1,801 results
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2. The timing of relativistic proton acceleration in the 20 January 2005 flare, and other papers
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G. M. Simnett
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Proton (rocket family) ,Physics ,Timing error ,Solar flare ,Space and Planetary Science ,law ,Data needs ,Astronomy ,Astronomy and Astrophysics ,Acceleration (differential geometry) ,Astrophysics ,Flare ,law.invention - Abstract
In 2006 a timing error was discovered in the EPAM data from the ACE spacecraft, which has since been corrected. There are two publications where the interpretation of the data needs some revision on account of the error (Simnett 2006, AA Simnett et al. 2005, A&A, 440, 759). Here we publish the correct versions of the data and indicate where the discussion in the above papers needs modifying.
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- 2007
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3. New A&A editorial policy for papers about instrumentation
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Claude Bertout and Malcolm Walmsley
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Physics ,Space and Planetary Science ,Section (archaeology) ,Astrophysics::Instrumentation and Methods for Astrophysics ,Systems engineering ,Astronomy and Astrophysics ,Instrumentation (computer programming) ,Astrophysics ,Computer Science::Digital Libraries ,Physics::History of Physics ,Astronomical instrumentation - Abstract
Astronomy & Astrophysics introduces a new editorial policy for papers submitted to Section 13 (Astronomical Instrumentation).
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- 2006
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4. RX J0042.3+4115: a stellar mass black hole binary identified in M 31, and other papers
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J. P. Osborne, Robin Barnard, and Ulrich Kolb
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Physics ,Black hole ,Spectral index ,Accretion (meteorology) ,Stellar mass ,Space and Planetary Science ,X-ray binary ,Astronomy ,Astronomy and Astrophysics ,Stellar black hole ,Astrophysics ,Low Mass ,Power law - Abstract
In this work we have previously identified low mass X-ray binaries (LMXBs) in XMM-Newton observations of M 31 from their characteristic power density spectra (PDS). These PDS were characterised by a broken power law, with the spectral index changing from ∼0 to ∼1 at a break frequency in the range 0.01−1 Hz, and signify LMXBs in their low accretion-rate state (van der Klis 1994, ApJ, 92, 511). However, the observed PDS were false positives resulting from the improper treatment of non-simultaneous lightcurves; the corrected PDS are featureless (see Barnard et al. 2007, A&A, 469, 875, for details). As a result, there is no evidence for black hole primaries in the subjects of these papers.
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- 2006
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5. KiDS-1000 cosmology: Cosmic shear constraints and comparison between two point statistics
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Hendrik Hildebrandt, Fabian Köhlinger, Konrad Kuijken, Benjamin Giblin, Maciej Bilicki, Thomas Erben, Henk Hoekstra, Huanyuan Shan, Chieh-An Lin, Benjamin Stölzner, Tilman Tröster, Fedor Getman, Jelte T. A. de Jong, Jan Luca van den Busch, Lance Miller, Catherine Heymans, Marika Asgari, Chris Blake, Arun Kannawadi, Peter Schneider, Andrej Dvornik, Benjamin Joachimi, Angus H. Wright, Mario Radovich, Edwin A. Valentijn, and Astronomy
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Cosmology and Nongalactic Astrophysics (astro-ph.CO) ,CFHTLENS ,POWER SPECTRUM ,PARAMETER CONSTRAINTS ,Cosmic microwave background ,FOS: Physical sciences ,Lambda-CDM model ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,01 natural sciences ,Cosmology ,Bin ,Photometry (optics) ,symbols.namesake ,gravitational lensing: weak ,0103 physical sciences ,Statistics ,Methods ,DARK-MATTER ,Planck ,cosmological parameters ,010303 astronomy & astrophysics ,Observational ,ESTIMATORS ,Observations ,Physics ,Gravitational Lensing ,COSMIC cancer database ,010308 nuclear & particles physics ,Astronomy and Astrophysics ,GALAXIES ,MODEL ,CHALLENGE LIGHTCONE SIMULATION ,Gravitational lens ,Space and Planetary Science ,cosmology: observations ,symbols ,astro-ph.CO ,KIDS-450 ,large-scale structure of Universe ,methods: observational ,WEAK ,Cosmology and Nongalactic Astrophysics ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
We present cosmological constraints from a cosmic shear analysis of the fourth data release of the Kilo-Degree Survey (KiDS-1000), doubling the survey area with nine-band optical and near-infrared photometry with respect to previous KiDS analyses. Adopting a spatially flat $\Lambda$CDM model, we find $S_8 = \sigma_8 (\Omega_{\rm m}/0.3)^{0.5} = 0.759^{+0.024}_{-0.021}$ for our fiducial analysis, which is in $3\sigma$ tension with the prediction of the Planck Legacy analysis of the cosmic microwave background. We compare our fiducial COSEBIs (Complete Orthogonal Sets of E/B-Integrals) analysis with complementary analyses of the two-point shear correlation function and band power spectra, finding results to be in excellent agreement. We investigate the sensitivity of all three statistics to a number of measurement, astrophysical, and modelling systematics, finding our $S_8$ constraints to be robust and dominated by statistical errors. Our cosmological analysis of different divisions of the data pass the Bayesian internal consistency tests, with the exception of the second tomographic bin. As this bin encompasses low redshift galaxies, carrying insignificant levels of cosmological information, we find that our results are unchanged by the inclusion or exclusion of this sample., Comment: 33 pages, 14 figures, 7 tables, Accepted to be published in A&A. This paper is part of the KiDS-1000 series of papers: Heymans, Tr\"oster et al. (arXiv:2007.15632), Hildebrandt et al. (arXiv:2007.15635), Joachimi et al. (arXiv:2007.01844) and Giblin et al. (arXiv:2007.01845). Online KiDS-1000 talks can be viewed at http://kids.strw.leidenuniv.nl/KiDS-1000.php or the KiDS Consortium youtube page
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- 2021
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6. A large sub-Neptune transiting the thick-disk M4V TOI-2406
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Daniel Apai, H. Riesgo, Jon M. Jenkins, A. Schroeder, Khalid Barkaoui, George R. Ricker, Amaury H. M. J. Triaud, Aidan Gibbs, Tansu Daylan, Wen Ping Chen, R. Petrucci, Alex Bixel, K. Hesse, C. Murray, Keivan G. Stassun, Valérie Van Grootel, Sara Seager, Maximilian N. Günther, Laetitia Delrez, A. Burdanov, Laurence Sabin, Elise Furlan, Jennifer Dietrich, G. Melgoza, Lionel Garcia, Paul Gabor, Elsa Ducrot, Richard P. Schwarz, C. Gnilka, P. P. Pedersen, B.-O. Demory, R. Gore, M. A. Gómez-Muñoz, Prajwal Niraula, Didier Queloz, K. Lester, Y. Gómez Maqueo Chew, Karen A. Collins, Tianjun Gan, U. Schroffenegger, J. D. Twicken, I. Plauchu-Frayn, Carlos Guerrero, Michael Fausnaugh, P. F. Guillén, H. Serrano, R. D. Wells, Natalia Guerrero, N. Schanche, N. Scott, Mathilde Timmermans, C. A. Theissen, Steve B. Howell, Francisco J. Pozuelos, A. Landa, Samantha Thompson, Joshua N. Winn, James McCormac, Georgina Dransfield, Michaël Gillon, Emmanuel Jehin, R. Burn, S. Giacalone, M. Dévora-Pajares, Th. Henning, Adam J. Burgasser, J. de Wit, D. Sebastian, Mourad Ghachoui, F. Montalvo, D. W. Latham, D. R. Rodriguez, P. Chinchilla, and Benjamin V. Rackham
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Dwarf star ,010504 meteorology & atmospheric sciences ,Population ,FOS: Physical sciences ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,01 natural sciences ,individual: TOI-2406 [Stars] ,Neptune ,Planet ,0103 physical sciences ,Thick disk ,Astrophysics::Solar and Stellar Astrophysics ,education ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics ,0105 earth and related environmental sciences ,Physics ,Earth and Planetary Astrophysics (astro-ph.EP) ,education.field_of_study ,520 Astronomy ,photometric [Techniques] ,Astronomy and Astrophysics ,Exoplanet ,Radial velocity ,detection [Planets and satellites] ,Space and Planetary Science ,Astrophysics::Earth and Planetary Astrophysics ,Planetary mass ,Astrophysics - Earth and Planetary Astrophysics - Abstract
We thank the anonymous referee for their corrections and help in improving the paper. We warmly thank the entire technical staff of the Observatorio Astronomico Nacional at San Pedro Martir in Mexico for their unfailing support to SAINT-EX operations, namely: E. Cadena, T. Calvario, E. Colorado, B. Garcia, G. Guisa, A. Franco, L. Figueroa, B. Hernandez, J. Herrera, E. Lopez, E. Lugo, B. Martinez, J. M. Nunez, J. L. Ochoa, M. Pereyra, F. Quiroz, T. Verdugo, I. Zavala. B.V.R. thanks the Heising-Simons Foundation for support. Y.G.M.C acknowledges support from UNAM-PAPIIT IG-101321. B.-O. D. acknowledges support from the Swiss National Science Foundation (PP00P2-163967 and PP00P2-190080). R.B. acknowledges the support from the Swiss National Science Foundation under grant P2BEP2_195285. M.N.G. acknowledges support from MIT's Kavli Institute as a Juan Carlos Torres Fellow. A.H.M.J.T acknowledges funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme (grant agreement nffi 803193/BEBOP), from the MERAC foundation, and from the Science and Technology Facilities Council (STFC; grant nffi ST/S00193X/1). T.D. acknowledges support from MIT's Kavli Institute as a Kavli postdoctoral fellow Part of this work received support from the National Centre for Competence in Research PlanetS, supported by the Swiss National Science Foundation (SNSF). The research leading to these results has received funding from the ARC grant for Concerted Research Actions, financed by the Wallonia-Brussels Federation. TRAPPIST is funded by the Belgian Fund for Scientific Research (Fond National de la Recherche Scientifique, FNRS) under the grant FRFC 2.5.594.09.F, with the participation of the Swiss National Science Fundation (SNF). M.G. and E.J. are F.R.S.-FNRS Senior Research Associate. This publication benefits from the support of the French Community of Belgium in the context of the FRIA Doctoral Grant awarded to MT. We acknowledge the use of public TESS data from pipelines at the TESS Science Office and at the TESS Science Processing Operations Center. We acknowledge the use of public TESS Alert data from pipelines at the TESS Science Office and at the TESS Science Processing Operations Center. Resources supporting this work were provided by the NASA High-End Computing (HEC) Program through the NASA Advanced Supercomputing (NAS) Division at Ames Research Center for the production of the SPOC data products. Funding for the TESS mission is provided by NASA's Science Mission Directorate. This research has made use of the Exoplanet Follow-up Observation Program website, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. This paper includes data collected by the TESS mission that are publicly available from the Mikulski Archive for Space Telescopes (MAST). We thank the TESS GI program G03274 PI, Ryan Cloutier, for proposing the target of this work for 2-min-cadence observations in Sector 30. This work is based upon observations carried out at the Observatorio Astronomico Nacional on the Sierra de San Pedro Martir (OAN-SPM), Baja California, Mexico. This work makes use of observations from the LCOGT network. Part of the LCOGT telescope time was granted by NOIRLab through the Mid-Scale Innovations Program (MSIP). MSIP is funded by NSF. This work includes data collected at the Vatican Advanced Technology Telescope (VATT) on Mt. Graham. This paper includes data taken on the EDEN telescope network. We acknowledge support from the Earths in Other Solar Systems Project (EOS) and Alien Earths (grant numbers NNX15AD94G and 80NSSC21K0593), sponsored by NASA. Some of the observations in the paper made use of the High-Resolution Imaging instrument Zorro (Gemini program GS-2020B-LP-105). Zorro was funded by the NASA Exoplanet Exploration Program and built at the NASA Ames Research Center by Steve B. Howell, Nic Scott, Elliott P. Horch, and Emmett Quigley. Zorro was mounted on the Gemini South telescope of the international Gemini Observatory, a program of NSF's OIR Lab, which is managed by the Association of Universities for Research in Astronomy (AURA) under a cooperative agreement with the National Science Foundation. on behalf of the Gemini partnership: the National Science Foundation (United States), National Research Council (Canada), Agencia Nacional de Investigacion y Desarrollo (Chile), Ministerio de Ciencia, Tecnologia e Innovacion (Argentina), Ministerio da Ciencia, Tecnologia, Inovacoes e Comunicacoes (Brazil), and Korea Astronomy and Space Science Institute (Republic of Korea). This research has made use of the NASA Exoplanet Archive, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. This work made use of the following Python packages: astropy (Astropy Collaboration 2013, 2018), lightkurve (Lightkurve Collaboration 2018), matplotlib (Hunter 2007), pandas (Wes McKinney 2010), seaborn (Waskom & The Seaborn Development team 2021), scipy (Virtanen et al. 2020) and numpy (Harris et al. 2020)., Context. Large sub-Neptunes are uncommon around the coolest stars in the Galaxy and are rarer still around those that are metal-poor. However, owing to the large planet-to-star radius ratio, these planets are highly suitable for atmospheric study via transmission spectroscopy in the infrared, such as with JWST. Aims. Here we report the discovery and validation of a sub-Neptune orbiting the thick-disk, mid-M dwarf star TOI-2406. The star's low metallicity and the relatively large size and short period of the planet make TOI-2406 b an unusual outcome of planet formation, and its characterisation provides an important observational constraint for formation models. Methods. We first infer properties of the host star by analysing the star's near-infrared spectrum, spectral energy distribution, and Gaia parallax. We use multi-band photometry to confirm that the transit event is on-target and achromatic, and we statistically validate the TESS signal as a transiting exoplanet. We then determine physical properties of the planet through global transit modelling of the TESS and ground-based time-series data. Results. We determine the host to be a metal-poor M4 V star, located at a distance of 56 pc, with properties T-eff = 3100 +/- 75 K, M-* = 0.162 +/- 0.008M(circle dot), R-* = 0.202 +/- 0.011R(circle dot), and [Fe/H] = -0.38 +/- 0.07, and a member of the thick disk. The planet is a relatively large sub-Neptune for the M-dwarf planet population, with R-p = 2.94 +/- 0.17R(circle plus) and P= 3.077 d, producing transits of 2% depth. We note the orbit has a non-zero eccentricity to 3 sigma, prompting questions about the dynamical history of the system. Conclusions. This system is an interesting outcome of planet formation and presents a benchmark for large-planet formation around metal-poor, low-mass stars. The system warrants further study, in particular radial velocity follow-up to determine the planet mass and constrain possible bound companions. Furthermore, TOI-2406 b is a good target for future atmospheric study through transmission spectroscopy. Although the planet's mass remains to be constrained, we estimate the S/N using amass-radius relationship, ranking the system fifth in the population of large sub-Neptunes, with TOI-2406 b having a much lower equilibrium temperature than other spectroscopically accessible members of this population., Heising-Simons Foundation, Programa de Apoyo a Proyectos de Investigacion e Innovacion Tecnologica (PAPIIT), Universidad Nacional Autonoma de Mexico IG-101321, Swiss National Science Foundation (SNSF), European Commission PP00P2-163967 PP00P2-190080 P2BEP2_195285, MIT's Kavli Institute as a Juan Carlos Torres Fellow, European Research Council (ERC) nffi 803193/BEBOP, MERAC foundation, UK Research & Innovation (UKRI), Science & Technology Facilities Council (STFC), Science and Technology Development Fund (STDF) nffi ST/S00193X/1, MIT's Kavli Institute as a Kavli postdoctoral fellow, Australian Research Council, Fonds de la Recherche Scientifique - FNRS FRFC 2.5.594.09.F, French Community of Belgium in the context of the FRIA Doctoral Grant, NASA High-End Computing (HEC) Program through the NASA Advanced Supercomputing (NAS) Division at Ames Research Center, NASA's Science Mission Directorate, National Aeronautics and Space Administration under the Exoplanet Exploration Program, TESS GI program G03274, National Science Foundation (NSF), Earths in Other Solar Systems Project (EOS), Alien Earths - NASA NNX15AD94G 80NSSC21K0593, High-Resolution Imaging instrument Zorro (Gemini program) GS-2020B-LP-105, NASA Exoplanet Exploration Program, National Aeronautics & Space Administration (NASA)
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- 2021
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7. Type II supernovae from the Carnegie Supernova Project-I
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Santiago González-Gaitán, L. Martinez, Gastón Folatelli, Joseph P. Anderson, M. Orellana, Peter Hoeflich, F. Forster, Nicholas B. Suntzeff, Melina C. Bersten, Carlos Contreras, Mario Hamuy, Mark M. Phillips, Christopher R. Burns, Eric Hsiao, P. J. Pessi, M. D. Stritzinger, T. de Jaeger, Claudia P. Gutiérrez, Nidia Morrell, Lluís Galbany, K. Ertini, National Science Foundation (US), Consejo Nacional de Investigaciones Científicas y Técnicas (Argentina), Villum Fonden, Independent Research Fund Denmark, and Ministerio de Ciencia, Innovación y Universidades (España)
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High Energy Astrophysical Phenomena (astro-ph.HE) ,Physics ,Infrared ,general [Supernovae] ,Supernovae: general ,FOS: Physical sciences ,Astronomy and Astrophysics ,Blanketing ,Astrophysics ,Light curve ,Luminosity ,Astronomía ,Photometry (optics) ,Supernova ,Wavelength ,Astrophysics - Solar and Stellar Astrophysics ,Space and Planetary Science ,Astrophysics - High Energy Astrophysical Phenomena ,Solar and Stellar Astrophysics (astro-ph.SR) ,Line (formation) - Abstract
The present study is the first of a series of three papers where we characterise the type II supernovae (SNe~II) from the Carnegie Supernova Project-I to understand their diversity in terms of progenitor and explosion properties. In this first paper, we present bolometric light curves of 74 SNe~II. We outline our methodology to calculate the bolometric luminosity, which consists of the integration of the observed fluxes in numerous photometric bands ($uBgVriYJH$) and black-body (BB) extrapolations to account for the unobserved flux at shorter and longer wavelengths. BB fits were performed using all available broadband data except when line blanketing effects appeared. Photometric bands bluer than $r$ that are affected by line blanketing were removed from the fit, which makes near-infrared (NIR) observations highly important to estimate reliable BB extrapolations to the infrared. BB fits without NIR data produce notably different bolometric light curves, and therefore different estimates of SN~II progenitor and explosion properties when data are modelled. We present two methods to address the absence of NIR observations: (a) colour-colour relationships from which NIR magnitudes can be estimated using optical colours, and (b) new prescriptions for bolometric corrections as a function of observed SN~II colours. Using our 74 SN~II bolometric light curves, we provide a full characterisation of their properties based on several observed parameters. We measured magnitudes at different epochs, as well as durations and decline rates of different phases of the evolution. An analysis of the light-curve parameter distributions was performed, finding a wide range and a continuous sequence of observed parameters which is consistent with previous analyses using optical light curves., Comment: Accepted for publication in A&A
