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1. On deviations from free-radial outflow in the inner coma of comet 67P/Churyumov–Gerasimenko

Author: Olivier Groussin, Björn Davidsson, Giampiero Naletto, S. Fornasier, Cecilia Tubiana, Horst Uwe Keller, P. L. Lamy, Michael Küppers, J.F. Wu, Hans Rickman, M. A. Barucci, W-H. Ip, Ekkehard Kührt, Stubbe F. Hviid, Selina-Barbara Gerig, L. M. Lara, C. C. Su, Marco Fulle, Nilda Oklay, R. Rodrigo, Monica Lazzarin, Stefano Mottola, Jean-Baptiste Vincent, V. Da Deppo, Laurent Jorda, Jörg Knollenberg, P. J. Gutierrez, Stefano Debei, Frank Scholten, G. Cremonese, M. De Cecco, Holger Sierks, Frank Preusker, J. L. Bertaux, Cesare Barbieri, Jakob Deller, Raphael Marschall, Dennis Bodewits, J. J. Lopez Moreno, Ivano Bertini, Detlef Koschny, Nicolas Thomas, Carsten Güttler, Jessica Agarwal, Imre Tóth, Francesco Marzari, J.-R. Kramm, Swiss National Science Foundation, European Commission, Physikalisches Institut [Bern], Universität Bern [Bern] (UNIBE), Centro di Ateneo di Studi e Attività Spaziali 'Giuseppe Colombo' (CISAS), Università degli Studi di Padova = University of Padua (Unipd), Department of Astronomy [College Park], University of Maryland [College Park], University of Maryland System-University of Maryland System, Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), INAF - Osservatorio Astronomico di Trieste (OAT), Istituto Nazionale di Astrofisica (INAF), Institute of Astronomy [Taiwan] (IANCU), National Central University [Taiwan] (NCU), Institut für Geophysik und Extraterrestrische Physik [Braunschweig] (IGEP), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Operations Department (ESAC), European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA)-Agence Spatiale Européenne = European Space Agency (ESA), DLR Institut für Planetenforschung, Deutsches Zentrum für Luft- und Raumfahrt [Berlin] (DLR), Department of Mechanical Engineering [NCTU], National Chiao Tung University (NCTU), Konkoly Observatory, Research Centre for Astronomy and Earth Sciences [Budapest], Hungarian Academy of Sciences (MTA)-Hungarian Academy of Sciences (MTA), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Dipartimento di Fisica e Astronomia 'Galileo Galilei', PLANETO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), International Space Science Institute [Bern] (ISSI), European Space Research and Technology Centre (ESTEC), Agence Spatiale Européenne = European Space Agency (ESA), Space Research Centre of Polish Academy of Sciences (CBK), Polska Akademia Nauk = Polish Academy of Sciences (PAN), Department of Physics and Astronomy [Uppsala], Uppsala University, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astronomico di Padova (OAPD), Laboratory for Ultraviolet and X-ray Optical Research [Padova] (LUXOR), CNR Institute for Photonics and Nanotechnologies (IFN), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR)-National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), University of Trento [Trento], Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Universität Bern [Bern], Institute of Space Science [Taiwan], Max-Planck-Institut für Sonnensystemforschung (MPS), Max Planck Institute for Solar System Research (MPS), DLR Institute of Planetary Research, German Aerospace Center (DLR), University of Bern (UBERN), International Space Science Institute (ISSI), Centro Interdipartimentale di Studi e Attività Spaziali 'Giuseppe Colombo', Università di Padova (CISAS), Department of Astronomy, University of Maryland, Jet Propulsion Laboratory, California Institute of Technology (JPL), INAF - Osservatorio Astronomico, Via Tiepolo 11, 34014 Trieste, Italy, Graduate Institute of Astronomy, Institute for Geophysics and Extraterrestrial Physics, Technische Universität Braunschweig, Science Operations Department, European Space Astronomy Centre/ESA, P.O. Box 78, 28691 Villanueva de la Canada, Madrid, Spain, Deutsches Zentrum für Luft- und Raumfahrt (DLR), Department of Physics, National Tsing Hua University, Konkoly Observatory, Research Center for Astronomy and Earth Sciences, Max-Planck-Institut fur Sonnensystemforschung, Justus-von-Liebig-Weg, 3, 37077 Gottingen, Germany, Department of Physics and Astronomy, University of Padova, Vicolo dell'Osservatorio 3, 35122 Padova, Italy, Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), European Space Agency (ESA), Space Research Center, Polish Academy of Sciences (Warsaw), Observatoire de Paris, Université Paris sciences et lettres (PSL), CNR-IFN UOS Padova LUXOR, Università di Trento (UNITN), Instituto de Astrofisica de Andalucia, CSIC (IAA), Dipartimento di Fisica, Università di Padova, Universita degli Studi di Padova, California Institute of Technology (CALTECH)-NASA, European Space Agency (ESA)-European Space Agency (ESA), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Consiglio Nazionale delle Ricerche [Roma] (CNR)-Consiglio Nazionale delle Ricerche [Roma] (CNR), Technische Universität Braunschweig [Braunschweig], Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), IMPEC - LATMOS, Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), Polska Akademia Nauk (PAN), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), and Consejo Superior de Investigaciones Científicas [Spain] (CSIC)
