opening angle of 30deg, and with a mass-loss rate of ~2x10(-7) M_sun yr^(-1). The observed V-shaped differential phases are reliably reproduced by combining a simple asymmetric continuum disc model with our Br$\gamma$ disc-wind model. The Br$\gamma$ emission of HD 98922 can be modelled with a disc wind that is able to approximately reproduce all interferometric observations if we assume that the intensity distribution of the dust continuum disc is asymmetric., Comment: Accepted for publication on Astronomy \& Astrophysics. High resolution figures published on the main journal (see Astronomy & Astrophysics: Forthcoming) or at www.researchgate.net/profile/Alessio_Caratti_o_Garatti/publications

Published
2015
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50. A near-infrared spectroscopic survey of massive jets towards extended green objects

Author

B. Stecklum, Alberto Sanna, H. Linz, R. Garcia Lopez, and A. Caratti o Garatti

Subjects
Physics, 010504 meteorology & atmospheric sciences, Space and Planetary Science, 0103 physical sciences, Near-infrared spectroscopy, Astronomy and Astrophysics, Astrophysics, 010303 astronomy & astrophysics, 01 natural sciences, 0105 earth and related environmental sciences
Published
2014
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