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- 2022
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8. Event Horizon Telescope imaging of the archetypal blazar 3C 279 at an extreme 20 microarcsecond resolution
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Robert Freund, N. W. Halverson, Benjamin R. Ryan, Paul Shaw, André Young, Andreas Eckart, A. Montaña, Michael Titus, Chen Yu Yu, Gertie Geertsema, Gao Feng, Ronald Grosslein, Ranjani Srinivasan, David Ball, Pablo Torne, Roberto Garcia, Hiroki Okino, Kotaro Moriyama, Chris Eckert, Lupin C.C. Lin, Geoffrey B. Crew, Vernon Fath, Freek Roelofs, David Sánchez-Arguelles, Luciano Rezzolla, Makoto Inoue, Michael Bremer, Jongsoo Kim, James Hoge, Michael Janssen, David M. Gale, Mel Rose, Jason Dexter, Do-Young Byun, J. G. A. Wouterloot, Rubén Herrero-Illana, Daniel C. M. Palumbo, Ta Shun Wei, Ching Tang Liu, Bradford Benson, Jadyn Anczarski, Patrick M. Koch, Ken Young, Jae-Young Kim, Minfeng Gu, Mislav Baloković, Mariafelicia De Laurentis, Laurent Loinard, A. Jiménez-Rosales, Tomohisa Kawashima, Nicolas Pradel, Heino Falcke, Olivier Gentaz, Dirk Muders, Shami Chatterjee, Britton Jeter, Rocco Lico, Craig Walther, David J. James, Homin Jiang, Michael H. Hecht, Gopal Narayanan, Qingwen Wu, Pierre Martin-Cocher, Michael A. Nowak, Alexander W. Raymond, Gregory Desvignes, Anne Kathrin Baczko, Chet Ruszczyk, Yutaka Hasegawa, Chao-Te Li, M. C. H. Wright, Andrew Nadolski, Alan P. Marscher, Christopher Beaudoin, Harriet Parsons, Peñalver Juan, Karl M. Menten, Silke Britzen, Frédéric Gueth, Shu Hao Chang, Andrew Chael, Daryl Haggard, Rodrigo Córdova Rosado, Ru-Sen Lu, Mansour Karami, José L. Gómez, Sang-Sung Lee, Tirupati K. Sridharan, Karl Friedrich Schuster, Ronald Hesper, Richard L. Plambeck, Iain Coulson, Jason SooHoo, Aristeidis Noutsos, Svetlana G. Jorstad, Li Ming Lu, James M. Cordes, David H. Hughes, Jonathan Weintroub, Chih-Wei Locutus Huang, Katherine L. Bouman, Roger J. Cappallo, Lijing Shao, Christiaan D. Brinkerink, John Kuroda, Ramesh Karuppusamy, Iniyan Natarajan, Jessica Dempsey, George Nystrom, John E. Carlstrom, Sera Markoff, Mark Kettenis, Neal R. Erickson, Jason W. Henning, R. Laing, Huang Lei, Kevin A. Dudevoir, Ilje Cho, William Stahm, Juan-Carlos Algaba, Junhan Kim, Hotaka Shiokawa, Martin P. McColl, James M. Moran, Chi-kwan Chan, Timothy C. Chuter, Thomas W. Folkers, Yi Chen, Christopher Greer, Lia Medeiros, C. Y. Kuo, Kuo Chang Han, Shoko Koyama, William Snow, Rurik A. Primiani, Sjoerd T. Timmer, F. Peter Schloerb, Stephen R. McWhirter, Fumie Tazaki, Norbert Wex, Ming-Tang Chen, Nimesh A. Patel, Aaron Faber, Mark Derome, Kazunori Akiyama, W. B. Everett, Hiroshi Nagai, Andrei Lobanov, Ignacio Ruiz, Pierre Christian, N. Phillips, David C. Forbes, Don Sousa, Michael Lindqvist, Christopher Risacher, Wen Ping Lo, Geoffrey C. Bower, Bart Ripperda, Dominique Broguiere, Maciek Wielgus, Antony A. Stark, Raquel Fraga-Encinas, Hiroaki Nishioka, Philippe Raffin, Hugo Messias, Feryal Özel, Jun Yi Koay, Buell T. Jannuzi, Sandra Bustamente, Roberto Neri, Jinchi Hao, Ye-Fei Yuan, Garrett K. Keating, Lynn D. Matthews, Avery E. Broderick, Mark G. Rawlings, Ciriaco Goddi, Tod R. Lauer, Kamal Souccar, Alan L. Roy, S. Navarro, Luis C. Ho, Timothy Norton, Roger Brissenden, Doosoo Yoon, Jongho Park, Richard Lacasse, Paul T. P. Ho, Derek Ward-Thompson, Atish Kamble, Akihiko Hirota, S. Sánchez, D. A. Graham, Vincent Piétu, Kyle D. Massingill, M. Zeballos, Mahito Sasada, Hideo Ogawa, Ziri Younsi, Chih Cheng Chang, Alejandro F. Sáez-Madain, Christian M. Fromm, Ramesh Narayan, Shuichiro Tsuda, Ryan Berthold, Gibwa Musoke, Laura Vertatschitsch, Masanori Nakamura, Remo P. J. Tilanus, Cornelia Müller, Kimihiro Kimura, Roman Gold, Venkatessh Ramakrishnan, Yuzhu Cui, Frederick K. Baganoff, Alan R. Whitney, Aleksandar Popstefanija, Helge Rottmann, Yuan Feng, Ralph Eatough, Tuomas Savolainen, Neil M. Nagar, Alexander Allardi, M. Mora-Klein, Thomas Bronzwaer, Mark Gurwell, Bong Won Sohn, Ivan Marti-Vidal, Chih Chiang Han, Hung Yi Pu, Yan-Rong Li, Shan Shan Zhao, Song Chu Chang, Zhi-Qiang Shen, John F. C. Wardle, Carsten Kramer, Koushik Chatterjee, Wagner Jan, Tomoaki Oyama, Ray Blundell, Motoki Kino, Alan E. E. Rogers, Rebecca Azulay, Jordy Davelaar, Tyler Trent, Satoki Matsushita, Kazi L.J. Rygl, Shuo Zhang, John E. Barrett, Peter Oshiro, Ryan Chilson, Jorge A. Preciado-López, Daniel Michalik, Peter Galison, Uwe Bach, Ilse van Bemmel, Pim Schellart, Michael D. Johnson, Jiang Wu, J. Anton Zensus, S. A. Dzib, Arturo I. Gómez-Ruiz, Meyer Zhao Zheng, David John, Dimitrios Psaltis, Daniel P. Marrone, M. Poirier, Shiro Ikeda, Ralph G. Marson, A. Hernandez-Gomez, Sven Dornbusch, George Reiland, Mareki Honma, J. Blanchard, Ed Fomalont, Taehyun Jung, Izumi Mizuno, Monika Moscibrodzka, Vincent L. Fish, Matthew R. Dexter, Paul Tiede, Rodrigo Amestica, Nicholas R. MacDonald, Gisela N. Ortiz-León, Colin J. Lonsdale, Callie Matulonis, Charles F. Gammie, Per Friberg, Boris Georgiev, W. Boland, Ramprasad Rao, Guang-Yao Zhao, Joseph R. Farah, Zhiyuan Li, Hector Olivares, Sara Issaoun, Elisabetta Liuzzo, C. M. Violette Impellizzeri, Michael Kramer, Oliver Porth, Thomas P. Krichbaum, Dominic W. Pesce, Daniel R. van Rossum, David R. Smith, Robert Wharton, Kuan Yu Liu, David P. Woody, Arash Roshanineshat, Sheperd S. Doeleman, Chung Chen Chen, Ziyan Zhu, Ue-Li Pen, Yosuke Mizuno, Prather Ben, Sascha Trippe, Walter Alef, Liu Kuo, Alexandra S. Rahlin, William Montgomerie, George N. Wong, Jirong Mao, Kazuhiro Hada, Efthalia Traianou, John Conway, Remi Sassella, Eduardo Ros, Kevin M. Silva, Derek Kubo, E. Castillo-Domínguez, Huib Jan van Langevelde, Keiichi Asada, Des Small, Joseph Neilsen, Chi H. Nguyen, Chunchong Ni, Yusuke Kono, Ryan Keisler, Paul Yamaguchi, Lindy Blackburn, Erik M. Leitch, Roger Deane, Lucy M. Ziurys, K. T. Story, Joseph Crowley, Nathan Whitehorn, Stefan Heyminck, Kenji Toma, Antxon Alberdi, Yau De Huang, Dan Bintley, Y Kim, J., Krichbaum, T. P., Broderick, A. E., Wielgus, M., Blackburn, L., Gomez, J. -L., Johnson, M. D., Bouman, K. L., Chael, A., Akiyama, K., Jorstad, S., Marscher, A. P., Issaoun, S., Janssen, M., Chan, C. -K., Savolainen, T., Pesce, D. W., Ozel, F., De Laurentis, M., Deane, R., Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Instituto de RadioAstronomía Milimétrica (IRAM), Event Horizon Telescope, Ministerio de Economía y Competitividad (España), European Commission, National Aeronautics and Space Administration (US), Max Planck Institute for Radio Astronomy, Perimeter Institute for Theoretical Physics, Harvard University, CSIC, Princeton University, Boston University, Radboud University Nijmegen, University of Arizona, Anne Lähteenmäki Group, Academia Sinica - Institute of Astronomy and Astrophysics, Massachusetts Institute of Technology, East Asian Observatory, Nederlandse Onderzoekschool voor Astronomie, Academia Sinica, Institut de Radio Astronomie Millimétrique, Korea Astronomy and Space Science Institute, University of Chicago, Cornell University, University of Amsterdam, CAS - Shanghai Astronomical Observatory, Chalmers University of Technology, National Astronomical Observatory of Japan, University of Naples Federico II, University of Pretoria, University of Colorado Boulder, National Radio Astronomy Observatory, Goethe University Frankfurt, University of Illinois at Urbana-Champaign, University of Waterloo, Instituto Nacional de Astrofisica Optica y Electronica, University of Groningen, Peking University, Max Planck Institute for Extraterrestrial Physics, Joint Institute for VLBI in Europe, California Institute of Technology, National Sun Yat-sen University, National Optical Astronomy Observatory, CAS - Institute of High Energy Physics, Nanjing University, INAF Istituto di Radioastronomia, Instituto de Radioastronomía y Astrofísica, CAS - National Astronomical Observatories, Universidad de Valencia, Universidad de Concepción, University of Massachusetts, Rhodes University, University of California Berkeley, Los Alamos National Laboratory, IRAM, Tohoku University, Seoul National University, Brandeis University, University of Central Lancashire, Huazhong University of Science and Technology, University of Science and Technology of China, University of Vermont, Villanova University, United States Department of Energy, Western University, Royal Netherlands Meteorological Institute, McGill University, Osaka Prefecture University, European Southern Observatory Santiago, University of Manchester, National Radio Astronomy Observatory Socorro, Rochester Institute of Technology, Washington University St. Louis, Systems and Technology Research, Georgia Institute of Technology, Stanford University, University of California Los Angeles, Department of Electronics and Nanoengineering, Aalto-yliopisto, Aalto University, Astronomy, High Energy Astrophys. & Astropart. Phys (API, FNWI), and Gravitation and Astroparticle Physics Amsterdam
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ACTIVE GALACTIC NUCLEI ,Brightness ,Active galactic nucleus ,active [Galaxies] ,Astrophysics::High Energy Astrophysical Phenomena ,Astronomy ,galaxies: active ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,01 natural sciences ,Submillimeter Array ,FLOWS ,SCALE CIRCULAR-POLARIZATION ,0103 physical sciences ,Very-long-baseline interferometry ,Blazar ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics ,Physics ,Event Horizon Telescope ,[PHYS]Physics [physics] ,Jet (fluid) ,010308 nuclear & particles physics ,Astronomy and Astrophysics ,FLARE ,galaxies: jets ,individual: 3C 279 [Galaxies] ,LONG ,VARIABILITY ,galaxies: individual: 3C 279 ,GAMMA-RAY ,QUASARS ,13. Climate action ,Space and Planetary Science ,techniques: interferometric ,Brightness temperature ,ACCRETION DISKS ,interferometric [Techniques] ,jets [Galaxies] ,RELATIVISTIC JETS ,[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph] - Abstract
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Open Access funding provided by Max Planck Society.--All authors: Kim, Jae-Young; Krichbaum, Thomas P.; Broderick, Avery E.; Wielgus, Maciek; Blackburn, Lindy; Gómez, José L.; Johnson, Michael D.; Bouman, Katherine L.; Chael, Andrew; Akiyama, Kazunori; Jorstad, Svetlana; Marscher, Alan P.; Issaoun, Sara; Janssen, Michael; Chan, Chi-kwan; Savolainen, Tuomas; Pesce, Dominic W.; Özel, Feryal; Alberdi, Antxon; Alef, Walter Asada, Keiichi; Azulay, Rebecca; Baczko, Anne-Kathrin; Ball, David; Baloković, Mislav; Barrett, John; Bintley, Dan; Boland, Wilfred; Bower, Geoffrey C.; Bremer, Michael; Brinkerink, Christiaan D.; Brissenden, Roger; Britzen, Silke; Broguiere, Dominique; Bronzwaer, Thomas; Byun, Do-Young; Carlstrom, John E.; Chatterjee, Shami; Chatterjee, Koushik; Chen, Ming-Tang; Chen, Yongjun; Cho, Ilje; Christian, Pierre; Conway, John E.; Cordes, James M.; Crew, Geoffrey B.; Cui, Yuzhu; Davelaar, Jordy; De Laurentis, Mariafelicia; Deane, Roger; Dempsey, Jessica; Desvignes, Gregory; Dexter, Jason; Doeleman, Sheperd S.; Eatough, Ralph P.; Falcke, Heino; Fish, Vincent L.; Fomalont, Ed; Fraga-Encinas, Raquel; Friberg, Per; Fromm, Christian M.; Galison, Peter; Gammie, Charles F.; García, Roberto; Gentaz, Olivier; Georgiev, Boris; Goddi, Ciriaco; Gold, Roman; Gómez-Ruiz, Arturo I.; Gu, Minfeng; Gurwell, Mark; Hada, Kazuhiro; Hecht, Michael H.; Hesper, Ronald; Ho, Luis C.; Ho, Paul; Honma, Mareki; Huang, Chih-Wei L.; Huang, Lei; Hughes, David H.; Ikeda, Shiro; Inoue, Makoto; James, David J.; Jannuzi, Buell T.; Jeter, Britton; Jiang, Wu; Jimenez-Rosales, Alejandra; Jung, Taehyun; Karami, Mansour; Karuppusamy, Ramesh; Kawashima, Tomohisa; Keating, Garrett K.; Kettenis, Mark; Kim, Junhan; Kim, Jongsoo; Kino, Motoki; Koay, Jun Yi; Koch, Patrick M.; Koyama, Shoko; Kramer, Michael; Kramer, Carsten; Kuo, Cheng-Yu; Lauer, Tod R.; Lee, Sang-Sung; Li, Yan-Rong; Li, Zhiyuan; Lindqvist, Michael; Lico, Rocco; Liu, Kuo; Liuzzo, Elisabetta; Lo, Wen-Ping; Lobanov, Andrei P.; Loinard, Laurent; Lonsdale, Colin; Lu, Ru-Sen; MacDonald, Nicholas R.; Mao, Jirong; Markoff, Sera; Marrone, Daniel P.; Martí-Vidal, Iván; Matsushita, Satoki; Matthews, Lynn D.; Medeiros, Lia; Menten, Karl M.; Mizuno, Yosuke; Mizuno, Izumi; Moran, James M.; Moriyama, Kotaro; Moscibrodzka, Monika; Musoke, Gibwa; Müller, Cornelia; Nagai, Hiroshi; Nagar, Neil M.; Nakamura, Masanori; Narayan, Ramesh; Narayanan, Gopal; Natarajan, Iniyan; Neri, Roberto; Ni, Chunchong; Noutsos, Aristeidis; Okino, Hiroki; Olivares, Héctor; Ortiz-León, Gisela N.; Oyama, Tomoaki; Palumbo, Daniel C. M.; Park, Jongho; Patel, Nimesh; Pen, Ue-Li; Piétu, Vincent; Plambeck, Richard; PopStefanija, Aleksandar; Porth, Oliver; Prather, Ben; Preciado-López, Jorge A.; Psaltis, Dimitrios; Pu, Hung-Yi; Ramakrishnan, Venkatessh; Rao, Ramprasad; Rawlings, Mark G.; Raymond, Alexander W.; Rezzolla, Luciano; Ripperda, Bart; Roelofs, Freek; Rogers, Alan; Ros, Eduardo; Rose, Mel; Roshanineshat, Arash; Rottmann, Helge; Roy, Alan L.; Ruszczyk, Chet; Ryan, Benjamin R.; Rygl, Kazi L. J.; Sánchez, Salvador; Sánchez-Arguelles, David; Sasada, Mahito; Schloerb, F. Peter; Schuster, Karl-Friedrich; Shao, Lijing; Shen, Zhiqiang; Small, Des; Sohn, Bong Won; SooHoo, Jason; Tazaki, Fumie; Tiede, Paul; Tilanus, Remo P. J.; Titus, Michael; Toma, Kenji; Torne, Pablo; Trent, Tyler; Traianou, Efthalia; Trippe, Sascha; Tsuda, Shuichiro; van Bemmel, Ilse; van Langevelde, Huib Jan; van Rossum, Daniel R.; Wagner, Jan; Wardle, John; Ward-Thompson, Derek; Weintroub, Jonathan; Wex, Norbert; Wharton, Robert; Wong, George N.; Wu, Qingwen; Yoon, Doosoo; Young, André; Young, Ken; Younsi, Ziri; Yuan, Feng; Yuan, Ye-Fei; Zensus, J. Anton; Zhao, Guangyao; Zhao, Shan-Shan; Zhu, Ziyan; Algaba, Juan-Carlos; Allardi, Alexander; Amestica, Rodrigo; Anczarski, Jadyn; Bach, Uwe; Baganoff, Frederick K.; Beaudoin, Christopher; Benson, Bradford A.; Berthold, Ryan; Blanchard, Jay M.; Blundell, Ray; Bustamente, Sandra; Cappallo, Roger; Castillo-Domínguez, Edgar; Chang, Chih-Cheng; Chang, Shu-Hao; Chang, Song-Chu; Chen, Chung-Chen; Chilson, Ryan; Chuter, Tim C.; Rosado, Rodrigo Córdova; Coulson, Iain M.; Crowley, Joseph; Derome, Mark; Dexter, Matthew; Dornbusch, Sven; Dudevoir, Kevin A.; Dzib, Sergio A.; Eckart, Andreas; Eckert, Chris; Erickson, Neal R.; Everett, Wendeline B.; Faber, Aaron; Farah, Joseph R.; Fath, Vernon; Folkers, Thomas W.; Forbes, David C.; Freund, Robert; Gale, David M.; Gao, Feng; Geertsema, Gertie; Graham, David A.; Greer, Christopher H.; Grosslein, Ronald; Gueth, Frédéric; Haggard, Daryl; Halverson, Nils W.; Han, Chih-Chiang; Han, Kuo-Chang; Hao, Jinchi; Hasegawa, Yutaka; Henning, Jason W.; Hernández-Gómez, Antonio; Herrero-Illana, Rubén; Heyminck, Stefan; Hirota, Akihiko; Hoge, James; Huang, Yau-De; Violette Impellizzeri, C. M.; Jiang, Homin; John, David; Kamble, Atish; Keisler, Ryan; Kimura, Kimihiro; Kono, Yusuke; Kubo, Derek; Kuroda, John; Lacasse, Richard; Laing, Robert A.; Leitch, Erik M.; Li, Chao-Te; Lin, Lupin C. -C.; Liu, Ching-Tang; Liu, Kuan-Yu; Lu, Li-Ming; Marson, Ralph G.; Martin-Cocher, Pierre L.; Massingill, Kyle D.; Matulonis, Callie; McColl, Martin P.; McWhirter, Stephen R.; Messias, Hugo; Meyer-Zhao, Zheng; Michalik, Daniel; Montaña, Alfredo; Montgomerie, William; Mora-Klein, Matias; Muders, Dirk; Nadolski, Andrew; Navarro, Santiago; Neilsen, Joseph; Nguyen, Chi H.; Nishioka, Hiroaki; Norton, Timothy; Nowak, Michael A.; Nystrom, George; Ogawa, Hideo; Oshiro, Peter; Oyama, Tomoaki; Parsons, Harriet; Peñalver, Juan; Phillips, Neil M.; Poirier, Michael; Pradel, Nicolas; Primiani, Rurik A.; Raffin, Philippe A.; Rahlin, Alexandra S.; Reiland, George; Risacher, Christopher; Ruiz, Ignacio; Sáez-Madaín, Alejandro F.; Sassella, Remi; Schellart, Pim; Shaw, Paul; Silva, Kevin M.; Shiokawa, Hotaka; Smith, David R.; Snow, William; Souccar, Kamal; Sousa, Don; Sridharan, Tirupati K.; Srinivasan, Ranjani; Stahm, William; Stark, Antony A.; Story, Kyle; Timmer, Sjoerd T.; Vertatschitsch, Laura; Walther, Craig; Wei, Ta-Shun; Whitehorn, Nathan; Whitney, Alan R.; Woody, David P.; Wouterloot, Jan G. A.; Wright, Melvin; Yamaguchi, Paul; Yu, Chen-Yu; Zeballos, Milagros; Zhang, Shuo; Ziurys, Lucy; Event Horizon Telescope Collaboration, 3C 279 is an archetypal blazar with a prominent radio jet that show broadband flux density variability across the entire electromagnetic spectrum. We use an ultra-high angular resolution technique - global Very Long Baseline Interferometry (VLBI) at 1.3mm (230 GHz) - to resolve the innermost jet of 3C 279 in order to study its fine-scale morphology close to the jet base where highly variable-ray emission is thought to originate, according to various models. The source was observed during four days in April 2017 with the Event Horizon Telescope at 230 GHz, including the phased Atacama Large Millimeter/submillimeter Array, at an angular resolution of ∼20 μas (at a redshift of z = 0:536 this corresponds to ∼0:13 pc ∼ 1700 Schwarzschild radii with a black hole mass MBH = 8 × 108 M⊙). Imaging and model-fitting techniques were applied to the data to parameterize the fine-scale source structure and its variation.We find a multicomponent inner jet morphology with the northernmost component elongated perpendicular to the direction of the jet, as imaged at longer wavelengths. The elongated nuclear structure is consistent on all four observing days and across diffierent imaging methods and model-fitting techniques, and therefore appears robust. Owing to its compactness and brightness, we associate the northern nuclear structure as the VLBI "core". This morphology can be interpreted as either a broad resolved jet base or a spatially bent jet.We also find significant day-to-day variations in the closure phases, which appear most pronounced on the triangles with the longest baselines. Our analysis shows that this variation is related to a systematic change of the source structure. Two inner jet components move non-radially at apparent speeds of ∼15 c and ∼20 c (∼1:3 and ∼1:7 μas day-1, respectively), which more strongly supports the scenario of traveling shocks or instabilities in a bent, possibly rotating jet. The observed apparent speeds are also coincident with the 3C 279 large-scale jet kinematics observed at longer (cm) wavelengths, suggesting no significant jet acceleration between the 1.3mm core and the outer jet. The intrinsic brightness temperature of the jet components are ≤1010 K, a magnitude or more lower than typical values seen at ≥7mm wavelengths. The low brightness temperature and morphological complexity suggest that the core region of 3C 279 becomes optically thin at short (mm) wavelengths. © J.