Subjects: 67P/Churyumov-Gerasimenko, Brightness, 010504 meteorology & atmospheric sciences, Infrared, 67P/Churyumov–Gerasimenko, Astrophysics, Dust, Inner coma, OSIRIS, Rosetta, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Magnetosphere particle motion, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 520 Astronomy, Astronomy and Astrophysics, 620 Engineering, Particle acceleration, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Outflow, Direct simulation Monte Carlo, Astrophysics::Earth and Planetary Astrophysics, Test particle, Impact parameter, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: This article is available under the Creative Commons CC-BY-NC-ND license and permits non-commercial use of the work as published, without adaptation or alteration provided the work is fully attributed. For commercial reuse, permission must be requested below., The Optical, Spectroscopic, and Infrared Remote Imaging System (OSIRIS) onboard the European Space Agency's Rosetta spacecraft acquired images of comet 67P/Churyumov–Gerasimenko (67P) and its surrounding dust coma starting from May 2014 until September 2016. In this paper we present methods and results from analysis of OSIRIS images regarding the dust outflow in the innermost coma of 67P. The aim is to determine the global dust outflow behaviour and place constraints on physical processes affecting particles in the inner coma. We study the coma region right above the nucleus surface, spanning from the nucleus centre out to a distance of about 50 km comet centric distance (approximately 25 average comet radii). We primarily adopt an approach used by Thomas and Keller (1990) to study the dust outflow. We present the effects on azimuthally-averaged values of the dust reflectance of non-radial flow and non-point-source geometry, acceleration of dust particles, sublimation of icy dust particles after ejection from the surface, dust particle fragmentation, optical depth effects and the influence of gravitationally bound particles. All of these physical processes could modify the observed distribution of light scattered by the dust coma. In the image analysis, profiles of azimuthally averaged dust brightness as a function of impact parameter b (azimuthal average, “Ā-curve”) were fitted with a simple function that best fits the shape of our profile curves (f(b;u,v,w,z)=u/b+wb+z). The analytical fit parameters (u, v, w, z), which hold the key information about the dust outflow behaviour, were saved in a comprehensive database. Through statistical analysis of these information, we show that the spatial distribution of dust follows free-radial outflow behaviour (i.e. force-free radial outflow with constant velocity) beyond distances larger than ∼11.9 km from the comet centre, which corresponds to a relative distance of about 6 average comet radii from the comet centre. Hence, we conclude that beyond this distance, and on average, fragmentation and gravitationally bound particles are negligible processes in determining the optically scattered light distribution in the innermost coma. Closer to the nucleus we observe dust outflow behaviour that deviates from free-radial outflow. A comparison of our result profiles with numerical models using a Direct Simulation Monte Carlo (DSMC) approach with dust particle distributions calculated using a test particle approach has been used to demonstrate the influence of a complex shape and particle acceleration on the azimuthal average profiles. We demonstrate that, while other effects such as fragmentation or sublimation of dust particles cannot be ruled out, acceleration of the dust particles and effects arising from the shape of the irregular nucleus (non-point source geometry) are sufficient to explain the observed dust outflow behaviour from image data analysis. As a by-product of this work, we have calculated “Afρ” values for the 1/r regime. We found a peak in the coma activity in terms of Afρ (normalised to a phase angle of 90°) of ∼210 cm 20 days after perihelion. Furthermore, based on simplified models of particle motion within bound orbits, it is shown that limits on the total cross-sectional area of bound particles might be derived through further analysis. An example is given. © 2018 The Authors, The team from the University of Bern is supported through the Swiss National Science Foundation and through the NCCR PlanetS. The project has also received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No. 686709. This work was supported by the Swiss State Secretariat for Education, Research and Innovation (SERI) under contract number 16.0008-2. The opinions expressed and arguments employed herein do not necessarily reflect the official views of the Swiss Government.