-Y. Kim et al. 2020., The authors of the present paper thank the following organizations and programs: the Academy of Finland (projects 274477, 284495, 312496); the Advanced European Network of E-infrastructures for Astronomy with the SKA (AENEAS) project, supported by the European Commission Framework Programme Horizon 2020 Research and Innovation action under grant agreement 731016; the Alexander von Humboldt Stiftung; the Black Hole Initiative at Harvard University, through a grant (60477) from the John Templeton Foundation; the China Scholarship Council; Comision Nacional de Investigacion Cientifica y Tecnologica (CONICYT, Chile, via PIA ACT172033, Fondecyt projects 1171506 and 3190878, BASAL AFB-170002, ALMA-conicyt 31140007); Consejo Nacional de Ciencia y Tecnologia (CONACYT, Mexico, projects 104497, 275201, 279006, 281692); the Delaney Family via the Delaney Family John A. Wheeler Chair at Perimeter Institute; Direccion General de Asuntos del Personal Academico -Universidad Nacional Autonoma de Mexico (DGAPA -UNAM, project IN112417); the European Research Council Synergy Grant "BlackHoleCam: Imaging the Event Horizon of Black Holes" (grant 610058); the Generalitat Valenciana postdoctoral grant APOSTD/2018/177 and GenT Program (project CIDEGENT/2018/021); the Gordon and Betty Moore Foundation (grants GBMF-3561, GBMF-5278); the Istituto Nazionale di Fisica Nucleare (INFN) sezione di Napoli, iniziative specifiche TEONGRAV; the International Max Planck Research School for Astronomy and Astrophysics at the Universities of Bonn and Cologne; the Jansky Fellowship program of the National Radio Astronomy Observatory (NRAO); the Japanese Government (Monbukagakusho: MEXT) Scholarship; the Japan Society for the Promotion of Science (JSPS) Grant-inAid for JSPS Research Fellowship (JP17J08829); the Key Research Program of Frontier Sciences, Chinese Academy of Sciences (CAS, grants QYZDJSSW-SLH057, QYZDJ-SSW-SYS008, ZDBS-LY-SLH011); the Leverhulme Trust Early Career Research Fellowship; the Malaysian Fundamental Research Grant Scheme (FRGS, grant FRGS/1/2019/STG02/UM/02/6); the Max-PlanckGesellschaft (MPG); the Max Planck Partner Group of the MPG and the CAS; the MEXT/JSPS KAKENHI (grants 18KK0090, JP18K13594, JP18K03656, JP18H03721, 18K03709, 18H01245, 25120007); the MIT International Science and Technology Initiatives (MISTI) Funds; the Ministry of Science and Technology (MOST) of Taiwan (105-2112-M-001-025-MY3, 106-2112-M-001-011, 106-2119-M-001-027, 107-2119-M-001-017, 107-2119-M-001-020, and 107-2119-M-110-005); the National Aeronautics and Space Administration (NASA, Fermi Guest Investigator grant 80NSSC17K0649 and Hubble Fellowship grant HST-HF2-51431.001-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc. r , for NASA, under contract NAS5-26555); the National Institute of Natural Sciences (NINS) of Japan; the National Key Research and Development Program of China (grant 2016YFA0400704, 2016YFA0400702); the National Science Foundation (NSF, grants AST-0096454, AST-0352953, AST-0521233, AST-0705062, AST-0905844, AST-0922984, AST-1126433, AST-1140030, DGE-1144085, AST-1207704, AST-1207730, AST-1207752, MRI-1228509, OPP-1248097, AST-1310896, AST-1312651, AST-1337663, AST-1440254, AST-1555365, AST-1715061, AST-1615796, AST-1716327, OISE-1743747, AST-1816420); the Natural Science Foundation of China (grants 11573051, 11633006, 11650110427, 10625314, 11721303, 11725312, 11933007); the Natural Sciences and Engineering Research Council of Canada (NSERC, including a Discovery Grant and the NSERC Alexander Graham Bell Canada Graduate Scholarships-Doctoral Program); the National Youth Thousand Talents Program of China; the National Research Foundation of Korea (the Global PhD Fellowship Grant: grants NRF-2015H1A2A1033752, 2015-R1D1A1A01056807, the Korea Research Fellowship Program: NRF-2015H1D3A1066561); the Netherlands Organization for Scientific Research (NWO) VICI award (grant 639.043.513) and Spinoza Prize SPI 78-409; the New Scientific Frontiers with Precision Radio Interferometry Fellowship awarded by the South African Radio Astronomy Observatory (SARAO), which is a facility of the National Research Foundation (NRF), an agency of the Department of Science and Technology (DST) of South Africa; the Onsala Space Observatory (OSO) national infrastructure, for the provisioning of its facilities/observational support (OSO receives funding through the Swedish Research Council under grant 2017-00648) the Perimeter Institute for Theoretical Physics (research at Perimeter Institute is supported by the Government of Canada through the Department of Innovation, Science and Economic Development and by the Province of Ontario through the Ministry of Research, Innovation and Science); the Russian Science Foundation (grant 17-12-01029); the Spanish Ministerio de Economia y Competitividad (grants PGC2018-098915-B-C21, AYA201680889-P); the State Agency for Research of the Spanish MCIU through the "Center of Excellence Severo Ochoa" award for the Instituto de Astrofisica de Andalucia (SEV-2017-0709); the Toray Science Foundation; the US Department of Energy (USDOE) through the Los Alamos National Laboratory (operated by Triad National Security, LLC, for the National Nuclear Security Administration of the USDOE (Contract 89233218CNA000001)); the Italian Ministero dell'Istruzione Universita e Ricerca through the grant Progetti Premiali 2012-iALMA (CUP C52I13000140001); the European Union's Horizon 2020 research and innovation programme under grant agreement No 730562 RadioNet; ALMA North America Development Fund; the Academia Sinica; Chandra TM6-17006X; the GenT Program (Generalitat Valenciana) Project CIDEGENT/2018/021. This work used the Extreme Science and Engineering Discovery Environment (XSEDE), supported by NSF grant ACI-1548562, and CyVerse, supported by NSF grants DBI-0735191, DBI-1265383, and DBI1743442. XSEDE Stampede2 resource at TACC was allocated through TGAST170024 and TG-AST080026N. XSEDE JetStream resource at PTI and TACC was allocated through AST170028. The simulations were performed in part on the SuperMUC cluster at the LRZ in Garching, on the LOEWE cluster in CSC in Frankfurt, and on the HazelHen cluster at the HLRS in Stuttgart. This research was enabled in part by support provided by Compute Ontario (http://computeontario. r ca), Calcul Quebec (http://www.calculquebec.ca) and Compute Canada (http://www.computecanada.ca).We thank the sta ff at the participating observatories, correlation centers, and institutions for their enthusiastic support. This paper makes use of the following ALMA data: ADS/JAO.ALMA#2016.1.01154.V, ADS/JAO.ALMA#2016.1.01176.V. ALMA is a partnership of the European Southern Observatory (ESO; Europe, representing its member states), NSF, and National Institutes of Natural Sciences of Japan, together with National Research Council (Canada), Ministry of Science and Technology (MOST; Taiwan), Academia Sinica Institute of Astronomy and Astrophysics (ASIAA; Taiwan), and Korea Astronomy and Space Science Institute (KASI; Republic of Korea), in cooperation with the Republic of Chile. The Joint ALMA Observatory is operated by ESO, Associated Universities, Inc. (AUI)/NRAO, and the National Astronomical Observatory of Japan (NAOJ). The NRAO is a facility of the NSF operated under cooperative agreement by AUI. APEX is a collaboration between the Max-Planck-Institut fur Radioastronomie (Germany), ESO, and the Onsala Space Observatory (Sweden). The SMA is a joint project between the SAO and ASIAA and is funded by the Smithsonian Institution and the Academia Sinica. The JCMT is operated by the East Asian Observatory on behalf of the NAOJ, ASIAA, and KASI, as well as the Ministry of Finance of China, Chinese Academy of Sciences, and the National Key R&D Program (No. 2017YFA0402700) of China. Additional funding support for the JCMT is provided by the Science and Technologies Facility Council (UK) and participating universities in the UK and Canada. The LMT is a project operated by the Instituto Nacional de Astrofisica, Optica, y Electronica (Mexico) and the University of Massachusetts at Amherst (USA). The IRAM 30-m telescope on Pico Veleta, Spain is operated by IRAM and supported by CNRS (Centre National de la Recherche Scientifique, France), MPG (Max-Planck-Gesellschaft, Germany) and IGN (Instituto Geografico Nacional, Spain). The SMT is operated by the Arizona Radio Observatory, a part of the Steward Observatory of the University of Arizona, with financial support of operations from the State of Arizona and financial support for instrumentation development from the NSF. The SPT is supported by the National Science Foundation through grant PLR1248097. Partial support is also provided by the NSF Physics Frontier Center grant PHY-1125897 to the Kavli Institute of Cosmological Physics at the University of Chicago, the Kavli Foundation and the Gordon and Betty Moore Foundation grant GBMF 947. The SPT hydrogen maser was provided on loan from the GLT, courtesy of ASIAA. The EHTC has received generous donations of FPGA chips from Xilinx Inc., under the Xilinx University Program. The EHTC has benefited from technology shared under open-source license by the Collaboration for Astronomy Signal Processing and Electronics Research (CASPER). The EHT project is grateful to T4Science and Microsemi for their assistance with Hydrogen Masers. This research has made use of NASA's Astrophysics Data System. We gratefully acknowledge the support provided by the extended sta ff of the ALMA, both from the inception of the ALMA Phasing Project through the observational campaigns of 2017 and 2018. We would like to thank A. Deller and W. Brisken for EHT-specific support with the use of DiFX. We acknowledge the significance that Maunakea, where the SMA and JCMT EHT stations are located, has for the indigenous Hawaiian people. r This research has made use of data obtained with the Global Millimeter VLBI Array (GMVA), which consists of telescopes operated by the MPIfR, IRAM, Onsala, Metsahovi, Yebes, the Korean VLBI Network, the Green Bank Observatory and the Very Long Baseline Array (VLBA). The VLBA is an instrument of the National Radio Astronomy Observatory. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated by Associated Universities, Inc. The data were correlated at the correlator of the MPIfR in Bonn, Germany. This study makes use of 43 GHz VLBA data from the VLBA-BU Blazar Monitoring Program (VLBABU-BLAZAR; http://www.bu.edu/blazars/VLBAproject.html), funded by NASA through the Fermi Guest Investigator Program.
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- 2020
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9. Unravelling the origin of extended radio emission in narrow-line Seyfert 1 galaxies with the JVLA
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Marco Berton, Enrico Congiu, Rohan Dahale, Robert Antonucci, L. Crepaldi, and Emilia Järvelä
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Physics ,Spectral index ,Active galactic nucleus ,Star formation ,Astrophysics::High Energy Astrophysical Phenomena ,Spatially resolved ,FOS: Physical sciences ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Astrophysics - Astrophysics of Galaxies ,Galaxy ,Astrophysical jet ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,Astrophysics::Galaxy Astrophysics ,Line (formation) - Abstract
Narrow-line Seyfert 1 (NLS1) galaxies are believed to be active galactic nuclei (AGN) in the early stages of their evolution. Some dozens of them have been found to host relativistic jets, whilst the majority has not even been detected in radio, emphasising the heterogeneity of the class in this band. In this paper, our aim is to determine the predominant source of radio emission in a sample of 44 NLS1s, selected based on their extended kpc-scale radio morphologies at 5.2 GHz. We accomplish this by analysing their spatially resolved radio spectral index maps, centred at 5.2 GHz. In addition, we utilise several diagnostics based on mid-infrared emission to estimate the star formation activity of their host galaxies. These data are complemented by archival data to draw a more complete picture of each source. We find an extraordinary diversity among our sample. Approximately equal fractions of our sources can be identified as AGN-dominated, composite, and host-dominated. Among the AGN-dominated sources are a few NLS1s with very extended jets, reaching distances of tens of kpc from the nucleus. One of these, J0814+5609, hosts the most extended jets found in an NLS1 so far. We also identify five NLS1s that could be classified as compact steep-spectrum sources. We further conclude that due to the variety seen in NLS1s simple proxies, such as the star formation diagnostics also employed in this paper, and the radio loudness parameter, are not ideal tools for characterising NLS1s. We emphasise the necessity of examining NLS1s as individuals, instead of making assumptions based on their classification. When these issues are properly taken into account, NLS1s offer an exceptional environment to study the interplay of the host galaxy and several AGN-related phenomena, such as jets and outflows. [Abstract abridged.], 83 pages, 51 figures, accepted for publication in Astronomy & Astrophysics
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- 2022
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10. Coupling between turbulence and solar-like oscillations: A combined Lagrangian PDF/SPH approach
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Kevin Belkacem, M.-J. Goupil, J. Philidet, 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)
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FOS: Physical sciences ,Probability density function ,Astrophysics ,01 natural sciences ,methods: analytical ,010305 fluids & plasmas ,Physics::Fluid Dynamics ,Smoothed-particle hydrodynamics ,Stochastic differential equation ,symbols.namesake ,0103 physical sciences ,010303 astronomy & astrophysics ,Solar and Stellar Astrophysics (astro-ph.SR) ,Physics ,Turbulence ,turbulence ,Mathematical analysis ,Fluid Dynamics (physics.flu-dyn) ,Time evolution ,stars: solar-type ,Astronomy and Astrophysics ,Eulerian path ,Physics - Fluid Dynamics ,Acoustic wave ,Wave equation ,Astrophysics - Solar and Stellar Astrophysics ,Space and Planetary Science ,symbols ,stars: oscillations ,[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph] - Abstract
Aims. This series of papers aims at building a new formalism specifically tailored to study the impact of turbulence on the global modes of oscillation in solar-like stars. This first paper aims at deriving a linear wave equation that directly and consistently contains the turbulence as an input to the model, and therefore naturally contains the information on the coupling between the turbulence and the modes, through the stochasticity of the equations. Methods. We use a Lagrangian stochastic model of turbulence based on Probability Density Function methods to describe the evolution of the properties of individual fluid particles through stochastic differential equations. We then transcribe these stochastic differential equations from a Lagrangian frame to an Eulerian frame, more adapted to the analysis of stellar oscillations. We combine this method with Smoothed Particle Hydrodynamics, where all the mean fields appearing in the Lagrangian stochastic model are estimated directly from the set of fluid particles themselves, through the use of a weighting kernel function allowing to filter the particles present in any given vicinity. The resulting stochastic differential equations on Eulerian variables are then linearised. Results. We obtain a stochastic, linear wave equation governing the time evolution of the relevant wave variables, while at the same time containing the effect of turbulence. The wave equation generalises the classical, unperturbed propagation of acoustic waves in a stratified medium to a form that, by construction, accounts for the impact of turbulence on the mode in a consistent way. The effect of turbulence consists in a non-homogeneous forcing term, responsible for the stochastic driving of the mode, and a stochastic perturbation to the homogeneous part of the wave equation, responsible for both the damping of the mode and the modal surface effects., Paper accepted for publication in A&A. 18 pages (12 without Appendices), 1 figure. Typos corrected
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- 2021
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11. Energetic ions in the Venusian system: Insights from the first Solar Orbiter flyby
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R. C. Allen, I. Cernuda, D. Pacheco, L. Berger, Z. G. Xu, J. L. Freiherr von Forstner, J. Rodríguez-Pacheco, R. F. Wimmer-Schweingruber, G. C. Ho, G. M. Mason, S. K. Vines, Y. Khotyaintsev, T. Horbury, M. Maksimovic, L. Z. Hadid, M. Volwerk, A. P. Dimmock, L. Sorriso-Valvo, K. Stergiopoulou, G. B. Andrews, V. Angelini, S. D. Bale, S. Boden, S. I. Böttcher, T. Chust, S. Eldrum, P. P. Espada, F. Espinosa Lara, V. Evans, R. Gómez-Herrero, J. R. Hayes, A. M. Hellín, A. Kollhoff, V. Krasnoselskikh, M. Kretzschmar, P. Kühl, S. R. Kulkarni, W. J. Lees, E. Lorfèvre, C. Martin, H. O’Brien, D. Plettemeier, O. R. Polo, M. Prieto, A. Ravanbakhsh, S. Sánchez-Prieto, C. E. Schlemm, H. Seifert, J. Souček, M. Steller, Š. Štverák, J. C. Terasa, P. Trávníček, K. Tyagi, A. Vaivads, A. Vecchio, and M. Yedla
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Physics ,planets and satellites ,Astronomy ,turbulence ,Astronomy and Astrophysics ,Astrophysics ,Fusion, Plasma and Space Physics ,Astrobiology ,Ion ,law.invention ,planets and satellites: terrestrial planets ,Fusion, plasma och rymdfysik ,Orbiter ,Astronomi, astrofysik och kosmologi ,Space and Planetary Science ,law ,Physics::Space Physics ,planet-star interactions ,terrestrial planets ,Astronomy, Astrophysics and Cosmology ,waves ,Astrophysics::Earth and Planetary Astrophysics ,planetary systems ,acceleration of particles - Abstract
The Solar Orbiter flyby of Venus on 27 December 2020 allowed for an opportunity to measure the suprathermal to energetic ions in the Venusian system over a large range of radial distances to better understand the acceleration processes within the system and provide a characterization of galactic cosmic rays near the planet. Bursty suprathermal ion enhancements (up to ∼10 keV) were observed as far as ∼50RVdowntail. These enhancements are likely related to a combination of acceleration mechanisms in regions of strong turbulence, current sheet crossings, and boundary layer crossings, with a possible instance of ion heating due to ion cyclotron waves within the Venusian tail. Upstream of the planet, suprathermal ions are observed that might be related to pick-up acceleration of photoionized exospheric populations as far as 5RVupstream in the solar wind as has been observed before by missions such as Pioneer Venus Orbiter and Venus Express. Near the closest approach of Solar Orbiter, the Galactic cosmic ray (GCR) count rate was observed to decrease by approximately 5 percent, which is consistent with the amount of sky obscured by the planet, suggesting a negligible abundance of GCR albedo particles at over 2RV. Along with modulation of the GCR population very close to Venus, the Solar Orbiter observations show that the Venusian system, even far from the planet, can be an effective accelerator of ions up to ∼30 keV. This paper is part of a series of the first papers from the Solar Orbiter Venus flyby.
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- 2021
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12. The Galaxy Activity, Torus, and Outflow Survey (GATOS)
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Leonard Burtscher, Santiago García-Burillo, A. Alonso-Herrero, Andrew Bunker, David J. Rosario, P. G. Boorman, Chris Packham, Dimitra Rigopoulou, Miguel Pereira-Santaella, Begoña García-Lorenzo, L. K. Hunt, Francoise Combes, C. Ramos Almeida, Patrick F. Roche, Kohei Ichikawa, Takuma Izumi, Alvaro Labiano, T. Taro Shimizu, N. A. Levenson, Tanio Díaz-Santos, Claudio Ricci, David Williamson, Omaira González-Martín, Masatoshi Imanishi, Marko Stalevski, E. Lopez-Rodriguez, Poshak Gandhi, I. García-Bernete, E. K. S. Hicks, D. Rouan, Koji Wada, Sebastian F. Hönig, and Ric Davies
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INFRARED-SPECTRA ,GALACTIC NUCLEI ,Galaxies: Seyfert ,Active galactic nucleus ,Astrophysics::High Energy Astrophysical Phenomena ,Continuum (design consultancy) ,FOS: Physical sciences ,galaxies [submillimeter] ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,galaxies [infrared] ,01 natural sciences ,Submillimeter Array ,STAR-FORMATION ,Seyfert [galaxies] ,RADIATION-PRESSURE ,0103 physical sciences ,Radiative transfer ,Astrophysics::Solar and Stellar Astrophysics ,SPACE-TELESCOPE ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics ,Line (formation) ,Physics ,Luminous infrared galaxy ,ISM [galaxies] ,OBSCURING TORI ,MOLECULAR TORI ,010308 nuclear & particles physics ,Submillimeter: Galaxies ,Astronomy and Astrophysics ,Torus ,Astrophysics - Astrophysics of Galaxies ,Galaxy ,Infrared: Galaxies ,Galaxies: ISM ,NARROW-LINE REGION ,Physics and Astronomy ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,Astrophysics::Earth and Planetary Astrophysics ,SUBARCSECOND MIDINFRARED VIEW ,CLUMPY TORUS - Abstract
We compare mid-IR and ALMA far-IR images of 12 nearby Seyferts selected from GATOS. The mid-IR unresolved emission contributes more than 60% of the nuclear emission in most galaxies. By contrast, the ALMA 870micron continuum emission is mostly resolved and typically along the torus equatorial direction (Paper I, Garcia-Burillo et al. 2021). The Eddington ratios and nuclear hydrogen column densities NH of half the sample are favorable to launching polar and/or equatorial dusty winds, according to simulations. Six show mid-IR extended emission in the polar direction as traced by the NLR and perpendicular to the ALMA emission. In a few, the nuclear NH might be too high to uplift large quantities of dusty material along the polar direction. Five galaxies have low NH and/or Eddington ratios and thus polar dusty winds are not likely. We generate new CAT3D-WIND disk-wind model images. At low wind-to-disk cloud ratios the far-IR model images have disk- and ring-like morphologies. The X-shape associated with dusty winds is seen better in the far-IR at intermediate-high inclinations for the extended-wind configurations. In most models, the mid-IR emission comes from the inner part of the disk/cone. Extended bi-conical and one-sided polar mid-IR emission is seen in extended-wind configurations and high wind-to-disk cloud ratios. When convolved to our resolution, the model images reproduce qualitative aspects of the observed morphologies. Low-intermediate wind-to-disk ratios are required to account for the large fractions of unresolved mid-IR emission. This work and Paper I provide observational support for the torus+wind scenario. The wind component is more relevant at high Eddington ratios and/or AGN luminosities, and polar dust emission is predicted at NH of up to $10^{24}$cm$^{-2}$. The torus/disk component, on the other hand, prevails at low luminosities and/or Eddington ratios. (Abridged), 27 pages, 27 figures. Accepted for publication in A&A
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- 2021
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13. CAPOS: The bulge Cluster APOgee Survey
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Verne V. Smith, Antonela Monachesi, D. A. García-Hernández, Jennifer Sobeck, Rebecca Lane, S. Meszaros, Roger E. Cohen, J. G. Fernandez-Trincado, Nicolas F. Martin, Felipe Gran, Baitian Tang, Henrik Jönsson, Ricardo R. Muñoz, Beatriz Barbuy, Else Starkenburg, Doug Geisler, Lorenzo Monaco, F. Mauro, Márcio Catelan, D. González-Díaz, Joel R. Brownstein, K. M. Cunha, J. E. O'Connell, Sandro Villanova, A. Rojas-Arriagada, C. E. Ferreira Lopes, C. Muñoz, Lady Henao, Y. Reinarz, Dante Minniti, R. Contreras Ramos, Cristián E. Cortés, Javier Alonso-García, Danny Horta, C. Moni Bidin, S. R. Majewski, Manuela Zoccali, T. A. Santander, Timothy C. Beers, Celeste Parisi, A. Arentsen, R. E. Miranda, and Astronomy
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Physics ,stars: abundances ,010308 nuclear & particles physics ,Metallicity ,FOS: Physical sciences ,Astronomy and Astrophysics ,Context (language use) ,Astrophysics ,globular clusters: general ,Astrophysics - Astrophysics of Galaxies ,01 natural sciences ,Galaxy: bulge ,Radial velocity ,Stars ,Space and Planetary Science ,Bulge ,Astrophysics of Galaxies (astro-ph.GA) ,Globular cluster ,0103 physical sciences ,Cluster (physics) ,010303 astronomy & astrophysics - Abstract
Context. Bulge globular clusters (BGCs) are exceptional tracers of the formation and chemodynamical evolution of this oldest Galactic component. However, until now, observational difficulties have prevented us from taking full advantage of these powerful Galactic archeological tools. Aims. CAPOS, the bulge Cluster APOgee Survey, addresses this key topic by observing a large number of BGCs, most of which have only been poorly studied previously. Even their most basic parameters, such as metallicity, [{\alpha}/Fe], and radial velocity, are generally very uncertain. We aim to obtain accurate mean values for these parameters, as well as abundances for a number of other elements, and explore multiple populations. In this first paper, we describe the CAPOS project and present initial results for seven BGCs. Methods. CAPOS uses the APOGEE-2S spectrograph observing in the H band to penetrate obscuring dust toward the bulge. For this initial paper, we use abundances derived from ASPCAP, the APOGEE pipeline. Results. We derive mean [Fe/H] values of $-$0.85$\pm$0.04 (Terzan 2), $-$1.40$\pm$0.05 (Terzan 4), $-$1.20$\pm$0.10 (HP 1), $-$1.40$\pm$0.07 (Terzan 9), $-$1.07$\pm$0.09 (Djorg 2), $-$1.06$\pm$0.06 (NGC 6540), and $-$1.11$\pm$0.04 (NGC 6642) from three to ten stars per cluster. We determine mean abundances for eleven other elements plus the mean [$\alpha$/Fe] and radial velocity. CAPOS clusters significantly increase the sample of well-studied Main Bulge globular clusters (GCs) and also extend them to lower metallicity. We reinforce the finding that Main Bulge and Main Disk GCs, formed in situ, have [Si/Fe] abundances slightly higher than their accreted counterparts at the same metallicity. We investigate multiple populations and find our clusters generally follow the light-element (anti)correlation trends of previous studies of GCs of similar metallicity. We finally explore the abundances ..., Comment: 27 pages, 10 figures, 5 tables. Abridged abstract. Accepted for publication in Astronomy & Astrophysics (A&A)
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- 2021
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14. Temporal evolution of small-scale internetwork magnetic fields in the solar photosphere (Corrigendum)
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R. J. Campbell, Michail Mathioudakis, Manuel Collados, Chris J. Nelson, David Kuridze, Aaron Reid, A. Asensio Ramos, and P. H. Keys
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Physics ,Photosphere ,Line-of-sight ,Space and Planetary Science ,Astronomy and Astrophysics ,Geometry ,Scale (descriptive set theory) ,Astrophysics ,Table (information) ,Column (database) ,Row ,Typographical error ,Magnetic field - Abstract
We correct a typographical error in the original paper. Figures 10, 12, 14, 15, and 16 contain a table in the top right panel with four columns and four rows of values. The line of sight velocity, vLOS, values for scheme 1 inversions (in the fourth row, first column and second column) are inserted the wrong way around. The values themselves are correct, but printed in the wrong column. All other values in the tables remain unaffected, and none of the paper's discussions or conclusions are impacted. We provide corrected versions of Figs. 10, 12, 14, 15, and 16 in Figs. 1, 2, 3, 4, and 5, respectively.
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- 2021
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15. ALMA 870 μm continuum observations of HD 100546
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Claudia Toci, Davide Fedele, Luke T. Maud, and Giuseppe Lodato
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Physics ,Spiral galaxy ,media_common.quotation_subject ,Image (category theory) ,Giant planet ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,01 natural sciences ,Orbit ,Astrophysics - Solar and Stellar Astrophysics ,Space and Planetary Science ,Planet ,0103 physical sciences ,Astrophysics::Earth and Planetary Astrophysics ,Continuum (set theory) ,Eccentricity (behavior) ,010306 general physics ,Protoplanet ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics ,Astrophysics - Earth and Planetary Astrophysics ,media_common - Abstract
This paper reports on a new analysis of archival ALMA $870\,\mu$m dust continuum observations. Along with the previously observed bright inner ring ($r \sim 20-40\,$au), two addition substructures are evident in the new continuum image: a wide dust gap, $r \sim 40-150\,$au, and a faint outer ring ranging from $r \sim 150\,$au to $r \sim 250\,$au and whose presence was formerly postulated in low-angular-resolution ALMA cycle 0 observations but never before observed. Notably, the dust emission of the outer ring is not homogeneous, and it shows two prominent azimuthal asymmetries that resemble an eccentric ring with eccentricity $e = 0.07 $. The characteristic double-ring dust structure of HD 100546 is likely produced by the interaction of the disk with multiple giant protoplanets. This paper includes new smoothed-particle-hydrodynamic simulations with two giant protoplanets, one inside of the inner dust cavity and one in the dust gap. The simulations qualitatively reproduce the observations, and the final masses and orbital distances of the two planets in the simulations are 3.1 $M_{J}$ at 15 au and 8.5 $M_{J}$ at 110 au, respectively. The massive outer protoplanet substantially perturbs the disk surface density distribution and gas dynamics, producing multiple spiral arms both inward and outward of its orbit. This can explain the observed perturbed gas dynamics inward of 100 au as revealed by ALMA observations of CO. Finally, the reduced dust surface density in the $\sim 40-150\,$au dust gap can nicely clarify the origin of the previously detected H$_2$O gas and ice emission., Comment: Accepted for publication
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- 2021
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16. Variable stars in the VVV globular clusters
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Julio A. Carballo-Bello, Karla Peña Ramírez, Jura Borissova, Maren Hempel, Dante Minniti, Rodrigo Contreras Ramos, Zhen Guo, José G. Fernández-Trincado, Doug Geisler, Tali Palma, Eamonn Kerins, R. K. Saito, Felipe Gran, Leigh C. Smith, Javier Alonso-García, E. R. Garro, Márcio Catelan, Carlos E. Ferreira Lopes, Sebastián Ramírez Alegría, Philip W. Lucas, and Camila Navarrete
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media_common.quotation_subject ,Milky Way ,FOS: Physical sciences ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,variables: RR Lyrae [Stars] ,RR Lyrae variable ,01 natural sciences ,variables: general [Stars] ,0103 physical sciences ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics ,Solar and Stellar Astrophysics (astro-ph.SR) ,media_common ,Physics ,Extinction ,010308 nuclear & particles physics ,Astronomy and Astrophysics ,Astrophysics - Astrophysics of Galaxies ,Photometry (astronomy) ,Variable (computer science) ,Astrophysics - Solar and Stellar Astrophysics ,Space and Planetary Science ,Sky ,Astrophysics of Galaxies (astro-ph.GA) ,Globular cluster ,general [Globular clusters] ,Variable star - Abstract
The Galactic globular clusters (GGCs) located in the inner regions of the Milky Way suffer from high extinction that makes their observation challenging. The VVV survey provides a way to explore these GGCs in the near-infrared where extinction effects are highly diminished. We conduct a search for variable stars in several inner GGCs, taking advantage of the unique multi-epoch, wide-field, near-infrared photometry provided by the VVV survey. We are especially interested in detecting classical pulsators that will help us constrain the physical parameters of these GGCs. In this paper, the second of a series, we focus on NGC6656 (M22), NGC6626 (M28), NGC6569, and NGC6441; these four massive GGCs have known variable sources, but quite different metallicities. We also revisit 2MASS-GC02 and Terzan10, the two GGCs studied in the first paper of this series. We present an improved method and a new parameter that efficiently identify variable candidates in the GGCs. We also use the proper motions of those detected variable candidates and their positions in the sky and in the color-magnitude diagrams to assign membership to the GGCs. We identify and parametrize in the near-infrared numerous variable sources in the studied GGCs, cataloging tens of previously undetected variable stars. We recover many known classical pulsators in these clusters, including the vast majority of their fundamental mode RR Lyrae. We use these pulsators to obtain distances and extinctions toward these objects. Recalibrated period-luminosity-metallicity relations for the RR Lyrae bring the distances to these GGCs to a closer agreement with those reported by Gaia, except for NGC6441. Recovered proper motions for these GGCs also agree with those reported by Gaia, except for 2MASS-GC02, the most reddened GGC in our sample, where the VVV near-infrared measurements provide a more accurate determination of its proper motions., Comment: Accepted for publication in A&A, 18 pages, 14 Figures, 9 Tables
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- 2021
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17. The volumetric star formation law in the Milky Way
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Carlo Nipoti, Filippo Fraternali, G. Iorio, Gabriele Pezzulli, Antonino Marasco, Cecilia Bacchini, Bacchini, C., Fraternali, F., Pezzulli, G., Marasco, A., Iorio, G., Nipoti, C., and Astronomy
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DISC GALAXIES ,CHEMICAL EVOLUTION ,Astrophysics ,01 natural sciences ,law.invention ,star ,FORMATION THRESHOLDS ,galaxies ,010303 astronomy & astrophysics ,Galaxy: structure ,Physics ,formation ,disk ,ISM: structure ,Galaxies: star formation ,Galaxy: disk [Stars] ,Scale height ,MOLECULAR GAS ,Astrophysics::Earth and Planetary Astrophysics ,RADIAL-DISTRIBUTION ,stars ,SCHMIDT-LAW ,Milky Way ,Stars: formation ,FOS: Physical sciences ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Disc galaxy ,star formation ,Galaxy: disk ,3-DIMENSIONAL DISTRIBUTION ,0103 physical sciences ,Galaxy formation and evolution ,DARK-MATTER ,NEARBY GALAXIES ,structure ,Disc ,Astrophysics::Galaxy Astrophysics ,ISM ,010308 nuclear & particles physics ,Star formation ,galaxie ,Astronomy and Astrophysics ,Astrophysics - Astrophysics of Galaxies ,Galaxy ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,Law ,Hydrostatic equilibrium ,H-I - Abstract
Several open questions on galaxy formation and evolution have their roots in the lack of a universal star formation law, that could univocally link the gas properties, e.g. its density, to the star formation rate (SFR) density. In a recent paper, we used a sample of nearby disc galaxies to infer the volumetric star formation (VSF) law, a tight correlation between the gas and the SFR volume densities derived under the assumption of hydrostatic equilibrium for the gas disc. However, due to the dearth of information about the vertical distribution of the SFR in these galaxies, we could not find a unique slope for the VSF law, but two alternative values. In this paper, we use the scale height of the SFR density distribution in our Galaxy adopting classical Cepheids (age$\lesssim 200$ Myr) as tracers of star formation. We show that this latter is fully compatible with the flaring scale height expected from gas in hydrostatic equilibrium. These scale heights allowed us to convert the observed surface densities of gas and SFR into the corresponding volume densities. Our results indicate that the VSF law $\rho_\mathrm{SFR} \propto \rho_\mathrm{gas}^\alpha$ with $\alpha \approx 2$ is valid in the Milky Way as well as in nearby disc galaxies., Comment: 9 pages, 4 figures, + 4 pages of Appendix, accepted by A&A
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- 2019
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18. KiDS-SQuaD II. Machine learning selection of bright extragalactic objects to search for new gravitationally lensed quasars
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Fedor Getman, Chiara Spiniello, Vladislav Khramtsov, Alexey V. Sergeyev, Adriano Agnello, Valery Shulga, Konrad Kuijken, Crescenzo Tortora, Mario Radovich, Jelte T. A. de Jong, Nicola R. Napolitano, Huanyuan Shan, and Astronomy
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Dark matter ,FOS: Physical sciences ,GAIA ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Machine learning ,computer.software_genre ,01 natural sciences ,CLASSIFICATION ,Gravitation ,surveys ,quasars: general ,0103 physical sciences ,data analysis [methods] ,DARK-MATTER ,EARLY-TYPE GALAXIES ,FIELD ,Instrumentation and Methods for Astrophysics (astro-ph.IM) ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics ,Physics ,general [quasars] ,010308 nuclear & particles physics ,business.industry ,Astrophysics::Instrumentation and Methods for Astrophysics ,KILO-DEGREE SURVEY ,CANDIDATE ,gravitational lensing: strong ,Astronomy and Astrophysics ,Quasar ,Astrophysics - Astrophysics of Galaxies ,methods: data analysis ,galaxies: general ,CATALOG ,Galaxy ,EVOLUTION ,Stars ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,strong [gravitational lensing] ,DISCOVERY ,Artificial intelligence ,Astrophysics - Instrumentation and Methods for Astrophysics ,business ,Data release ,computer ,Classifier (UML) ,catalogs ,general [galaxies] - Abstract
The KiDS Strongly lensed QUAsar Detection project (KiDS-SQuaD) aims at finding as many previously undiscovered gravitational lensed quasars as possible in the Kilo Degree Survey. This is the second paper of this series where we present a new, automatic object classification method based on machine learning technique. The main goal of this paper is to build a catalogue of bright extragalactic objects (galaxies and quasars), from the KiDS Data Release 4, with a minimum stellar contamination, preserving the completeness as much as possible, to then apply morphological methods to select reliable gravitationally lensed (GL) quasar candidates. After testing some of the most used machine learning algorithms, decision trees based classifiers, we decided to use CatBoost, that was specifically trained with the aim of creating a sample of extragalactic sources as clean as possible from stars. We discuss the input data, define the training sample for the classifier, give quantitative estimates of its performances, and finally describe the validation results with Gaia DR2, AllWISE, and GAMA catalogues. We have built and make available to the scientific community the KiDS Bright EXtraGalactic Objects catalogue (KiDS-BEXGO), specifically created to find gravitational lenses. This is made of $\approx6$ millions of sources classified as quasars ($\approx 200\,000$) and galaxies ($\approx 5.7$M), up to $r, Submitted to Astronomy and Astrophysics, 19 pages, 12 figures, 4 tables
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- 2019
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19. The Fornax Deep Survey with the VST. V. Exploring the faintest regions of the bright early-type galaxies inside the virial radius
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G. van de Ven, Pietro Schipani, Enrica Iodice, Maurizio Paolillo, M. Capaccioli, Anna Pasquali, Jesús Falcón-Barroso, Aku Venhola, R. D'Abrusco, M. Cantiello, A. Grado, L. Limatola, Marilena Spavone, Nicola R. Napolitano, Reynier Peletier, S. Mieske, Michael Hilker, Rory Smith, Iodice, E., Spavone, M., Capaccioli, M., Peletier, R. ~F., van de Ven, G., Napolitano, N. ~R., Hilker, M., Mieske, S., Smith, R., Pasquali, A., Limatola, L., Grado, A., Venhola, A., Cantiello, M., Paolillo, M., Falcon-Barroso, J., D'Abrusco, R., Schipani, P., and Astronomy
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DWARF GALAXIES ,Stellar population ,TIDAL STREAMS ,FOS: Physical sciences ,Context (language use) ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,01 natural sciences ,cD ,STAR-FORMATION ,surveys ,GLOBULAR-CLUSTERS ,0103 physical sciences ,Astrophysics::Solar and Stellar Astrophysics ,INTRACLUSTER LIGHT ,Surface brightness ,QUANTITATIVE MORPHOLOGY ,Fornax Cluster ,galaxies: elliptical and lenticular ,individual ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics ,Physics ,010308 nuclear & particles physics ,galaxies: clusters: individual: Fornax ,Astronomy and Astrophysics ,Radius ,Position angle ,VIRGO CLUSTER ,Astrophysics - Astrophysics of Galaxies ,Galaxy ,KINEMATICALLY DISTINCT CORES ,galaxies: photometry ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,Globular cluster ,Fornax ,SPIRAL GALAXIES ,MORPHOLOGY-DENSITY RELATION - Abstract
This paper is based on the multi-band (ugri) Fornax Deep Survey (FDS) with the VLT Survey Telescope (VST). We study bright early-type galaxies (m_B 28 mag/arcsec^2). Therefore, the new FDS data allow us to explore in great detail the morphology and structure of cluster galaxies out to the region of the stellar halo. The observations suggest that the Fornax cluster is not completely relaxed inside the virial radius. The bulk of the gravitational interactions between galaxies happens in the W-NW core region of the cluster, where most of the bright early-type galaxies are located and where the intra-cluster baryons (diffuse light and GCs) are found. We suggest that the W-NW sub-clump of galaxies results from an infalling group onto the cluster, which has modified the structure of the galaxy outskirts (making asymmetric stellar halos) and has produced the intra-cluster baryons (ICL and GCs), concentrated in this region of the cluster., Accepted for publication in Astronomy & Astrophysics. High-resolution version of paper is available at the following link: https://www.dropbox.com/s/ybe4tg2hbqayteh/FDS_V.ETGs.pdf?dl=0
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- 2019
20. Magnetized relativistic jets and helical magnetic fields
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José L. Gómez, A. Fuentes, I. Moya-Torregrosa, José-María Martí, Manel Perucho, Ministerio de Economía y Competitividad (España), Ministerio de Ciencia, Innovación y Universidades (España), Generalitat Valenciana, Junta de Andalucía, European Commission, and Consejo Superior de Investigaciones Científicas (España)
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Magnetohydrodynamics (MHD) ,Astrophysics::High Energy Astrophysical Phenomena ,Astrophysics ,01 natural sciences ,symbols.namesake ,Astrophysical jet ,analytical [Methods] ,0103 physical sciences ,Methods: analytical ,010303 astronomy & astrophysics ,Physics ,Jet (fluid) ,numerical [Methods] ,Toroid ,Methods: numerical ,010308 nuclear & particles physics ,Astronomy and Astrophysics ,Computational physics ,Magnetic field ,Amplitude ,Mach number ,Galaxies: jets ,Space and Planetary Science ,Magnetic fields ,symbols ,Oblique shock ,jets [Galaxies] ,Lorentz force - Abstract
This is the first of a series of two papers that deepen our understanding of the transversal structure and the properties of recollimation shocks of axisymmetric, relativistic, superfast magnetosonic, overpressured jets. They extend previous work that characterized these properties in connection with the dominant type of energy (internal, kinetic, or magnetic) in the jet to models with helical magnetic fields with larger magnetic pitch angles and force-free magnetic fields. In this paper, the magnetohydrodynamical models were computed following an approach that allows studying the structure of steady, axisymmetric, relativistic (magnetized) flows using one-dimensional time-dependent simulations. In these approaches, the relevance of the magnetic tension and of the Lorentz force in shaping the internal structure of jets (transversal structure, radial oscillations, and internal shocks) is discussed. The radial Lorentz force controls the jet internal transversal equilibrium. Hence, highly magnetized non-force-free jets exhibit a thin spine of high internal energy around the axis. The properties of the recollimation shocks and sideways expansions and compressions of the jet result from the total pressure mismatch at the jet surface, which among other factors depends on the magnetic tension and the magnetosonic Mach number of the flow. Hot jets with low Mach number tend to have strong oblique shocks and wide radial oscillations. Highly magnetized jets with large toroidal fields tend to have weaker shocks and radial oscillations of smaller amplitude. In the second paper, we present synthetic synchrotron radio images of the magnetohydrodynamical models that are produced at a post-processing phase, focusing on the observational properties of the jets, namely the top-down emission asymmetries, spine brightening, the relative intensity of the knots, and polarized emission. © ESO 2021., JMM and MP acknowledge financial support from the Spanish Ministerio de Economia y Competitividad (grant AYA2016-77237-C33-P), the Spanish Ministerio de Ciencia (PID2019-107427GB-C33), and from the local Autonomous Government (Generalitat Valenciana, grant PROMETEO/2019/071). JMM acknowledges further financial support from the Spanish Ministerio de Economia y Competitividad (grant PGC2018-095984-B-I00). MP acknowledges further financial support from the Spanish Ministerio de Ciencia through grant PID2019-105510GB-C31. AF and JLG acknowledge financial support from the Spanish Ministerio de Economia y Competitividad (grants AYA2016-80889-P, PID2019-108995GB-C21), the Consejeria de Economia, Conocimiento, Empresas y Universidad of the Junta de Andalucia (grant P18-FR-1769), the Consejo Superior de Investigaciones Cientificas (grant 2019AEP112), and the State Agency for Research of the Spanish MCIU through the Center of Excellence Severo Ochoa award for the Instituto de Astrofisica de Andalucia (SEV-2017-0709). This research made use of Python (http://www.python.org), Numpy (van der Walt et al. 2011), Pandas (McKinney 2010), and Matplotlib (Hunter 2007). We also made use of Astropy (http://www.astropy.org), a community-developed core Python package for Astronomy (Astropy Collaboration 2013, 2018).