Published: 2018
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2. EURONEAR—Recovery, follow-up and discovery of NEAs and MBAs using large field 1–2m telescopes

Author: D. Dumitru, A. Sonka, David Asher, Iulia M. Comsa, Javier Licandro, T. Badescu, A. Nedelcu, Eduardo Unda-Sanzana, C. Vancea, A. Barr, R. Toma, J. L. Ortiz, D. Vidican, Ovidiu Vaduvescu, F. Pozo, Mirel Birlan, M. Constantinescu, M. Badea, Marcel Popescu, C. Opriseanu, A. Tudorica, Isaac Newton Group of Telescopes, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Groupe Astrométrie et Planétologie (GAP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Astronomical Institute of the Romanian Academy, Bucharest, Bonn Cologne Graduate School of Physics and Astronomy, Astronomical Observatory 'Admiral Vasile Urseanu', Instituto de Astronomia, Universidad Catolica del Norte, Armagh Observatory, College Hill, Instituto de Astrofísica de Canarias (IAC), Instituto de Astrofisica de Andalucia, CSIC (IAA), Astroclubul Bucuresti, Department of Physics, University of Bucharest, Rheinische Friedrich-Wilhelms-Universität Bonn, and Faculty of Mathematics and Informatics, Babes-Bolyai University
Subjects: Earth and Planetary Astrophysics (astro-ph.EP), Orbital elements, Physics, Near-Earth object, media_common.quotation_subject, FOS: Physical sciences, Astronomy, Astronomy and Astrophysics, Astrometry, Astrophysics, law.invention, Telescope, Space and Planetary Science, Asteroid, Sky, law, Evaluation methods, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics, media_common
Abstract: We report on the follow-up and recovery of 100 program NEAs, PHAs and VIs using the ESO/MPG 2.2m, Swope 1m and INT 2.5m telescopes equipped with large field cameras. The 127 fields observed during 11 nights covered 29 square degrees. Using these data, we present the incidental survey work which includes 558 known MBAs and 628 unknown moving objects mostly consistent with MBAs from which 58 objects became official discoveries. We planned the runs using six criteria and four servers which focus mostly on faint and poorly observed objects in need of confirmation, follow-up and recovery. We followed 62 faint NEAs within one month after discovery and we recovered 10 faint NEAs having big uncertainties at their second or later opposition. Using the INT we eliminated 4 PHA candidates and VIs. We observed in total 1,286 moving objects and we reported more than 10,000 positions. All data were reduced by the members of our network in a team effort, and reported promptly to the MPC. The positions of the program NEAs were published in 27 MPC and MPEC references and used to improve their orbits. The O-C residuals for known MBAs and program NEAs are smallest for the ESO/MPG and Swope and about four times larger for the INT whose field is more distorted. The incidental survey allowed us to study statistics of the MBA and NEA populations observable today with 1--2m facilities. We calculate preliminary orbits for all unknown objects, classifying them as official discoveries, later identifications and unknown outstanding objects. The orbital elements a, e, i calculated by FIND_ORB software for the official discoveries and later identified objects are very similar with the published elements which take into account longer observational arcs; thus preliminary orbits were used in statistics for the whole unknown dataset. (CONTINUED), Accepted in Planetary and Space Science (Aug 2011)
Published: 2011
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3. Low-amplitude variations detected by CoRoT in the B8IIIe star HD 175869

Author: M. Auvergne, A. L. Huat, B. de Batz, O. Thizy L. Andrade, Y. Frémat, J. Suso, Eduardo Janot-Pacheco, T. Semaan, Juan Gutiérrez-Soto, R. Garrido, Michele Floquet, R. Samadi, Marcelo Emilio, Coralie Neiner, Juan Fabregat, F. Espinosa Lara, B. Leroy, Anne-Marie Hubert, P. D. Diago, Christophe Martayan, S. Chaintreuil, C. Catala, Eric Michel, Galaxies, Etoiles, Physique, Instrumentation (GEPI), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Physique stellaire et galactique, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-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 Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Instituto de Astrofisica de Andalucia, CSIC (IAA), Universitat de València (UV), Observatoire Royal de Belgique (ORB), Departamento de Geociências, Universidade Estadual de Ponta Grossa, Shelyak Instruments, and Departamento de Astronomia Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Universidade de São Paulo
Subjects: Physics, Photosphere, Be star, Astronomy, Astronomy and Astrophysics, Context (language use), Astrophysics, Light curve, Stars, Amplitude, Space and Planetary Science, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Emission spectrum, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Line (formation)
Abstract: International audience; Context: The origin of the short-term variability in Be stars remains a matter of controversy. Pulsations and rotational modulation are the components of the favored hypothesis. Aims: We present our analysis of CoRoT data of the B8IIIe star HD 175869 observed during the first short run in the center direction (SRC1). Methods: We review both the instrumental effects visible in the CoRoT light curve and the analysis methods used by the CoRoT Be team. We applied these methods to the CoRoT light curve of the star HD 175869. A search for line-profile variations in the spectroscopic data was also performed. We also searched for a magnetic field, by applying the LSD technique to spectropolarimetric data. Results: The light curve exhibits low-amplitude variations of the order of 300 mumag with a double wave shape. A frequency within the range determined for the rotational frequency and 6 of its harmonics are detected. The main frequency and its first harmonic exhibit amplitude variations of a few days. Other significant frequencies of low-amplitude from 25 to a few mumag are also found. The analysis of line profiles from ground-based spectroscopic data does not detect any variation. In addition, no Zeeman signature was found. Conclusions: Inhomogeneities caused by stellar activity in or just above the photosphere are proposed to produce the photometric variability detected by CoRoT in the Be star HD 175869. The hypothesis that non-radial pulsations are the origin of these variations cannot be excluded.
Published: 2009
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4. HD 50844: a new look atδScuti stars from CoRoT space photometry

Author: L. Mantegazza, K. Uytterhoeven, Eric Michel, M. Auvergne, Frédéric Baudin, C. Catala, E. Rodriguez, Ennio Poretti, R. Samadi, Juan Carlos Suárez, Susana Martín-Ruiz, Monica Rainer, M. Alvarez, Annie Baglin, Laure Lefèvre, Emese Plachy, R. Garrido, Péter Pápics, Philippe Mathias, M. Paparó, E. Niemczura, W. Zima, A. Moya, Pedro J. Amado, INAF-Osservatorio Astronomico di Brera (INAF-OAB), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Instituto de Astrofisica de Andalucia, CSIC (IAA), Astronomical Institute, University of Wroclaw, Instituut voor Sterrenkunde, Katholieke Universiteit Leuven, Institut d'astrophysique spatiale (IAS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Observatorio Astronómico Nacional, Instituto de Astronomía, Universidad Nacional Autónoma de México, Laboratoire Hippolyte Fizeau (FIZEAU), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), and Konkoly Observatory, Research Center for Astronomy and Earth Sciences
Subjects: Physics, Frequency analysis, Flux, Astronomy, Astronomy and Astrophysics, Context (language use), Astrophysics, Light curve, Spectral line, law.invention, Photometry (optics), Stars, Amplitude, [SDU]Sciences of the Universe [physics], Space and Planetary Science, law, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: International audience; Context: Aims: This work presents the results obtained by CoRoT on HD 50844, the only delta Sct star observed in the CoRoT initial run (57.6 d). The aim of these CoRoT observations was to investigate and characterize for the first time the pulsational behaviour of a delta Sct star, when observed at a level of precision and with a much better duty cycle than from the ground. Methods: The 140 016 datapoints were analysed using independent approaches (SigSpec software and different iterative sine-wave fittings) and several checks performed (splitting of the timeseries in different subsets, investigation of the residual light curves and spectra). A level of 10-5 mag was reached in the amplitude spectra of the CoRoT timeseries. The space monitoring was complemented by ground-based high-resolution spectroscopy, which allowed the mode identification of 30 terms. Results: The frequency analysis of the CoRoT timeseries revealed hundreds of terms in the frequency range 0-30 d-1. All the cross-checks confirmed this new result. The initial guess that delta Sct stars have a very rich frequency content is confirmed. The spectroscopic mode identification gives theoretical support since very high-degree modes (up to l=14) are identified. We also prove that cancellation effects are not sufficient in removing the flux variations associated to these modes at the noise level of the CoRoT measurements. The ground-based observations indicate that HD 50844 is an evolved star that is slightly underabundant in heavy elements, located on the Terminal Age Main Sequence. Probably due to this unfavourable evolutionary status, no clear regular distribution is observed in the frequency set. The predominant term (f_1=6.92 d-1) has been identified as the fundamental radial mode combining ground-based photometric and spectroscopic data. Conclusions