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- 2021
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21. Spatially resolved spectroscopy across stellar surfaces
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Dainis Dravins, Hans-Günter Ludwig, and Bernd Freytag
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Earth and Planetary Astrophysics (astro-ph.EP) ,Physics ,FOS: Physical sciences ,Astronomy and Astrophysics ,Context (language use) ,Astrophysics ,Stellar classification ,01 natural sciences ,Exoplanet ,Spectral line ,Stars ,Astrophysics - Solar and Stellar Astrophysics ,Space and Planetary Science ,0103 physical sciences ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,Spectral resolution ,Astrophysics - Instrumentation and Methods for Astrophysics ,010306 general physics ,Spectroscopy ,Instrumentation and Methods for Astrophysics (astro-ph.IM) ,010303 astronomy & astrophysics ,Solar and Stellar Astrophysics (astro-ph.SR) ,Astrophysics - Earth and Planetary Astrophysics ,Line (formation) - Abstract
High-precision stellar analyses require hydrodynamic 3D modeling. Such models predict changes across stellar disks of spectral line shapes, asymmetries, and wavelength shifts. For testing models in stars other than the Sun, spatially resolved observations are feasible from differential spectroscopy during exoplanet transits, retrieving spectra of stellar surface segments that successively become hidden behind the transiting planet, as shown in Papers I, II, and III. Synthetic high-resolution spectra over extended spectral regions are now available from 3D models. Similar to other ab initio simulations, these data contain patterns that have not been specifically modeled but may be revealed after analyses analogous to those of a large volume of observations. From five 3D models spanning T=3964-6726K (approx. spectral types K8V-F3V), synthetic spectra at hyper-high resolution (R>1,000,000) were analyzed. Selected FeI and FeII lines at various positions across stellar disks were searched for patterns between different lines in the same star and for similar lines between different stars. Such patterns are identified for representative photospheric lines of different strengths, excitation potential, and ionization level, encoding the hydrodynamic 3D structure. Line profiles and bisectors are shown for various stars at different positions across stellar disks. Absolute convective wavelength shifts are obtained as differences to 1D models, where such shifts do not occur. Observable relationships for line properties are retrieved from realistically complex synthetic spectra. Such patterns may also test very detailed 3D modeling, including non-LTE effects. While present results are obtained at hyper-high spectral resolution, the subsequent Paper V examines their practical observability at realistically lower resolutions, and in the presence of noise., 17 pages, 10 figures, accepted for publication in Astronomy & Astrophysics
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- 2021
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22. A super-Earth on a close-in orbit around the M1V star GJ 740
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E. González-Álvarez, Ignasi Ribas, Alessandro Sozzetti, M. Perger, B. Toledo-Padrón, Mario Damasso, Ansgar Reiners, Paolo Giacobbe, J. A. Caballero, Rafael Rebolo, A. Suárez Mascareño, Giuseppe Leto, Enrique Herrero, L. Affer, R. Zanmar Sanchez, Giuseppina Micela, Mathias Zechmeister, J. I. González Hernández, Isabella Pagano, Juan Carlos Morales, Matteo Pinamonti, Gaetano Scandariato, P. J. Amado, Jesus Maldonado, Silvano Desidera, Andreas Quirrenbach, Ministerio de Ciencia e Innovación (España), European Commission, Agenzia Spaziale Italiana, Istituto Nazionale di Astrofisica, Ministerio de Economía y Competitividad (España), German Research Foundation, and Ministero dell'Istruzione, dell'Università e della Ricerca
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Stars: activity ,NASA Exoplanet Archive ,FOS: Physical sciences ,Library science ,Instrumentation: spectrographs ,Astrophysics ,01 natural sciences ,7. Clean energy ,individual: GJ 740 [Stars] ,symbols.namesake ,Observatory ,0103 physical sciences ,Galileo (satellite navigation) ,media_common.cataloged_instance ,spectrographs [Instrumentation] ,European union ,010303 astronomy & astrophysics ,Solar and Stellar Astrophysics (astro-ph.SR) ,media_common ,Earth and Planetary Astrophysics (astro-ph.EP) ,Physics ,radial velocities [Techniques] ,010308 nuclear & particles physics ,photometric [Techniques] ,Astronomy and Astrophysics ,Planets and satellites: detection ,Stars: individual: GJ 740 ,detection [Planets and satellites] ,Astrophysics - Solar and Stellar Astrophysics ,13. Climate action ,Space and Planetary Science ,Techniques: radial velocities ,symbols ,Christian ministry ,German science ,Techniques: photometric ,activity [Stars] ,Astrophysics - Earth and Planetary Astrophysics - Abstract
Context. M-dwarfs have proven to be ideal targets for planetary radial velocity (RV) searches due to their higher planet-star mass contrast, which favors the detection of low-mass planets. The abundance of super-Earth and Earth-like planets detected around this type of star motivates further such research on hosts without reported planetary companions. Aims. The HADES and CARMENES programs are aimed at carrying out extensive searches of exoplanetary systems around M-type stars in the northern hemisphere, allowing us to address, in a statistical sense, the properties of the planets orbiting these objects. In this work, we perform a spectroscopic and photometric study of one of the program stars (GJ 740), which exhibits a short-period RV signal that is compatible with a planetary companion. Methods. We carried out a spectroscopic analysis based on 129 HARPS-N spectra taken over a time span of 6 yr combined with 57 HARPS spectra taken over 4 yr, as well as 32 CARMENES spectra taken during more than 1 yr, resulting in a dataset with a time coverage of 10 yr. We also relied on 459 measurements from the public ASAS survey with a time-coverage of 8 yr, along with 5 yr of photometric magnitudes from the EXORAP project taken in the V, B, R, and I filters to carry out a photometric study. Both analyses were made using Markov chain Monte Carlo simulations and Gaussian process regression to model the activity of the star. Results. We present the discovery of a short-period super-Earth with an orbital period of 2.37756-0.00011+0.00013 d and a minimum mass of 2.96-0.48+0.50 M . We offer an update to the previously reported characterization of the magnetic cycle and rotation period of the star, obtaining values of Prot = 35.563 ± 0.071 d and Pcycle = 2800 ± 150 d. Furthermore, the RV time series exhibits a possibly periodic long-term signal, which might be related to a Saturn-mass planet of ~100 M . © ESO 2021., B.T.P. acknowledges Fundación La Caixa for the financial support received in the form of a Ph.D. contract. A.S.M. acknowledges financial support from the Spanish Ministry of Science and Innovation (MICINN) under the 2019 Juan de la Cierva Programme. J.I.G.H. acknowledges financial support from Spanish MICINN under the 2013 Ramón y Cajal program RYC-2013-14875. B.T.P., A.S.M., J.I.G.H. and R.R. acknowledge financial support from the Spanish MICINN AYA2017-86389-P. I.R. and M.Pe. acknowledge support from the Spanish MICINN and the Fondo Europeo de Desarrollo Regional (FEDER) through grant PGC2018-098153-B-C33, as well as the support of the Generalitat de Catalunya/CERCA program. G.A.P.S. acknowledges support from INAF through the Progetti Premiali funding scheme of the Italian Ministry of Education, University, and Research. G.A.P.S. acknowledges financial support from Progetto Premiale 2015 FRONTIERA (OB.FU. 1.05.06.11) funding scheme of the Italian Ministry of Education, University, and Research. G.S. acknowledges the funding support from Italian Space Agency (ASI) regulated by “Accordo ASI-INAF n. 2013-016-R.0 del 9 luglio 2013 e integrazione del 9 luglio 2015”. This research has received financial support from the agreement ASI-INAF n.2018-16-HH.0. The results of this paper were based on observations made with the Italian Telescopio Nazionale Galileo (TNG), operated on the island of La Palma by the INAF-Fundación Galileo Galilei at the Roque de Los Muchachos Observatory of the Instituto de Astrofísica de Canarias (IAC); observations made with the HARPS instrument on the ESO 3.6-m telescope at La Silla Observatory (Chile); and observations made with the CARMENES instrument. CARMENES is an instrument for the Centro Astronómico Hispano-Alemán de Calar Alto (CAHA, Almería, Spain). CARMENES is funded by the German Max-Planck-Gesellschaft (MPG), the Spanish Consejo Superior de Investiga-ciones Científicas (CSIC), the European Union through FEDER/ERF FICTS-2011-02 funds, and the members of the CARMENES Consortium (Max-Planck-Institut für Astronomie, Instituto de Astrofísica de Andalucía, Landessternwarte Königstuhl, Institut de Ciències de l’Espai, Insitut für Astrophysik Göttingen, Universidad Complutense de Madrid, Thüringer Landessternwarte Tautenburg, Instituto de Astrofísica de Canarias, Hamburger Sternwarte, Centro de Astrobi-ología and Centro Astronómico Hispano-Alemán), with additional contributions by the Spanish MICINN through projects RYC2013-14875, AYA2015-69350-C3-2-P, AYA2016-79425-C3-1/2/3-P, ESP2016-80435-C2-1-R, ESP2017-87143-R, ESP2017-87676-C05-1/2/5-R, and AYA2017-86389-P, the German Science Foundation through the Major Research Instrumentation Program and DFG Research Unit FOR2544 “Blue Planets around Red Stars”, the Klaus Tschira Stiftung, the states of Baden-Württemberg and Niedersachsen, and by the Junta de Andalucía. This paper made use of the IAC Supercomputing facility HTCon-dor (http://research.cs.wisc.edu/htcondor/), partly financed by the MICINN with FEDER funds, code IACA13-3E-2493. This research has made use of the NASA Exoplanet Archive, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. This paper makes use of data from the first public release of the WASP data (Butters et al. 2010) as provided by the WASP consortium and services at the NASA Exoplanet Archive, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. This work has made use of data from the European Space Agency (ESA) mission Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and Analysis Consortium (DPAC, https://www. cosmos.esa.int/web/gaia/dpac/consortium). Funding for the DPAC has been provided by national institutions, in particular, the institutions participating in the Gaia Multilateral Agreement., With funding from the Spanish government through the Severo Ochoa Centre of Excellence accreditation SEV-2017-0709.
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- 2021
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23. Radio halos in a mass-selected sample of 75 galaxy clusters
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G. W. Pratt, Ruta Kale, Gianfranco Brunetti, R. J. van Weeren, Simona Giacintucci, Stefano Ettori, Daniele Dallacasa, V. Cuciti, Rossella Cassano, Annalisa Bonafede, Tiziana Venturi, F. de Gasperin, Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Cuciti V., Cassano R., Brunetti G., Dallacasa D., Van Weeren R.J., Giacintucci S., Bonafede A., De Gasperin F., Ettori S., Kale R., Pratt G.W., and Venturi T.
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Cosmology and Nongalactic Astrophysics (astro-ph.CO) ,galaxies: clusters: intracluster medium ,Astrophysics - cosmology and nongalactic astrophysics ,Astrophysics::High Energy Astrophysical Phenomena ,FOS: Physical sciences ,Context (language use) ,Sample (statistics) ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,01 natural sciences ,Jansky ,symbols.namesake ,0103 physical sciences ,Cluster (physics) ,Planck ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics ,Galaxy cluster ,Physics ,Giant Metrewave Radio Telescope ,010308 nuclear & particles physics ,Astronomy and Astrophysics ,radiation mechanisms: non-thermal ,galaxies: clusters: general ,Space and Planetary Science ,symbols ,Halo ,[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph] - Abstract
Radio halos are synchrotron diffuse sources at the centre of a fraction of galaxy clusters. The study of large samples of clusters with adequate radio and X-ray data is necessary to investigate the origin of radio halos and their connection with the cluster dynamics and formation history. The aim of this paper is to compile a well-selected sample of galaxy clusters with deep radio observations to perform an unbiased statistical study of the properties of radio halos. We selected 75 clusters with M > = 6e14 Msun at z=0.08-0.33 from the Planck Sunyaev-Zel'dovich catalogue. Clusters without suitable radio data were observed with the Giant Metrewave Radio Telescope (GMRT) and/or the Jansky Very Large Array (JVLA) to complete the information about the possible presence of diffuse emission. We used archival Chandra X-ray data to derive information on the clusters' dynamical states. This observational campaign led to the detection of several cluster-scale diffuse radio sources and candidates that deserve future follow-up observations. Here we summarise their properties and add information resulting from our new observations. For the clusters where we did not detect any hint of diffuse emission, we derived new upper limits to their diffuse flux. We have built the largest mass-selected (> 80 per cent complete in mass) sample of galaxy clusters with deep radio observations available to date. The statistical analysis of the sample, which includes the connection between radio halos and cluster mergers, the radio power-mass correlation, and the occurrence of radio halos as a function of the cluster mass, will be presented in paper II., 35 pages, 42 figures, accepted for publication in A&A
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- 2021
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24. Sensitivity of a low-frequency polarimetric radio interferometer
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Maria Kovaleva, Marcin Sokolowski, Daniel C. X. Ung, Adrian Sutinjo, Steven Tingay, J. W. Broderick, Randall B. Wayth, and David B. Davidson
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Physics ,business.industry ,Antenna aperture ,Astrophysics::Instrumentation and Methods for Astrophysics ,FOS: Physical sciences ,020206 networking & telecommunications ,Astronomy and Astrophysics ,Murchison Widefield Array ,02 engineering and technology ,Astrophysics ,01 natural sciences ,Radio telescope ,Interferometry ,Optics ,Space and Planetary Science ,0103 physical sciences ,0202 electrical engineering, electronic engineering, information engineering ,Astronomical interferometer ,Sensitivity (control systems) ,Antenna (radio) ,Astrophysics - Instrumentation and Methods for Astrophysics ,business ,Instrumentation and Methods for Astrophysics (astro-ph.IM) ,010303 astronomy & astrophysics ,Radio astronomy - Abstract
Aims: This paper aims to derive an expression for the sensitivity of a polarimetric radio interferometer that is valid for all-sky observations of arbitrarily polarized sources, with neither a restriction on FoV nor with any a priori assumption regarding the polarization state of the source. We verify the resulting formula with an all-sky observation using the Murchison Widefield Array (MWA) telescope. Methods: The sensitivity expression is developed from first principles by applying the concept of System Equivalent Flux Density (SEFD) to a polarimetric radio interferometer not by computing $A_e/T_{sys}$. The SEFD is calculated from the standard deviation of the noisy flux density estimate for a target source due to system noise. Results: The SEFD for a polarimetric radio interferometer is generally not $1/\sqrt{2}$ of a single-polarized interferometer as is often assumed for narrow FoV. This assumption can lead to significant errors for a dual-polarized dipole based system, which is common in low-frequency radio astronomy: up to $\sim 15\%$ for a zenith angle (ZA) coverage of $45^\circ$, and up to $\sim45\%$ for $60^\circ$ coverage. The worst case errors occur in the diagonal planes of the dipole for very wide FoV. This is demonstrated through theory, simulation and observations. Furthermore, using the resulting formulation, calculation of the off-zenith sensitivity is straightforward and unambiguous. Conclusions: For wide FoV observations pertinent to low-frequency radio interferometer such as the SKA-Low, the narrow FoV and the single-polarized sensitivity expressions are not correct and should be replaced by the formula derived in this paper., Comment: 12 pages, 12 figures
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- 2021
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25. VLA ammonia observations of L1287
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Inma Sepúlveda, Guillem Anglada, Robert Estalella, Angels Riera, José M. Torrelles, Aina Palau, Luis F. Rodríguez, Gemma Busquet, Rosario López, Ministerio de Ciencia, Innovación y Universidades (España), European Commission, and Consejo Nacional de Ciencia y Tecnología (México)
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Stars: formation ,Young stellar object ,FOS: Physical sciences ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Rotation ,01 natural sciences ,Spectral line ,Protein filament ,0103 physical sciences ,Cluster (physics) ,Astrophysics::Solar and Stellar Astrophysics ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics ,formation [Stars] ,ISM: general ,Physics ,general [ISM] ,010308 nuclear & particles physics ,Molecular cloud ,Astronomy and Astrophysics ,Astrophysics - Astrophysics of Galaxies ,Core (optical fiber) ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,ISM: individual objects: LDN 1287 ,Outflow ,individual objects: LDN 1287 [ISM] - Abstract
Aims. In this paper, we study the dense gas of the molecular cloud LDN 1287 (L1287), which harbors a double FU Ori system, an energetic molecular outflow, and a still-forming cluster of deeply embedded low-mass young stellar objects that show a high level of fragmentation. Methods. We present optical Hα and [SII], and VLA NH3 (1, 1) and (2, 2) observations with an angular resolution of ∼3′′.5. The observed NH3 spectra have been analyzed with the Hyperfine Structure tool, fitting simultaneously three different velocity components. Results. The NH3 emission from L1287 comes from four different structures: a core associated with RNO 1, a guitar-shaped core (the Guitar) and two interlaced filaments (the blue and red filaments) roughly centered toward the binary FU Ori system RNO 1B/1C and its associated cluster. Regarding the Guitar core, there are clear signatures of gas infall onto a central mass that has been estimated to be ∼2.1Mpdbl. Regarding the two filaments, they have radii of ∼0.03 pc, masses per unit length of ∼50Mpdbl pc-1, and are in near isothermal equilibrium. A central cavity is identified, probably related with the outflow and also revealed by the Hα and [SII] emission, with several young stellar objects near its inner walls. Both filaments show clear signs of perturbation by the high-velocity gas of the outflows driven by one or several young stellar objects of the cluster. The blue and red filaments are coherent in velocity and have nearly subsonic gas motions, except at the position of the embedded sources. Velocity gradients across the blue filament can be interpreted either as infalling material onto the filament or rotation. Velocity gradients along the filaments are interpreted as infall motions toward a gravitational well at the intersection of the two filaments. © ESO 2020., We thank Eugenio Schisano for providing us with the Herschel catalogue of the region. We thank the referee for his/her careful and helpful review of the paper. This work has been partially supported by the State Agency for Research (AEI) of the Spanish MCIU through the AYA2017-84390-C2 grant (cofunded with FEDER funds), and through the "Unit of Excellence Maria de Maeztu 2020-2023" award to the Institute of Cosmos Sciences (CEX2019-000918-M) and the 'Center of Excellence Severo Ochoa' award for the Instituto de Astrofisica de Andalucia (SEV-2017-0709). A. P. acknowledges financial support from CONACyT and UNAM-PAPIIT IN113119 grant, Mexico.