Published: 2009
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5. Stellar population constraints on the dark matter content and origin of ultra-compact dwarf galaxies★

Author: Igor Chilingarian, Gilles Bergond, V. Cayatte, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Shternberg State Institute of Astronomy (SSIA), Laboratoire Univers et Théories (LUTH (UMR_8102)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), and Instituto de Astrofisica de Andalucia, CSIC (IAA)
Subjects: Physics, Initial mass function, Stellar mass, Stellar population, Milky Way, Astrophysics (astro-ph), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Galaxy, Space and Planetary Science, Globular cluster, Elliptical galaxy, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics::Galaxy Astrophysics, Dwarf galaxy
Abstract: We analyse intermediate-resolution VLT FLAMES/Giraffe spectra of six ultra-compact dwarf (UCD) galaxies in the Fornax cluster. We obtained velocity dispersions and stellar population properties by full spectral fitting against PEGASE.HR models. Objects span a large range of metallicities (-0.95 to -0.23 dex), 4 of them are older than 8 Gyr. Comparison of the stellar and dynamical masses suggests that UCDs have little dark matter at best. For one object, UCD3, the Salpeter initial mass function (IMF) results in the stellar mass significantly exceeding the dynamical one, whereas for the Kroupa IMF the values coincide. Although, this object may have peculiar dynamics or/and stellar populations, the Kroupa IMF seems more realistic. We find that UCDs lie well above the metallicity-luminosity relation of early-type galaxies. The same behaviour is demonstrated by some of the massive Milky Way globular clusters, known to contain composite stellar populations. Our results support two following UCD formation scenarii: (1) tidal stripping of nucleated dwarf elliptical galaxies; (2) formation of tidal superclusters in galaxy mergers. We also discuss some of the alternative channels of the UCD formation binding them to globular clusters., Comment: accepted to MNRAS, 7 pages, 4 figures, 3 tables
Published: 2008
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6. A procedure for modelling asymptotic g-mode pulsators: The case of γ Doradus stars

Author: Andrés Moya, Pedro J. Amado, Marc-Antoine Dupret, Cristina Rodríguez-López, J. C. Suárez, Susana Martín-Ruiz, R. Garrido, E. Rodríguez, A. Grigahcène, Instituto de Astrofisica de Andalucia, CSIC (IAA), Centre de Recherche en Astronomie Astrophysique et Géophysique - Observatoire d'Alger (CRAAG), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, Stars, T Tauri star, Space and Planetary Science, Frequency ratio, Mode (statistics), Astrophysics::Solar and Stellar Astrophysics, Applied mathematics, Astronomy and Astrophysics, Astrophysics, Star (graph theory), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Asteroseismology
Abstract: Mode identification is one of the first and main problems we encounter in trying to develop the complete potential of asteroseismology. In the particular case of g-mode pulsators, this is still an unsolved problem, from both the observational and theoretical points of view. Nevertheless, in recent years, some observational and theoretical efforts have been made to find a solution. In this work we use the latest theoretical and computational tools to understand asymptotic g-mode pulsators: 1) the Frequency Ratio Method, and 2) Time Dependent Convection. With these tools, a self-consistent procedure for mode identification and modelling of these g-mode pulsators can be constructed. This procedure is illustrated using observational information available for the γ Doradus star 9Aurigae. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Published: 2008
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7. Fueling the central engine of radio galaxies

Author: Jeremy Lim, Stephane Leon, Santiago García-Burillo, Asunción Fuente, Antonio Usero, Roberto Neri, Francoise Combes, Observatorio Astronomico Nacional, Madrid, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Galaxies et cosmologie, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), Instituto de Astrofisica de Andalucia, CSIC (IAA), and Institute of Astronomy and Astrophysics, Academia Sinica
Subjects: Physics, Space and Planetary Science, Radio galaxy, Astrophysics (astro-ph), FOS: Physical sciences, Plateau de Bure Interferometer, Astronomy and Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics::Galaxy Astrophysics