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- 2020
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26. Influences of protoplanet-induced three-dimensional gas flow on pebble accretion
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Hiroyuki Kurokawa and Ayumu Kuwahara
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Physics ,Outer planets ,Turbulence ,Astronomy and Astrophysics ,Mechanics ,Protoplanetary disk ,01 natural sciences ,Space and Planetary Science ,Planet ,Inviscid flow ,0103 physical sciences ,010306 general physics ,Pebble ,Protoplanet ,010303 astronomy & astrophysics ,Stokes number - Abstract
Context. Pebble accretion is among the major theories of planet formation. Aerodynamically small particles, called pebbles, are highly affected by the gas flow. A growing planet embedded in a protoplanetary disk induces three-dimensional (3D) gas flow. In our previous work, Paper I, we focused on the shear regime of pebble accretion and investigated the influence of planet-induced gas flow on pebble accretion. In Paper I, we found that pebble accretion is inefficient in the planet-induced gas flow compared to that of the unperturbed flow, particularly when St ≲ 10−3, where St is the Stokes number. Aims. Following on the findings of Paper I, we investigate the influence of planet-induced gas flow on pebble accretion. We did not consider the headwind of the gas in Paper I. Here, we extend our study to the headwind regime of pebble accretion. Methods. Assuming a nonisothermal, inviscid sub-Keplerian gas disk, we performed 3D hydrodynamical simulations on the spherical polar grid hosting a planet with the dimensionless mass, m = RBondi∕H, located at its center, where RBondi and H are the Bondi radius and the disk scale height, respectively. We then numerically integrated the equation of motion for pebbles in 3D using hydrodynamical simulation data. Results. We first divided the planet-induced gas flow into two regimes: flow-shear and flow-headwind. In the flow-shear regime, where the planet-induced gas flow has a vertically rotational symmetric structure, we find that the outcome is identical to what we obtained in Paper I. In the flow-headwind regime, the strong headwind of the gas breaks the symmetric structure of the planet-induced gas flow. In the flow-headwind regime, we find that the trajectories of pebbles with St ≲ 10−3 in the planet-induced gas flow differ significantly from those of the unperturbed flow. The recycling flow, where gas from the disk enters the gravitational sphere at low latitudes and exits at high latitudes, gathers pebbles around the planet. We derive the flow transition mass analytically, mt, flow, which discriminates between the flow-headwind and flow-shear regimes. From the relation between m, mt, flow and mt, peb, where mt, peb is the transition mass of the accretion regime of pebbles, we classify the results obtained in both Paper I and this study into four groups. In particular, only when the Stokes gas drag law is adopted and m < min(mt, peb, mt, flow), where the accretion and flow regime are both in the headwind regime, the accretion probability of pebbles with St ≲ 10−3 is enhanced in the planet-induced gas flow compared to that of the unperturbed flow. Conclusions. Combining our results with the spacial variety of turbulence strength and pebble size in a disk, we conclude that the planet-induced gas flow still allows for pebble accretion in the early stage of planet formation. The suppression of pebble accretion due to the planet-induced gas flow occurs only in the late stage of planet formation, more specifically, in the inner region of the disk. This may be helpful for explaining the distribution of exoplanets and the architecture of the Solar System, both of which have small inner and large outer planets.
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- 2020
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27. Voracious vortices in cataclysmic variables
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Vitaly Neustroev and Sergey Zharikov
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010504 meteorology & atmospheric sciences ,Astrophysics::High Energy Astrophysical Phenomena ,FOS: Physical sciences ,Context (language use) ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,01 natural sciences ,symbols.namesake ,0103 physical sciences ,Astrophysics::Solar and Stellar Astrophysics ,Roche lobe ,Emission spectrum ,010303 astronomy & astrophysics ,Dwarf nova ,Astrophysics::Galaxy Astrophysics ,Solar and Stellar Astrophysics (astro-ph.SR) ,0105 earth and related environmental sciences ,High Energy Astrophysical Phenomena (astro-ph.HE) ,Physics ,Accretion (meteorology) ,Balmer series ,White dwarf ,Astronomy and Astrophysics ,Radius ,Astrophysics - Solar and Stellar Astrophysics ,13. Climate action ,Space and Planetary Science ,symbols ,Astrophysics::Earth and Planetary Astrophysics ,Astrophysics - High Energy Astrophysical Phenomena - Abstract
In our earlier Paper I we showed that the accretion disc radius of the dwarf nova HT Cas in its quiescent state has not changed significantly during many years of observations. It has remained consistently large, close to the tidal truncation radius. This result is inconsistent with the modern understanding of the evolution of the disc radius through an outburst cycle. Here we present a new set of time-resolved spectra of HT Cas obtained in the middle of its 2017 superoutburst. We used Doppler tomography to map emission structures in the system, which we compared with those detected in quiescence. We used solutions of the restricted three-body problem to re-discuss the location of emission structures and the disc size of HT Cas in quiescence. The superoutburst spectrum is similar in appearance to the quiescent spectra, although the strength of most of the emission lines decreased. However, the high-excitation lines significantly strengthened in comparison with the Balmer lines. Many lines show a mix of broad emission and narrow absorption components. H$\alpha$ in superoutburst was much narrower than in quiescence. Other emission lines also narrowed in outburst, but they had not become as narrow as H$\alpha$. Doppler maps of H$\alpha$ in quiescence, and of the H$\beta$ and HeI lines in outburst are dominated by a bright emission arc in the right side of the tomograms, which is located at and even beyond the theoretical truncation limit. However, the bulk of the H$\alpha$ emission in outburst has significantly lower velocities. We show that the accretion disc radius of HT Cas during its superoutburst has become hot but remained the same size as it was in quiescence. Instead, we detected cool gas beyond the Roche lobe of the white dwarf that may have been expelled from the hot disc during the superoutburst., Comment: 14 pages, 12 figures, 2 tables. Replaced to match the version published in A&A. This is the second paper of a series of two. The first paper can be found here arXiv:1506.04753
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- 2020
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28. A physical background model for the Fermi Gamma-ray Burst Monitor
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Jochen Greiner, B. Biltzinger, J. Michael Burgess, F. Kunzweiler, and Kilian Toelge
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High Energy Astrophysical Phenomena (astro-ph.HE) ,Physics ,010504 meteorology & atmospheric sciences ,Astrophysics::High Energy Astrophysical Phenomena ,FOS: Physical sciences ,Astronomy and Astrophysics ,Astrophysics ,01 natural sciences ,ddc ,On board ,Methods statistical ,Space and Planetary Science ,Search algorithm ,0103 physical sciences ,Spectral analysis ,Satellite ,Transient (oscillation) ,Astrophysics - Instrumentation and Methods for Astrophysics ,Astrophysics - High Energy Astrophysical Phenomena ,Gamma-ray burst ,Instrumentation and Methods for Astrophysics (astro-ph.IM) ,010303 astronomy & astrophysics ,0105 earth and related environmental sciences ,Fermi Gamma-ray Space Telescope - Abstract
We present the first physically motivated background model for the Gamma-Ray Burst Monitor (GBM) onboard the Fermi satellite. Such a physically motivated background model has the potential to significantly improve the scientific output of Fermi/GBM, as it can be used to improve the background estimate for spectral analysis and localization of Gamma-Ray Bursts (GRBs) and other sources. Additionally, it can also lead to detections of new transient events, since long/weak or slowly rising ones do not activate one of the existing trigger algorithms. In this paper we show the derivation of such a physically motivated background model, which includes the modeling of the different background sources and the correct handling of the response of GBM. While the goal of the paper is to introduce the model rather than developing a transient search algorithm, we demonstrate the ability of the model to fit the background seen by GBM by showing four applications, namely (1) for a canonical GRB, (2) for the ultra-long GRB 091024, (3) for the V404 Cygni outburst in June 2015, and (4) the ultra-long GRB 130925A., Accepted for publication in A&A, 15 pages, 22 figures
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- 2020
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29. Sunquake with a second bounce, other sunquakes, and emission associated with the X9.3 flare of 6 September 2017
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Sergei Zharkov, Malcolm Druett, Sarah A. Matthews, Valentina Zharkova, and Satoshi Inoue
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Physics ,Photosphere ,010504 meteorology & atmospheric sciences ,Solar flare ,F300 ,Astrophysics::High Energy Astrophysical Phenomena ,Continuum (design consultancy) ,Astronomy and Astrophysics ,F500 ,Astrophysics ,01 natural sciences ,Seismic wave ,law.invention ,Space and Planetary Science ,law ,Extreme ultraviolet ,0103 physical sciences ,Radiative transfer ,Astrophysics::Solar and Stellar Astrophysics ,010303 astronomy & astrophysics ,0105 earth and related environmental sciences ,Line (formation) ,Flare - Abstract
In this paper we present the interpretation of the observations of the flare from 6 September 2017 reported in Paper I. These include gamma-ray (GR), hard X-ray (HXR), soft X-rays, Lyαline, extreme ultraviolet (EUV), Hα, and white light (WL) emission, which were recorded during the two flaring events 1 (FE1) and 2 (FE2) that occurred at 11:55:37 UT (FE1) and 12:06:40 UT (FE2). Paper I also reported the first detection of the sunquake with first and second bounces of seismic waves combined with four other sunquakes in different locations supported with the observations of HXR, GR, EUV, Hα, and WL emission with strongly varying spatial resolution and temporal coverage. In the current paper, we propose some likely scenarios for heating of flaring atmospheres in the footpoints with sunquakes which were supported with EUV and Hαemission. We used a range of parameters derived from the HXR, EUV, and Hαline observations to generate hydrodynamic models, which can account for the blueshifts derived from the EUV emission and the redshifts observed with the EUV Imaging Spectrometer in the He II line and by the CRisp Imaging Spectro-Polarimeter in the Swedish Solar Telescope in Hαline emission. The parameters of hydrodynamic shocks produced by different beams in flaring atmospheres were used as the initial conditions for another type of hydrodynamic models that were developed for acoustic wave propagation in the solar interior. These models simulate the sets of acoustic waves produced in the interior by the hydrodynamic shocks from atmospheres above deposited in different footpoints of magnetic loops. The Hαline profiles with large redshifts in three kernels (two in FE1 and one in FE2) were interpreted with the full non-local thermodynamic equilibrium radiative simulations in all optically thick transitions (Lyman lines and continuum Hα, Hβ, and Pα) applied for flaring atmospheres with fast downward motions while considering thermal and non-thermal excitation and ionisation of hydrogen atoms by energetic power-law electron beams. The observed Hαline profiles in three kernels were fit with the simulate blue wing emission of the Hαline profiles shifted significantly (by 4–6 Å) towards the line red wings, because of strong downward motions with velocities about 300 km s−1by the shocks generated in flaring atmospheres by powerful beams. The flaring atmosphere associated with the largest sunquake (seismic source 2 in FE1) is found consistent with being induced by a strong hydrodynamic shock produced by a mixed beam deposited at an angle of −30° from the local vertical. We explain the occurrence of a second bounce in the largest sunquake by a stronger momentum delivered by the shock generated in the flaring atmosphere by a mixed beam and deeper depths of the interior where this shock was deposited. Indeed, the shock with mixed beam parameters is found deposited deeply into the interior beneath the flaring atmosphere under the angle to the local vertical that would allow the acoustic waves generated in the direction closer to the surface to conserve enough energy for the second bounces from the interior layers and from the photosphere. The wave characteristics of seismic sources 1 and 3 (in FE1) were consistent with those produced by the shocks generated by similar mixed beams deposited at the angles −(0 − 10)° (seismic source 1) and +30° (seismic source 3) to the local vertical. The differences of seismic signatures produced in the flares of 6 September 2011 and 2017 are also discussed.
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- 2020
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30. On-sky correction of non-common path aberration with the pyramid wavefront sensor
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Glen Herriot, Simone Esposito, Fernando Quiros-Pacheco, Enrico Pinna, Alfio Puglisi, Jean-Pierre Véran, and Guido Agapito
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Physics ,Wavefront ,010308 nuclear & particles physics ,business.industry ,techniques: high angular resolution ,Strehl ratio ,Astronomy and Astrophysics ,First light ,Wavefront sensor ,Astrophysics ,instrumentation: adaptive optics ,01 natural sciences ,Deformable mirror ,law.invention ,Telescope ,Optics ,Space and Planetary Science ,law ,0103 physical sciences ,Pyramid (image processing) ,business ,Adaptive optics ,010303 astronomy & astrophysics - Abstract
The paper deals with with the on-sky performance of the pyramid wavefront sensor-based Adaptive Optics (AO) systems. These wavefront sensors are of great importance, being used in all first light AO systems of the ELTs (E-ELT, GMT, and TMT), currently in design phase. In particular, non-common path aberrations (NCPAs) are a critical issue encountered when using an AO system to produce corrected images in an associated astronomical instrument. The AO wavefront sensor (WFS) and the supported scientific instrument typically use a series of different optical elements, thus experiencing different aberrations. The usual way to correct for such NCPAs is to introduce a static offset in the WFS signals. In this way, when the AO loop is closed the sensor offsets are zeroed and the deformable mirror converges to the shape required to null the NCPA. The method assumes that the WFS operation is linear and completely described by some pre-calibrated interaction matrix. This is not the case for some frequently used wavefront sensors like the Pyramid sensor or a quad-cell Shack-Hartmann sensor. Here we present a method to work in closed-loop with a pyramid wavefront sensor, or more generally a non-linear WFS, introducing a wavefront offset that remains stable when AO correction quality changes due to variations in external conditions like star brightness, seeing, and wind speed. The paper details the methods with analytical and numerical considerations. Then we present results of tests executed at the LBT telescope, in daytime and on sky, using the FLAO system and LUCI2 facility instrument. The on-sky results clearly show the successful operation of the method that completely nulls NCPA, recovering diffraction-limited images with about 70% Strehl ratio in H band in variable seeing conditions. The proposed method is suitable for application to the above-mentioned ELT AO systems.
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- 2020
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31. Central molecular zones in galaxies:12CO-to-13CO ratios, carbon budget, andXfactors
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Frank P. Israel
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Physics ,010308 nuclear & particles physics ,Milky Way ,FOS: Physical sciences ,Conversion factor ,chemistry.chemical_element ,Astronomy and Astrophysics ,Astrophysics ,Astrophysics - Astrophysics of Galaxies ,01 natural sciences ,Galaxy ,Photometry (optics) ,Interstellar medium ,chemistry ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,0103 physical sciences ,Radiative transfer ,Dispersion (chemistry) ,010303 astronomy & astrophysics ,Carbon - Abstract
This paper presents ground-based 12CO and 13CO measurements of 126 nearby galaxy centers in various J transitions. More than 60 galaxies were measured in at least four lines. The average relative intensities of the first four 12CO transitions are 1.00 : 0.92 : 0.70 : 0.57. The average 12CO-to-13CO ratios are 13.0, 11.6, and 12.8 for the first three transitiions. The sizes of central CO concentrations are well defined in maps, but poorly determined by multi-aperture photometry. Using radiative transfer models (RADEX), we derived model gas parameters, where the assumed carbon elemental abundances and carbon gas depletion onto dust are the main causes of uncertainty. The new CO data and published [CI] and [CII] data imply that CO, Co, and C+ each represent about one-third of the gas-phase carbon in the molecular interstellar medium in galaxy centers Their mean beam-averaged central molecular hydrogen column density is N(H2) = (1.5+/-0.2) x 10^(21) cm^(2) and CO-to-H2 conversion factors are typically ten times lower than the `standard' Milky Way disk value, with a mean X(CO) = (1.9+/-0.2) x 10^(19) cm^(2)/K km/s. The corresponding [CI]-to-H2 factor is five times higher than X(CO), with X[CI] = (9+/-2) x 10^(19) cm^(2)/K km/s. No unique conversion factor can be determined for [CII]. The low molecular gas content of galaxy centers relative to their CO intensities is explained in roughly equal parts by higher central gas-phase carbon abundances, elevated gas temperatures, and larger gas velocity dispersions than found in galaxy disks., Comment: Main paper 23 pages including 17 figures, appendices 18 pages
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- 2020
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32. Influences of protoplanet-induced three-dimensional gas flow on pebble accretion
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Hiroyuki Kurokawa and Ayumu Kuwahara
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Physics ,010504 meteorology & atmospheric sciences ,Turbulence ,Astronomy and Astrophysics ,Context (language use) ,Mechanics ,Astrophysics ,Protoplanetary disk ,01 natural sciences ,Accretion (astrophysics) ,Physics::Fluid Dynamics ,Flow (mathematics) ,Space and Planetary Science ,Inviscid flow ,Planet ,0103 physical sciences ,Astrophysics::Earth and Planetary Astrophysics ,Pebble ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics ,0105 earth and related environmental sciences - Abstract
Context. Pebble accretion is among the major theories of planet formation. Aerodynamically small particles, called pebbles, are highly affected by the gas flow. A growing planet embedded in a protoplanetary disk induces three-dimensional (3D) gas flow. In our previous work, Paper I, we focused on the shear regime of pebble accretion and investigated the influence of planet-induced gas flow on pebble accretion. In Paper I, we found that pebble accretion is inefficient in the planet-induced gas flow compared to that of the unperturbed flow, particularly when St ≲ 10−3 , where St is the Stokes number.Aims. Following on the findings of Paper I, we investigate the influence of planet-induced gas flow on pebble accretion. We did not consider the headwind of the gas in Paper I. Here, we extend our study to the headwind regime of pebble accretion.Methods. Assuming a nonisothermal, inviscid sub-Keplerian gas disk, we performed 3D hydrodynamical simulations on the spherical polar grid hosting a planet with the dimensionless mass, m = R Bondi ∕H , located at its center, where R Bondi and H are the Bondi radius and the disk scale height, respectively. We then numerically integrated the equation of motion for pebbles in 3D using hydrodynamical simulation data.Results. We first divided the planet-induced gas flow into two regimes: flow-shear and flow-headwind. In the flow-shear regime, where the planet-induced gas flow has a vertically rotational symmetric structure, we find that the outcome is identical to what we obtained in Paper I. In the flow-headwind regime, the strong headwind of the gas breaks the symmetric structure of the planet-induced gas flow. In the flow-headwind regime, we find that the trajectories of pebbles with St ≲ 10−3 in the planet-induced gas flow differ significantly from those of the unperturbed flow. The recycling flow, where gas from the disk enters the gravitational sphere at low latitudes and exits at high latitudes, gathers pebbles around the planet. We derive the flow transition mass analytically, m t, flow , which discriminates between the flow-headwind and flow-shear regimes. From the relation between m , m t, flow and m t, peb , where m t, peb is the transition mass of the accretion regime of pebbles, we classify the results obtained in both Paper I and this study into four groups. In particular, only when the Stokes gas drag law is adopted and m t, peb , m t, flow ), where the accretion and flow regime are both in the headwind regime, the accretion probability of pebbles with St ≲ 10−3 is enhanced in the planet-induced gas flow compared to that of the unperturbed flow.Conclusions. Combining our results with the spacial variety of turbulence strength and pebble size in a disk, we conclude that the planet-induced gas flow still allows for pebble accretion in the early stage of planet formation. The suppression of pebble accretion due to the planet-induced gas flow occurs only in the late stage of planet formation, more specifically, in the inner region of the disk. This may be helpful for explaining the distribution of exoplanets and the architecture of the Solar System, both of which have small inner and large outer planets.