Abstract: We report the detection of a massive (M(gas) > 5x10^9 Msun) molecular/dusty disk of 1.4kpc-size fueling the central engine of the Compact Symmetric Object (CSO) 4C31.04 based on high-resolution (0.5''--1.2'') observations done with the IRAM Plateau de Bure interferometer (PdBI). These observations allow for the first time to detect and map the continuum emission from dust at 218GHz in the disk of a CSO. The case for a massive disk is confirmed by the detection of strong HCO+(1--0) line emission and absorption. The molecular gas mass of 4C31.04 is in the range 0.5x10^10--5x10^10Msun. While the distribution and kinematics of the gas correspond roughly to those of a rotating disk, we find evidence of distortions and non-circular motions suggesting that the disk is not in a dynamically relaxed state. We discuss the implications of these results for the general understanding of the evolution of radio galaxies., 5 pages, 3 figures, Accepted (25/04/2007) in A&A Letters
Published: 2007
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8. Pluto's atmosphere from stellar occultations in 2012 and 2013

Author: A. Dias-Oliveira, B. Sicardy, E. Lellouch, R. Vieira-Martins, M. Assafin, J. I. B. Camargo, F. Braga-Ribas, A. R. Gomes-Júnior, G. Benedetti-Rossi, F. Colas, A. Decock, A. Doressoundiram, C. Dumas, M. Emilio, J. Fabrega Polleri, R. Gil-Hutton, M. Gillon, J. H. Girard, G. K. T. Hau, V. D. Ivanov, E. Jehin, J. Lecacheux, R. Leiva, C. Lopez-Sisterna, L. Mancini, J. Manfroid, A. Maury, E. Meza, N. Morales, L. Nagy, C. Opitom, J. L. Ortiz, J. Pollock, F. Roques, C. Snodgrass, J. F. Soulier, A. Thirouin, L. Vanzi, T. Widemann, D. E. Reichart, A. P. LaCluyze, J. B. Haislip, K. M. Ivarsen, M. Dominik, U. Jørgensen, J. Skottfelt, Observatório Nacional/MCTI, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Observatório do Valongo, Universidade Federal do Rio de Janeiro, UTFPR, Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Astéroïdes, comètes, météores et éphémérides (ACME), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, ESO, UEPG, Observatorio Panemno, CASLEO-CONICET, Universite de Liege, PUC, Universidade Nacional de San Juan, Max-Planck-Institut für Astronomie (MPIA), S.P.A.C.E, Instituto de Astrofisica de Andalucia, CSIC (IAA), Appalachian State University, CEPSAR, The Open University, Association T60, Observatoire Midi-Pyrénées, 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)-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, Lowell Observatory, Flagstaff, University of North Carolina, School of Chemistry, University of St Andrews, University of Copenhagen, Observatorio Nacional [Rio de Janeiro], Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Observatório Nacional/MCT, PSL Research University (PSL)-PSL Research University (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Observatório do Valongo/UFRJ [Rio de Janeiro], Universidade Federal do Rio de Janeiro [Rio de Janeiro] (UFRJ), Universidade Estadual de Ponta Grossa, Universidade Estadual de Ponta Grossa - State University of Ponta Grossa (UEPG), Universidad Nacional de San Juan (UNSJ), Arctic and Antarctic Research Institute (AARI), Russian Federal Service for Hydrometeorology and Environmental Monitoring (Roshydromet), European Southern Observatory (ESO), Southwest Research Institute [Boulder] (SwRI), Centre de Nanosciences et Nanotechnologies (C2N (UMR_9001)), Université Paris-Sud - Paris 11 (UP11)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut d'Astrophysique et de Géophysique [Liège], Université de Liège, 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), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Department of Physics and Astronomy [Boone], University of North Carolina System (UNC)-University of North Carolina System (UNC), School of Physical Sciences [Milton Keynes], The Open University [Milton Keynes] (OU), Lowell Observatory [Flagstaff], Dynamiques patrimoniales et culturelles (DYPAC), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Centre National de la Recherche Scientifique (CNRS)-Université de Lille-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Universidade Federal do Rio de Janeiro (UFRJ), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Faculty of Science, Technology, Engineering and Mathematics [Milton Keynes], The Open University [Milton Keynes] (OU)-The Open University [Milton Keynes] (OU), Universidad Nacional de San Juan [Argentine] (UNSJ), 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), The Royal Society, and University of St Andrews. School of Physics and Astronomy
Subjects: 010504 meteorology & atmospheric sciences, NDAS, FOS: Physical sciences, Astrophysics, 01 natural sciences, Mesosphere, Troposphere, Atmosphere, Settore FIS/05 - Astronomia e Astrofisica, 0103 physical sciences, QB Astronomy, observational [Methods], data analysis [Methods], 010303 astronomy & astrophysics, Stratosphere, physical evolution [Planets and satellites], QC, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, QB, Physics, Earth and Planetary Astrophysics (astro-ph.EP), [PHYS]Physics [physics], photometric [Techniques], Center (category theory), Astronomy and Astrophysics, Radius, Pluto, Temperature gradient, QC Physics, 13. Climate action, Space and Planetary Science, terrestrial planets [Planets and satellites], atmospheres [Planets and satellites], [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics
Abstract: We analyze two multi-chord stellar occultations by Pluto observed on July 18th, 2012 and May 4th, 2013, and monitored respectively from five and six sites. They provide a total of fifteen light-curves, twelve of them being used for a simultaneous fit that uses a unique temperature profile, assuming a clear (no-haze) and pure N_2 atmosphere, but allowing for a possible pressure variation between the two dates. We find a solution that fits satisfactorily (i.e. within the noise level) all the twelve light-curves, providing atmospheric constraints between ~1,190 km (pressure ~ 11 \mubar) and ~ 1,450 km (pressure ~0.1 \mubar) from Pluto's center. Our main results are: (1) the best-fitting temperature profile shows a stratosphere with strong positive gradient between 1,190 km (at 36 K, 11 \mubar) and r = 1,215 km (6.0 \mubar), where a temperature maximum of 110 K is reached; above it is a mesosphere with negative thermal gradient of -0.2 K/km up to ~ 1,390 km (0.25 \mubar), where, the mesosphere connects itself to a more isothermal upper branch around 81 K; (2) the pressure shows a small (6 %) but significant increase (6-\sigma level) between the two dates; (3) without troposphere, Pluto's radius is found to be R_P = 1,190 +/- 5km. Allowing for a troposphere, R_P is constrained to lie between 1,168 and 1,195 km; (4) the currently measured CO abundance is too small to explain the mesospheric negative thermal gradient. Cooling by HCN is possible, but only if this species is largely saturated; Alternative explanations like zonal winds or vertical compositional variations of the atmosphere are unable to explain the observed mesospheric trend., Comment: 41 pages, 13 figures, 4 tables
Published: 2015
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9. The asymptotic representation of higher-order g$\mathsf{^+}$-modes in stars with a convective core

Author: Paul Smeyers, Andrés Moya, Instituut voor Sterrenkunde, Katholieke Universiteit Leuven, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), and Instituto de Astrofisica de Andalucia, CSIC (IAA)
Subjects: Physics, Surface (mathematics), Asymptotic analysis, Astronomy and Astrophysics, Astrophysics, Radiation zone, Displacement (vector), Stars, Classical mechanics, [SDU]Sciences of the Universe [physics], Space and Planetary Science, Radiative transfer, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Circular symmetry, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Mathematical physics, Envelope (waves)
Abstract: International audience; Aims:A first-order asymptotic representation of higher-order non-radial g^+-modes in spherically symmetric stars with a convective core is constructed from the full fourth-order system of governing equations. Stars are considered that, besides their convective core, also contain a radiative envelope, or both an intermediate radiative zone and a convective envelope. At the same time, the earlier asymptotic theory of Willems et al. (1997, A&A, 318, 99) relative to stars consisting of a convective core and a radiative envelope is made more transparent. Methods: As in the asymptotic theory of Smeyers (2006, A&A, 451, 223) for low-degree, higher-order p-modes, two-variable expansion procedures and boundary-layer theory are applied to the fourth-order system of differential equations established by Pekeris (1938, ApJ, 88, 189). Results: Eigenfrequency equations are derived in terms of the radial order n of the g^+-mode. The first n - 1 nodes of the radial component of the Lagrangian displacement coincide with the n - 1 nodes of the divergence of the Lagrangian displacement, and are situated in the radiative envelope or in the intermediate radiative zone according to the type of star considered. The radial displacement displays an nth node near the surface. In stars containing an intermediate radiative zone and a convective envelope, the nth node is situated in the envelope. Conclusions: .As well as for higher-order p-modes of spherically symmetric stars, the divergence of the Lagrangian displacement plays a basic role in the development of the asymptotic theory.