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- 2020
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33. Catching drifting pebbles
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Beibei Liu, Chris W. Ormel, and Low Energy Astrophysics (API, FNWI)
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010504 meteorology & atmospheric sciences ,FOS: Physical sciences ,Astrophysics ,01 natural sciences ,Physics::Fluid Dynamics ,Settling ,Planet ,0103 physical sciences ,Pebble ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics ,0105 earth and related environmental sciences ,Physics ,Earth and Planetary Astrophysics (astro-ph.EP) ,Turbulent diffusion ,Turbulence ,Computer Science::Information Retrieval ,Equations of motion ,Astronomy and Astrophysics ,Mechanics ,Stars ,13. Climate action ,Space and Planetary Science ,Astrophysics::Earth and Planetary Astrophysics ,Protoplanet ,Astrophysics - Earth and Planetary Astrophysics - Abstract
Turbulence plays a key role in the transport of pebble-sized particles. It also affects the ability of pebbles to be accreted by protoplanets, because it stirs pebbles out of the disk midplane. In addition, turbulence can suppress pebble accretion once the relative velocities become too large for the settling mechanism to be viable. Following Paper I, we aim to quantify these effects by calculating the pebble accretion efficiency $\varepsilon$ using three-body simulations. To model the effect of turbulence on the pebbles, we derive a stochastic equation of motion (SEOM) applicable to stratified disk configurations. In the strong coupling limit (ignoring particle inertia) the limiting form of this equation agrees with previous works. We conduct a parameter study and calculate $\varepsilon$ in 3D, varying pebble and gas (turbulence) properties and accounting for the planet inclination. We find that strong turbulence suppresses pebble accretion through turbulent diffusion, agreeing within factors of order unity with previous works. Another reduction of $\varepsilon$ occurs when the turbulent rms motions are large and the settling mechanism fails. Efficiency-wise, the outer disk regions are more affected by turbulence than the inner regions. At the location of the H$_2$O iceline, planets around low-mass stars achieve much higher efficiencies. Including the results from Paper I, we present a framework to obtain $\varepsilon$ under general circumstances., Comment: accepted version
- Published
- 2018
34. Using the infrared iron lines to probe solar subsurface convection
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Ivan Milic, Andreas Lagg, and H. N. Smitha
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Convection ,Physics ,010308 nuclear & particles physics ,Infrared ,FOS: Physical sciences ,Astronomy and Astrophysics ,Astrophysics ,01 natural sciences ,Computational physics ,Astrophysics - Solar and Stellar Astrophysics ,Space and Planetary Science ,0103 physical sciences ,Astrophysics::Solar and Stellar Astrophysics ,010303 astronomy & astrophysics ,Solar and Stellar Astrophysics (astro-ph.SR) - Abstract
Studying the properties of the solar convection using high-resolution spectropolarimetry began in the early 90's with the focus on observations in the visible wavelength regions. Its extension to the infrared (IR) remains largely unexplored. The IR iron lines around 15600\,$\rm{\AA}$, most commonly known for their high magnetic sensitivity, also have a non-zero response to line-of-sight velocity below $\log (\tau)=0.0$. In this paper we aim to tap this potential to explore the possibility of using them to measure sub-surface convective velocities. By assuming a snapshot of a three-dimensional magnetohydrodynamic simulation to represent the quiet Sun, we investigate how well the iron IR lines can reproduce the LOS velocity in the cube and up to what depth. We use the recently developed spectropolarimetric inversion code SNAPI and discuss the optimal node placements for the retrieval of reliable results from these spectral lines. We find that the IR iron lines can measure the convective velocities down to $\log (\tau)=0.5$, below the photosphere, not only at original resolution of the cube but also when degraded with a reasonable spectral and spatial PSF and stray light. Meanwhile, the commonly used Fe~{\sc i} 6300\,\AA{} line pair performs significantly worse. Our investigation reveals that the IR iron lines can probe the subsurface convection in the solar photosphere. This paper is a first step towards exploiting this diagnostic potential., Comment: 11 pages, Accepted for publication in Astronomy and Astrophysics
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- 2019
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35. Nuclear angular momentum of early-type galaxies hosting nuclear star clusters
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Mariya Lyubenova and Athanassia Tsatsi
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Physics ,Stellar kinematics ,Angular momentum ,010308 nuclear & particles physics ,Milky Way ,FOS: Physical sciences ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Astrophysics - Astrophysics of Galaxies ,01 natural sciences ,Galaxy ,Star cluster ,Space and Planetary Science ,Bulge ,Astrophysics of Galaxies (astro-ph.GA) ,Globular cluster ,0103 physical sciences ,Fornax Cluster ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics - Abstract
Nucleation is a common phenomenon in all types of galaxies and at least 70% of them host nuclear star clusters (NSCs) in their centres. Many of the NSCs co-habit with super-massive black holes and follow similar scaling relations with host galaxy properties. NSCs, unlike black holes, preserve the signature of their evolutionary path imprinted onto their kinematics and stellar populations. Thus their study provides us with important information about the formation of galactic nuclei. In this paper we explored the angular momentum of the nuclei of six intermediate mass (9.7 > log(Mdyn/M_sun) > 10.6) early-type galaxies in the Fornax cluster that host NSCs. Our goal was to derive a link between the nuclear angular momentum and the proposed formation scenarios of NSCs. We used Adaptive Optics assisted IFU observations with VLT/SINFONI to derive the spatially resolved stellar kinematics of the galaxy nuclei. We measured their specific stellar angular momenta ($\lambda_\mathrm{Re}$), and compared these with Milky Way globular clusters and N-body simulations of NSC formation. We found that all studied nuclei exhibit varied stellar kinematics. Their specific stellar angular momenta and ellipticities are similar to Milky Way globular clusters (GCs). Five out of six galaxy nuclei are consistent with the $\lambda_\mathrm{Re} - \epsilon_\mathrm{e}$ of simulated NSCs embedded in a contaminating nuclear bulge that have formed via the in-spiralling and merging of GCs. It has previously been suggested that the NSCs in higher mass galaxies, like the ones studied in this paper, form via dissipational sinking of gas onto the galactic nuclei with hints that some might also involve the merger of GCs. Here we showed that we cannot exclude the pure GC merging scenario as a viable path for the formation of NSCs., Comment: 8 pages, 3 figures, accepted for publication in A&A
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- 2019
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36. Magnetic field vector ambiguity resolution in a quiescent prominence observed on two consecutive days
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V. Bommier, T. Kalewicz, 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), and PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
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Hanle effect ,010504 meteorology & atmospheric sciences ,FOS: Physical sciences ,Astrophysics ,magnetic fields ,01 natural sciences ,Solar prominence ,prominences ,symbols.namesake ,0103 physical sciences ,Stokes parameters ,Sun: magnetic fields ,010303 astronomy & astrophysics ,Solar and Stellar Astrophysics (astro-ph.SR) ,0105 earth and related environmental sciences ,Physics ,polarization ,Ambiguity resolution ,[SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR] ,Scattering ,Astronomy and Astrophysics ,Polarization (waves) ,Computational physics ,Magnetic field ,Sun: filaments ,Astrophysics - Solar and Stellar Astrophysics ,Space and Planetary Science ,symbols ,Solar rotation ,[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph] - Abstract
Magnetic field vector measurements are always ambiguous, that is, two or more field vectors are solutions of the observed polarisation. The aim of the present paper is to solve the ambiguity by comparing the ambiguous field vectors obtained in the same prominence observed on two consecutive days. The effect of the solar rotation is to modify the scattering angle of the prominence radiation, which modifies the symmetry of the ambiguous solutions. This method, which is a kind of tomography, was successfully applied in the past to the average magnetic field vector of 20 prominences observed at the Pic du Midi. The aim of the present paper is to apply this method to a prominence observed with spatial resolution at the THEMIS telescope (European site at Izana, Tenerife Island). The magnetic field vector is measured by interpretation of the Hanle effect observed in the He I D3 5875.6 A line, within the horizontal field vector hypothesis for simplicity. The ambiguity is first solved by comparing the two pairs of solutions obtained for a "big pixel" determined by averaging the observed Stokes parameters in a large region at the prominence centre. Each pixel is then disambiguated by selecting the closest solution in a propagation from the prominence centre to the prominence boundary. The results previously obtained on averaged prominences are all recovered. The polarity is found to be inverse with a small angle of about -21{\deg} between the magnetic field vector and the long axis of the filament. The magnetic field strength of about 6 G is found to slightly increase with height, as previously observed. The new result is the observed decrease with height, of the absolute value of the angle between the magnetic field vector and the long axis of the filament. This result is in excellent agreement with prominence magnetohydrodynamical models., Comment: 8 pages, 8 figures, version v5, accepted in Astronomy & Astrophysics, Section "The Sun"
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- 2019
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37. Barium and related stars, and their white-dwarf companions
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D. Karinkuzhi, Alain Jorissen, S. Shetye, Henri M. J. Boffin, S. Van Eck, H. Van Winckel, and Ana Escorza
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010504 meteorology & atmospheric sciences ,Metallicity ,FOS: Physical sciences ,chemistry.chemical_element ,Abundances [Stars] ,Astrophysics ,Computer Science::Digital Libraries ,01 natural sciences ,peculiar [Stars] ,spectroscopic [Binaries] ,0103 physical sciences ,Asymptotic giant branch ,010303 astronomy & astrophysics ,Astrophysique ,Solar and Stellar Astrophysics (astro-ph.SR) ,0105 earth and related environmental sciences ,Physics ,Barium star ,Mass distribution ,Astrophysics::Instrumentation and Methods for Astrophysics ,White dwarfs ,White dwarf ,Astronomy and Astrophysics ,Barium ,AGB and post-AGB [Stars] ,Astronomie ,Giant star ,Physics::History of Physics ,Sciences de l'espace ,Stars ,Astrophysics - Solar and Stellar Astrophysics ,chemistry ,Space and Planetary Science - Abstract
Context. Barium and S stars without technetium are red giants and are suspected of being members of binary systems due to their overabundances in heavy elements. These elements are produced by the s-process of nucleosynthesis, despite the stars not being evolved enough to be able to activate the s-process in their interiors. A companion formerly on the asymptotic giant branch (now a white dwarf) is supposed to be responsible for the barium-And S-star enrichment in s-process elements through mass transfer. Aims. This paper provides both long-period and revised orbits for barium and S stars, adding to previously published orbits. The sample of barium stars with strong anomalies (i.e. those classified as Ba3, Ba4, or Ba5 in the Warner scale) comprises all known stars of that kind, and in that sense forms a complete sample that allows us to investigate several orbital properties of these post-mass-Transfer binaries in an unbiased way. Methods. Orbital elements are derived from radial velocities collected from a long-Term radial-velocity monitoring campaign performed with the HERMES spectrograph mounted on the Mercator 1.2m telescope. These new measurements were combined with older, CORAVEL measurements. With the aim of investigating possible correlations between orbital properties and abundances, we also collected a set of abundances for barium stars with orbital elements that is as homogeneous as possible. When unavailable in the literature, abundances were derived from high-resolution HERMES spectra. Results. We find orbital motion for all barium and extrinsic S stars monitored (except for the mild barium star HD95345). We obtain the longest period known so far for a spectroscopic binary involving an S star, namely 57 Peg with a period of the order of 100-500 yr. We present the mass distribution for the barium stars, which ranges from 1 to 3 Ṁ, with a tail extending up to 5 M ·in the case of mild barium stars. This high-mass tail is mostly comprised of high-metallicity objects ([Fe/H] ≥-0:1). The distribution of the companion masses was extracted from the barium-star mass distribution combined with the finding that Q = f (MBa; MWD)= sin3 i = M3 WD=(MBa + MWD)2 is peaked at 0:057 ± 0:009 and 0:036 ± 0:027 M ·for strong and mild barium stars, respectively ( f (MBa; MWD) is the mass function obtained from the orbital elements of spectroscopic binaries with one observable spectrum). Mass functions are compatible with WD companions whose masses range from 0.5 to 1 M·. Strong barium stars have a tendency to be found in systems with shorter periods than mild barium stars, although this correlation is rather lose, with metallicity and WD mass also playing a role. Using the initialfinal mass relationship established for field WDs, we derived the distribution of the mass ratio q0 = MAGB;ini=MBa (where MAGB;ini is the WD progenitor initial mass, i.e. the mass of the former primary component of the system) which is a proxy for the initial mass ratio (the less mass the barium star has accreted, the better the proxy). It appears that the distribution of q0 is highly nonuniform, and significantly different for mild and strong barium stars, the latter being characterized by values mostly in excess of 1.4, whereas mild barium stars occupy the range 1-1.4. Conclusions. The orbital properties presented in this paper pave the way for a comparison with binary-evolution and nucleosynthesis models, which should account for the various significant correlations found between abundances and dynamical parameters (e.g. between MBa on one hand and MWD, [Fe/H], and [s/Fe] on the other hand, between q0 and [s/Fe], between P and e, and between P and [s/Fe] altogether)., SCOPUS: ar.j, info:eu-repo/semantics/published
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- 2019
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38. Influence of surface roughness on diffraction in the externally occulted Lyot solar coronagraph
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David Mary, Raphaël Rougeot, Claude Aime, and Rémi Flamary
- Subjects
Diffraction ,Wavefront ,Physics ,Lyot stop ,business.industry ,Astronomy and Astrophysics ,Solar radius ,Context (language use) ,Astrophysics ,01 natural sciences ,law.invention ,010309 optics ,Telescope ,Optics ,Space and Planetary Science ,law ,0103 physical sciences ,Surface roughness ,business ,010303 astronomy & astrophysics ,Coronagraph - Abstract
Context. The solar coronagraph ASPIICS will fly on the future ESA formation flying mission Proba-3. The instrument combines an external occulter of diameter 1.42 m and a Lyot solar coronagraph of 5 cm diameter, located downstream at a distance of 144 m. Aims. The theoretical performance of the externally occulted Lyot coronagraph has been computed by assuming perfect optics. In this paper, we improve related modelling by introducing roughness scattering effects from the telescope. We have computed the diffraction at the detector, that we compare to the ideal case without perturbation to estimate the performance degradation. We have also investigated the influence of sizing the internal occulter and the Lyot stop, and we performed a sensitivity analysis on the roughness. Methods. We have built on a recently published numerical model of diffraction propagation. The micro-structures of the telescope are built by filtering a white noise with a power spectral density following an isotropic ABC function, suggested by Harvey scatter theory. The parameters were tuned to fit experimental data measured on ASPIICS lenses. The computed wave front error was included in the Fresnel wave propagation of the coronagraph. A circular integration over the solar disk was performed to reconstruct the complete diffraction intensity. Results. The level of micro-roughness is 1.92 nm root-mean-square. Compared to the ideal case, in the plane of the internal occulter, the diffraction peak intensity is reduced by ≃0.001%. However, the intensity outside the peak increases by 12% on average, up to 20% at 3 R⊙, where the mask does not filter out the diffraction. At detector level, the diffraction peak remains ≃10−6 at 1.1 R⊙, similar to the ideal case, but the diffraction tail at large solar radius is much higher, up to one order of magnitude. Sizing the internal occulter and the Lyot stop does not improve the rejection, as opposed to the ideal case. Conclusions. Besides these results, this paper provides a methodology to implement roughness scattering in the wave propagation model for the solar coronagraph.
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- 2019
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39. A unified accretion-ejection paradigm for black hole X-ray binaries
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F. Cangemi, Mickael Coriat, R. Belmont, Stephane Corbel, Jonathan Ferreira, Jerome Rodriguez, Maïca Clavel, G. Marcel, Julien Malzac, G. Henri, P.-O. Petrucci, 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]), Villanova University, Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Département d'Astrophysique (ex SAP) (DAP), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Unité Scientifique de la Station de Nançay (USN), Centre National de la Recherche Scientifique (CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers en région Centre (OSUC), 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 d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO), Centre National d’Etudes Spatiales (CNES)Programme National des Hautes Energies (PNHE), ANR-12-BS05-0009,CHAOS,Caractérisation des processus d'accretion-ejection dans les systèmes binaires compacts(2012), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Université d'Orléans (UO)-Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-Centre National de la Recherche Scientifique (CNRS), Villanova University [USA], Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Observatoire des Sciences de l'Univers en région Centre (OSUC), Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), and PSL Research University (PSL)-PSL Research University (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris
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Angular momentum ,Spectral shape analysis ,Astrophysics::High Energy Astrophysical Phenomena ,black hole physics ,FOS: Physical sciences ,Astrophysics ,magnetohydrodynamics (MHD) ,01 natural sciences ,Spectral line ,X-rays: binaries ,accretion ,Accretion disc ,0103 physical sciences ,010306 general physics ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics ,High Energy Astrophysical Phenomena (astro-ph.HE) ,[PHYS]Physics [physics] ,Physics ,accretion disks ,X-ray ,Astronomy and Astrophysics ,Plasma ,Accretion (astrophysics) ,ISM: jets and outflows ,Space and Planetary Science ,Activity cycle ,Astrophysics::Earth and Planetary Astrophysics ,[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph] ,Astrophysics - High Energy Astrophysical Phenomena - Abstract
Transients XrB exhibit different spectral shapes during their evolution. In luminosity-color diagrams, their X-ray behavior forms unexplained q-shaped cycles. We proposed a framework where the innermost regions of the accretion disk evolve as a response to variations imposed in the outer regions. These variations lead not only to modifications of the inner disk accretion rate $\dot m_{in}$ but also to the evolution of the transition radius $r_J$ between two regions. The outermost region is a standard accretion disk (SAD), whereas the innermost region is a jet-emitting disk (JED) where all the disk angular momentum is carried away vertically by two self-confined jets. In the previous papers of this series, it has been shown that such a configuration reproduces the typical spectral properties of the five canonical XrB states. The aim of this paper is now to replicate all X-ray spectra and radio emission observed during GX 339-4 2010-2011 outburst. We use the 2T plasma code presented in papers II and III, and design an automatic fitting procedure that gives the parameters $(\dot m_{in},r_J)$ that best fit each X-ray spectrum. We use RXTE/PCA X-ray data spread over 438 days, together with radio observations at 9 GHz (ATCA). We obtain the time distributions of $\dot m_{in}$ and $r_J$ that uniquely reproduce the X-ray luminosity and the spectral shape of the whole cycle. Using the classical self-absorbed jet synchrotron emission model, the JED-SAD configuration reproduces also very satisfactorily the radio properties, in particular the switch-off and -on events and the radio-X-ray correlation. Within the JED-SAD framework, radio emission can be used to constrain the underlying disk configuration. If this result is confirmed using other outbursts from GX 339-4 or other X-ray binaries, then radio could be indeed used as another means to indirectly probe disk physics., Accepted for publication in A&A, 11 pages, 7 figures
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- 2019
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40. The CORALIE survey for southern extrasolar planets
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J. Rey, Francesco Pepe, Maxime Marmier, Nuno C. Santos, C. Lovis, H. Giles, Arthur Choplin, Damien Ségransan, Hugh P. Osborn, Fatemeh Motalebi, Vivien Bonvin, Oliver Turner, Louise D. Nielsen, J.-B. Delisle, P. Bratschi, F. Cersullo, T. Roger, Aurélien Wyttenbach, P. Figueira, M. Girard, A. Deline, U. Conod, E. L. Rickman, David V. Martin, L. Weber, G. Ottoni, D. Queloz, M. Stalport, Stéphane Udry, François Bouchy, Baptiste Lavie, M. Mayor, A. Suárez Mascareño, L. A. dos Santos, M. Raimbault, Amaury H. M. J. Triaud, Bruno Chazelas, Romain Allart, Julia V. Seidel, Queloz, Didier [0000-0002-3012-0316], Apollo - University of Cambridge Repository, Laboratoire d'Astrophysique de Marseille (LAM), 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)
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planets and satellites: detection ,Brown dwarf ,Context (language use) ,Astrophysics ,01 natural sciences ,Planet ,techniques: radial velocities ,0103 physical sciences ,Astrophysics::Solar and Stellar Astrophysics ,planetary systems ,010303 astronomy & astrophysics ,Orbital elements ,Physics ,[SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph] ,010308 nuclear & particles physics ,Astronomy and Astrophysics ,Planetary system ,binaries: visual ,Exoplanet ,[SDU]Sciences of the Universe [physics] ,13. Climate action ,Space and Planetary Science ,Astrophysics::Earth and Planetary Astrophysics ,Low Mass ,Main sequence ,Astrophysics - Earth and Planetary Astrophysics - Abstract
International audience; Context. Since 1998, a planet-search around main sequence stars within 50 pc in the southern hemisphere has been underway with the CORALIE spectrograph at La Silla Observatory. Aims: With an observing time span of more than 20 yr, the CORALIE survey is able to detect long-term trends in data with masses and separations large enough to select ideal targets for direct imaging. Detecting these giant companion candidates will allow us to start bridging the gap between radial-velocity-detected exoplanets and directly imaged planets and brown dwarfs. Methods: Long-term precise Doppler measurements with the CORALIE spectrograph reveal radial-velocity signatures of massive planetary companions and brown dwarfs on long-period orbits. Results: In this paper, we report the discovery of new companions orbiting HD 181234, HD 13724, HD 25015, HD 92987 and HD 50499. We also report updated orbital parameters for HD 50499b, HD 92788b and HD 98649b. In addition, we confirm the recent detection of HD 92788c. The newly reported companions span a period range of 15.6-40.4 yr and a mass domain of 2.93-26.77 MJup, the latter of which straddles the nominal boundary between planets and brown dwarfs. Conclusions: We report the detection of five new companions and updated parameters of four known extrasolar planets. We identify at least some of these companions to be promising candidates for imaging and further characterisation. The radial velocity measurements and additional data products discussed in this paper are available on the DACE web platform at https://dace.unige.ch/radialVelocities. See the appendix for a direct link to the individual target data products. A copy of the data is also available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/625/A71Based on observations collected with the CORALIE spectrograph mounted on the 1.2 m Swiss telescope at La Silla Observatory and with the HARPS spectrograph on the ESO 3.6 m telescope at La Silla (ESO, Chile).
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- 2019
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41. Searching for g modes
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T. Corbard, T. Appourchaux, Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, and COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
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Physics ,010504 meteorology & atmospheric sciences ,Series (mathematics) ,Mode (statistics) ,FOS: Physical sciences ,Spectral density ,Astronomy and Astrophysics ,Astrophysics ,01 natural sciences ,Computational physics ,Travel time ,Astrophysics - Solar and Stellar Astrophysics ,Space and Planetary Science ,0103 physical sciences ,book.illustrator ,[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph] ,Unconfirmed ,010303 astronomy & astrophysics ,book ,Solar and Stellar Astrophysics (astro-ph.SR) ,0105 earth and related environmental sciences - Abstract
The recent claimed detection of g modes was obtained from the analysis of the power spectrum of the time series of round-trip travel time of p modes. The goal of this paper is to reproduce these results on which the claims are based for confirming or invalidating the detection of g modes with the method used to make the claims. We computed the time series of round-trip travel time using the procedure given in Fossat et al. (2017), and used different variations of the times series for comparison. We used the recently calibrated GOLF data (published in Paper I) with different sampling, different photomultipliers, different length of data for reproducing the analysis. We also correlated the power spectrum with an asymptotic model of g-mode frequencies in a similar manner to Fossat and Schmider (2018). We devised a scheme for optimising the correlation both for pure noise and for the GOLF data. We confirm the analysis performed in Fossat et al. (2017) but draw different conclusions. Their claims of detection of g modes cannot be confirmed when changing parameters such as sampling interval, length of time series, or photomultipliers. Other instrument such as GONG and BiSON do not confirm their detection. We also confirm the analysis performed in Fossat and Schmider (2018), but again draw different conclusions. For GOLF, the correlation of the power spectrum with the asymptotic model of g-mode frequencies for $l=1$ and $l=2$ show a high correlation at lag=0 and at lag corresponding to the rotational splitting $\nu_l$, but the same occurs for pure noise due to the large number of peaks present in the model. In addition, other very different parameters defining the asymptotic model also provide a high correlation at these lags. We conclude that the detection performed in Fossat and Schmider (2018) is an artefact of the methodology., Comment: 11 pages, 10 figures, Accepted March 4, 2019
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- 2019
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42. PÉGASE.3: A code for modeling the UV-to-IR/submm spectral and chemical evolution of galaxies with dust
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B. Rocca-Volmerange and Michel Fioc
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Luminous infrared galaxy ,Physics ,010308 nuclear & particles physics ,Star formation ,Extinction (astronomy) ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Astrophysics - Astrophysics of Galaxies ,01 natural sciences ,Galaxy ,Interstellar medium ,Supernova ,Astrophysics - Solar and Stellar Astrophysics ,Space and Planetary Science ,0103 physical sciences ,Radiative transfer ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,Astrophysics - Instrumentation and Methods for Astrophysics ,010303 astronomy & astrophysics ,Stellar evolution ,Astrophysics::Galaxy Astrophysics - Abstract
A code computing consistently the evolution of stars, gas and dust, as well as the energy they radiate, is required to derive reliably the history of galaxies by fitting synthetic SEDs to multiwavelength observations. The new code P\'egase.3 described in this paper extends to the far-IR/submm the UV-to-near-IR modeling provided by previous versions of P\'egase. It first computes the properties of single stellar populations at various metallicities. It then follows the evolution of the stellar light of a galaxy and the abundances of the main metals in the ISM, assuming some scenario of mass assembly and star formation. It simultaneously calculates the masses of the various grain families, the optical depth of the galaxy and the attenuation of the SED through the diffuse ISM in spiral and spheroidal galaxies, using grids of radiative transfer precomputed with Monte Carlo simulations taking scattering into account. The code determines the mean radiation field and the temperature probability distribution of stochastically heated individual grains. It then sums up their spectra to yield the overall emission by dust in the diffuse ISM. The nebular emission of the galaxy is also computed, and a simple modeling of the effects of dust on the SED of star-forming regions is implemented. The main outputs are UV-to-submm SEDs of galaxies from their birth up to 20 Gyr, colors, masses of galactic components, ISM abundances of metallic elements and dust species, supernova rates. The temperatures and spectra of individual grains are also available. The paper discusses several of these outputs for a scenario representative of Milky Way-like spirals. P\'egase.3 is fully documented and its Fortran 95 source files are public. The code should be especially useful for cosmological simulations and to interpret future mid- and far-IR data, whether obtained by JWST, LSST, Euclid or e-ELT., Comment: 15 pages. In press in A&A. Source files of the code available at http://www.iap.fr/users/fioc/Pegase/Pegase.3/ (and http://www.iap.fr/pegase/); documentation at arXiv:1902.02198
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43. Measuring precise radial velocities on individual spectral lines
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Xavier Dumusque
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Earth and Planetary Astrophysics (astro-ph.EP) ,Physics ,010308 nuclear & particles physics ,FOS: Physical sciences ,Astronomy and Astrophysics ,Context (language use) ,Function (mathematics) ,Astrophysics ,01 natural sciences ,Spectral line ,Standard deviation ,Stars ,Astrophysics - Solar and Stellar Astrophysics ,Space and Planetary Science ,Colors of noise ,0103 physical sciences ,Line (geometry) ,Astrophysics - Instrumentation and Methods for Astrophysics ,Instrumentation and Methods for Astrophysics (astro-ph.IM) ,010303 astronomy & astrophysics ,Solar and Stellar Astrophysics (astro-ph.SR) ,Astrophysics - Earth and Planetary Astrophysics ,Data reduction - Abstract
Stellar activity is the main limitation to the detection of Earth-twins using the RV technique. Despite many efforts in trying to mitigate the effect of stellar activity using empirical and statistical techniques, it seems that we are facing an obstacle that will be extremely difficult to overcome using current techniques. In this paper, we investigate a novel approach to derive precise RVs considering the wealth of information present in high-resolution spectra. This new method consists in building a master spectrum from all observations and measure the RVs of each spectral line in a spectrum relative to it. When analysing several spectra, the final product is the RVs of each line as a function of time. We demonstrate on three stars intensively observed with HARPS that our new method gives RVs that are extremely similar to the ones derived from the HARPS data reduction software. Our new approach to derive RVs demonstrates that the non-stability of daily HARPS wavelength solution induces night-to-night RV offsets with an standard deviation of 0.4 m/s, and we propose a solution to correct for this systematic. Finally, and this is probably the most astrophysically relevant result of this paper, we demonstrate that some spectral lines are strongly affected by stellar activity while others are not. By measuring the RVs on two carefully selected subsample of spectral lines, we demonstrate that we can boost by a factor of 2 or mitigate by a factor of 1.6 the red noise induced by stellar activity in the 2010 RVs of Alpha Cen B. By measuring the RVs of each spectral line, we are able to reach the same RV precision as other approved techniques. In addition, this new approach allows to demonstrate that each line is differently affected by stellar activity. Preliminary results show that studying in details the behaviour of each spectral line is probably the key to overcome stellar activity., 14 pages (plus 8 pages of Appendix), 17 figures, 1 table, Accepted for publication in A&A. Version 2: typo corrected in Equation 1
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- 2018
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44. An efficient code to solve the Kepler equation
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Virginia Raposo-Pulido and Jesús Peláez
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Physics ,Code (set theory) ,Astronomy and Astrophysics ,Astrophysics ,Kepler's equation ,01 natural sciences ,Celestial mechanics ,symbols.namesake ,Theoretical physics ,Space and Planetary Science ,0103 physical sciences ,symbols ,010306 general physics ,010303 astronomy & astrophysics - Abstract
Context. This paper introduces a new approach for solving the Kepler equation for hyperbolic orbits. We provide here the Hyperbolic Kepler Equation–Space Dynamics Group (HKE–SDG), a code to solve the equation. Methods. Instead of looking for new algorithms, in this paper we have tried to substantially improve well-known classic schemes based on the excellent properties of the Newton–Raphson iterative methods. The key point is the seed from which the iteration of the Newton–Raphson methods begin. If this initial seed is close to the solution sought, the Newton–Raphson methods exhibit an excellent behavior. For each one of the resulting intervals of the discretized domain of the hyperbolic anomaly a fifth degree interpolating polynomial is introduced, with the exception of the last one where an asymptotic expansion is defined. This way the accuracy of initial seed is optimized. The polynomials have six coefficients which are obtained by imposing six conditions at both ends of the corresponding interval: the polynomial and the real function to be approximated have equal values at each of the two ends of the interval and identical relations are imposed for the two first derivatives. A different approach is used in the singular corner of the Kepler equation – |M| < 0.15 and 1 < e < 1.25 – where an asymptotic expansion is developed. Results. In all simulations carried out to check the algorithm, the seed generated leads to reach machine error accuracy with a maximum of three iterations (∼99.8% of cases with one or two iterations) when using different Newton–Raphson methods in double and quadruple precision. The final algorithm is very reliable and slightly faster in double precision (∼0.3 s). The numerical results confirm the use of only one asymptotic expansion in the whole domain of the singular corner as well as the reliability and stability of the HKE–SDG. In double and quadruple precision it provides the most precise solution compared with other methods.
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- 2018
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45. Single site observations of TESS single transit detections
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Don Pollacco, Peter J. Wheatley, Benjamin F. Cooke, Richard G. West, and James McCormac
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Physics ,010504 meteorology & atmospheric sciences ,Astronomy and Astrophysics ,Context (language use) ,Astrophysics ,Planetary system ,01 natural sciences ,Upper and lower bounds ,Exoplanet ,Stars ,Space and Planetary Science ,Planet ,0103 physical sciences ,Satellite ,Transit (astronomy) ,010303 astronomy & astrophysics ,0105 earth and related environmental sciences - Abstract
Context. The Transiting Exoplanet Survey Satellite (TESS) has been successfully launched and has begin data acquisition. To expedite the science that may be performed with the resulting data it is necessary to gain a good understanding of planetary yields. Given the observing strategy employed by TESS the probability of detecting single transits in long period systems is increased. These systems require careful consideration. Aims. We aim to simulate the number of TESS transit detections during its two-year mission with a particular emphasis on single transits. We also aim to determine the feasibility of ground-based follow-up observations from a single site. Methods. A distribution of planets was simulated around the approximately four million stars in the TESS candidate target list. These planets were tested for detectable transits and characterised. Based on simulated parameters the single transit detections were further analysed to determine which are amenable to ground-based follow-up. Results. TESS will discover an approximate lower bound of 4700 planets with around 460 being single transits. A large fraction of these will be observable from a single ground-based site. This paper finds that, in a single year, approximately 1000 transit events of around 320 unique TESS single transit detections are theoretically observable. Conclusions. As we consider longer period exoplanets, the need for exploring single transit detections increases. For periods ≳45 days the number of single transit detections outnumber multitransits by a factor of three (82 ± 18 and 25 ± 7, respectively) a factor which only grows as longer period detections are considered. Therefore, based on this paper, it is worth expending the extra effort required to follow-up these more challenging, but potentially very rewarding, discoveries. Additionally, we conclude that a large fraction of these targets can be theoretically observed from a single ground-based site. However, further work is required to determine whether these follow-up efforts are feasible when accounting for target specific criteria.
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- 2018
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46. Tracing the evolution of radiation-MHD simulations of solar and stellar atmospheres in the Lagrangian frame
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Jorrit Leenaarts
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Physics ,010504 meteorology & atmospheric sciences ,Computer Science::Information Retrieval ,Frame (networking) ,Stellar atmosphere ,FOS: Physical sciences ,Astronomy ,Astronomy and Astrophysics ,Context (language use) ,Astrophysics ,Tracing ,Radiation ,01 natural sciences ,symbols.namesake ,Astrophysics - Solar and Stellar Astrophysics ,Space and Planetary Science ,0103 physical sciences ,symbols ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,Magnetohydrodynamics ,010303 astronomy & astrophysics ,Solar and Stellar Astrophysics (astro-ph.SR) ,Lagrangian ,0105 earth and related environmental sciences - Abstract
Context: Radiation-MHD simulations have become a standard tool to investigate the physics of solar and stellar atmospheres. Aims: The aim of this paper to present a method that allows efficient and accurate analysis of flows in such simulations in the Lagrangian frame. Methods: This paper presents a method that allows the construction of pathlines given a seed point that can be chosen freely at any location and at any time during the simulation where the simulation state is stored. The method is based on passive tracer particles. Through injection of particles in expanding regions the occurrence of particle-free volumes is avoided, even in the case of strongly compressive flows. Results:The method was implemented in the solar and stellar atmosphere simulation code Bifrost. It is efficient and accurate. As examples I present an analysis of a gas parcel in the convection zone and a particle in the solar transition region.}, Comment: Accepted for publication in A&A
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- 2018
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47. The host of the Type I SLSN 2017egm
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R. P. Hedrosa, Rubén García-Benito, David Alexander Kann, M. Della Valle, A. de Ugarte Postigo, Christina C. Thöne, D. Galadí-Enríquez, Luca Izzo, Zach Cano, K. Bensch, ITA, USA, ESP, Ministerio de Economía y Competitividad (España), and European Commission
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Galaxies: general ,Stellar population ,Metallicity ,Population ,FOS: Physical sciences ,Astrophysics ,01 natural sciences ,0103 physical sciences ,individual: 2017egm [Supernovae] ,education ,010303 astronomy & astrophysics ,High Energy Astrophysical Phenomena (astro-ph.HE) ,Physics ,education.field_of_study ,Spiral galaxy ,010308 nuclear & particles physics ,Star formation ,general [Galaxies] ,Astronomy and Astrophysics ,Astrophysics - Astrophysics of Galaxies ,Galaxy ,Supernova ,Stars ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,Astrophysics - High Energy Astrophysical Phenomena ,Supernovae: individual: 2017egm - Abstract
Context. Type I superluminous supernova (SLSN) host galaxies are predominantly low-metallicity, highly star-forming (SF) dwarfs. One of the current key questions is whether Type I SLSNe can only occur in such environments and hosts. Aims. Here we present an integral-field study of the massive, high-metallicity spiral NGC 3191, the host of SN 2017egm, the closest Type I SLSN known to date. We use data from PMAS/CAHA and the public MaNGA survey to shed light on the properties of the SLSN site and the origin of star formation in this non-starburst spiral galaxy. Methods. We map the physical properties of different H ii regions throughout the galaxy and characterise their stellar populations using the STARLIGHT fitting code. Kinematical information allows us to study a possible interaction with its neighbouring galaxy as the origin of recent star formation activity which could have caused the SLSN. Results. NGC 3191 shows intense star formation in the western part with three large SF regions of low metallicity. Taking only the properties of emitting gas, the central regions of the host have a higher metallicity, a lower specific star formation rate, and lower ionisation. Modelling the stellar populations gives a different picture: the SLSN region has two dominant stellar populations with different ages, the younger one with an age of 2-10 Myr and lower metallicity, likely the population from which the SN progenitor originated. Emission line kinematics of NGC 3191 show indications of interaction with its neighbour MCG+08-19-017 at ∼45 kpc, which might be responsible for the recent starburst. In fact, this galaxy pair has hosted a total of four SNe, 1988B (Type Ia), SN 2003ds (Type Ic in MCG+08-19-017), PTF10bgl (Type II), and 2017egm, underlying the enhanced SF in both galaxies due to interaction. Conclusions. Our study shows that care should be taken when interpreting global host and even gas properties without looking at the stellar population history of the region. The SLSNe seem to be consistent with massive stars (>20 M) requiring low metallicity (, We thank the referee for the constructive comments that have improved the paper. We also thank Steve Schulze and Yan Lin for their important comments to the paper. L.I., C.T., Z.C., A.d.U.P., and D.A.K. acknowledge support from the Spanish research project AYA2014-58381-P. C.T. and A.d.U.P. also acknowledge support from Ramon y Cajal fellowships RyC-2012-09984 and RyC-2012-09975. D.A.K. and Z.C. acknowledge support from Juan de la Cierva Incorporacion fellowships IJCI-2015-26153 and IJCI-2014-21669. R.G.B. acknowledges support from the Spanish Ministerio de Economia y Competitividad, through projects AYA2016-77846-P and AYA2014-57490-P. L.I. wishes to thank Anna Serena Esposito for her kind availability and support in organising the figures presented in this paper.
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48. The Carnegie Supernova Project I
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Wenxiong Li, Mario Hamuy, Gastón Folatelli, S. Holmbo, Mark M. Phillips, C. Corco, B. F. Madore, L. Busta, J. Serón, Miguel Roth, Eric Hsiao, Alexei V. Filippenko, Christopher R. Burns, C. Gonzalez, S. E. Persson, Abdo Campillay, Francisco Salgado, Francesco Taddia, Nidia Morrell, E. Heinrich-Josties, Joseph P. Anderson, J. Anais, S. Castellon, Kevin Krisciunas, Nicholas B. Suntzeff, Wojtek Krzeminski, Carlos Contreras, Maximilian Stritzinger, Luis Boldt, Wendy L. Freedman, and S. Torres-Robledo
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Brightness ,astro-ph.SR ,010504 meteorology & atmospheric sciences ,FOS: Physical sciences ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,01 natural sciences ,Photometry (optics) ,Observatory ,0103 physical sciences ,Astrophysics::Solar and Stellar Astrophysics ,14. Life underwater ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics ,Solar and Stellar Astrophysics (astro-ph.SR) ,0105 earth and related environmental sciences ,astro-ph.HE ,High Energy Astrophysical Phenomena (astro-ph.HE) ,Physics ,Astronomy and Astrophysics ,Redshift ,Supernova ,Astrophysics - Solar and Stellar Astrophysics ,Space and Planetary Science ,Astrophysics::Earth and Planetary Astrophysics ,Astrophysics - High Energy Astrophysical Phenomena ,Data release - Abstract
The first phase of the Carnegie Supernova Project (CSP-I) was a dedicated supernova follow-up program based at the Las Campanas Observatory that collected science data of young, low-redshift supernovae between 2004 and 2009. Presented in this paper is the CSP-I photometric data release of low-redshift stripped-envelope core-collapse supernovae. The data consist of optical (uBgVri) photometry of 34 objects, with a subset of 26 having near-infrared (YJH) photometry. Twenty objects have optical pre-maximum coverage with a subset of 12 beginning at least five days prior to the epoch of B-band maximum brightness. In the near-infrared, 17 objects have pre-maximum observations with a subset of 14 beginning at least five days prior to the epoch of J-band maximum brightness. Analysis of this photometric data release is presented in companion papers focusing on techniques to estimate host-galaxy extinction (Stritzinger et al., submitted) and the light-curve and progenitor star properties of the sample (Taddia et al., submitted). The analysis of an accompanying visual-wavelength spectroscopy sample of ~150 spectra will be the subject of a future paper., Comment: Updated a couple of small errors
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49. Transport by gravito-inertial waves in differentially rotating stellar radiation zones
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Stéphane Mathis, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire Univers et Théories (LUTH (UMR_8102)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)
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Physics ,Angular momentum ,Stellar rotation ,Astronomy and Astrophysics ,Angular velocity ,Astrophysics ,Inertial wave ,Classical mechanics ,[SDU]Sciences of the Universe [physics] ,Space and Planetary Science ,Angular momentum of light ,Radiative transfer ,Differential rotation ,Solar rotation ,Astrophysics::Earth and Planetary Astrophysics ,[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph] - Abstract
International audience; Context: We examine the dynamics of low-frequency waves in differentially rotating stellar radiation zones, the angular velocity being taken as generally as possible depending both on radius and on latitude in stellar interiors. The associated induced transport of angular momentum, which plays a key role in the evolution of rotating stars, is derived. Aims: We focus on the wave-induced transport of angular momentum, taking into account the Coriolis acceleration in the case of strong radial and latitudinal differential rotation. We thus go beyond the ``weak differential rotation'' approximation, where rotation is almost a solid-body one plus a residual radial differential rotation. As has been shown in previous works, the Coriolis acceleration modifies such transport. Methods: We built analytically a complete formalism that allows the study of rotational transport in stellar radiation zones taking into account the wave action modified by a general strong differential rotation. Results: The different approximations possible for low-frequency waves in a differentially rotating stably stratified radiative region, namely the traditional and the JWKB approximations, are examined and discussed. The complete bidimensional structure of regular elliptic gravito-inertial waves, which verify these approximations, is derived and compared to those in the ``weak differential rotation'' case. Next, associated transport of energy and of angular momentum in the vertical and in the horizontal directions and the dynamical equations, respectively for the mean radial differential rotation and the latitudinal one, are obtained. Conclusions: The complete formalism, which takes into account low-frequency wave action, is derived and can be used for the study of secular hydrodynamics of radiative regions and of the associated mixing. The modification of waves due to general strong differential rotation and their feed-back on the angular momentum transport are treated rigourously. In a forthcoming paper (Paper II), this formalism will be applied to the case of solar differential rotation. However, the case of hyperbolic gravito-inertial waves should be carefully studied.
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- 2009
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50. Source detection using a 3D sparse representation: application to the Fermi gamma-ray space telescope
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Bo Zhang, J. Chiang, Jean-Luc Starck, Jalal M. Fadili, Seth Digel, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Equipe Image - Laboratoire GREYC - UMR6072, Groupe de Recherche en Informatique, Image et Instrumentation de Caen (GREYC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS), SLAC National Accelerator Laboratory (SLAC), Stanford University, Analyse d'Images Quantitative (AIQ), Institut Pasteur [Paris] (IP)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Normandie Université (NU)-Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU), and Institut Pasteur [Paris]-Centre National de la Recherche Scientifique (CNRS)
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Active galactic nucleus ,Astrophysics::High Energy Astrophysical Phenomena ,FOS: Physical sciences ,techniques: image processing ,Astrophysics ,01 natural sciences ,law.invention ,Telescope ,[INFO.INFO-TS]Computer Science [cs]/Signal and Image Processing ,Spitzer Space Telescope ,law ,0103 physical sciences ,Angular resolution ,Blazar ,Instrumentation and Methods for Astrophysics (astro-ph.IM) ,010303 astronomy & astrophysics ,High Energy Astrophysical Phenomena (astro-ph.HE) ,Physics ,010308 nuclear & particles physics ,Gamma ray ,Astronomy and Astrophysics ,methods: data analysis ,Thresholding ,Space and Planetary Science ,[INFO.INFO-TI]Computer Science [cs]/Image Processing [eess.IV] ,Astrophysics - Instrumentation and Methods for Astrophysics ,Astrophysics - High Energy Astrophysical Phenomena ,[SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing ,Fermi Gamma-ray Space Telescope - Abstract
The multiscale variance stabilization Transform (MSVST) has recently been proposed for Poisson data denoising. This procedure, which is nonparametric, is based on thresholding wavelet coefficients. We present in this paper an extension of the MSVST to 3D data (in fact 2D-1D data) when the third dimension is not a spatial dimension, but the wavelength, the energy, or the time. We show that the MSVST can be used for detecting and characterizing astrophysical sources of high-energy gamma rays, using realistic simulated observations with the Large Area Telescope (LAT). The LAT was launched in June 2008 on the Fermi Gamma-ray Space Telescope mission. The MSVST algorithm is very fast relative to traditional likelihood model fitting, and permits efficient detection across the time dimension and immediate estimation of spectral properties. Astrophysical sources of gamma rays, especially active galaxies, are typically quite variable, and our current work may lead to a reliable method to quickly characterize the flaring properties of newly-detected sources., Accepted. Full paper will figures available at http://jstarck.free.fr/aa08_msvst.pdf
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- 2009
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