Published: 2006
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10. On the discovery of CO nighttime emissions on Titan by Cassini/VIMS: Derived stratospheric abundances and geological implications

Author: Kevin H. Baines, Bonnie J. Buratti, Miguel Lopez-Valverde, Robert H. Brown, Philip D. Nicholson, Thomas W. Momary, Roger N. Clark, Sushil K. Atreya, Christophe Sotin, Pierre Drossart, Jet Propulsion Laboratory, California Institute of Technology (JPL), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Instituto de Astrofisica de Andalucia, CSIC (IAA), Department of Atmospheric, Oceanic and Space Sciences, University of Michigan, Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Lunar and Planetary Laboratory [University of Arizona] (LPL), University of Arizona, US Geological Survey, Denver, and Department of Astronomy, Cornell University
Subjects: Physics, 010504 meteorology & atmospheric sciences, Airglow, Astronomy and Astrophysics, Atmospheric sciences, 01 natural sciences, 7. Clean energy, Atmosphere, symbols.namesake, 13. Climate action, Space and Planetary Science, Stratopause, Atmospheric chemistry, 0103 physical sciences, Mixing ratio, symbols, Atmosphere of Titan, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Titan (rocket family), 010303 astronomy & astrophysics, Stratosphere, 0105 earth and related environmental sciences
Abstract: International audience; We present a quantitative analysis of CO thermal emissions discovered on the nightside of Titan by Baines et al. [2005. The atmospheres of Saturn and Titan in the near-infrared: First results of Cassini/VIMS. Earth, Moon, and Planets, 96, 119-147]. in Cassini/VIMS spectral imagery. We identify these emission features as the P and R branches of the 1-0 vibrational band of carbon monoxide (CO) near 4.65 mum. For CH 3D, the prominent Q branch of the nu 2 fundamental band of CH 3D near 4.55 mum is apparent. CO 2 emissions from the strong v3 vibrational band are virtually absent, indicating a CO 2 abundance several orders of magnitude less than CO, in agreement with previous investigations. Analysis of CO emission spectra obtained over a variety of altitudes on Titan's nightside limb indicates that the stratospheric abundance of CO is 32±15 ppm, and together with other recent determinations, suggests a vertical distribution of CO nearly constant at this value from the surface throughout the troposphere to at least the stratopause near 300 km altitude. The corresponding total atmospheric content of CO in Titan is ˜2.9±1.5×10 14 kg. Given the long lifetime of CO in the oxygen-poor Titan atmosphere (˜0.5-1.0 Gyr), we find a mean CO atmospheric production rate of 6±3×10 5 kg yr -1. Given the lack of primordial heavy noble gases observed by Huygens [Niemann et al., 2005. The abundances of constituents of Titan's atmosphere from the GCMS on the Huygens probe. Nature, 438, 779-784], the primary source of atmospheric CO is likely surface emissions. The implied CO/CH 4 mixing ratio of near-surface material is 1.8±0.9×10 -4, based on an average methane surface emission rate over the past 0.5 Gyr of 1.3×10 -13 gm cm -2 s -1 as required to balance hydrocarbon haze production via methane photolysis [Wilson and Atreya, 2004. Current state of modeling the photochemistry of Titan's mutually dependent atmosphere and ionosphere. J. Geophys. Res. 109, E06002 Doi:10.1029/2003JE002181]. This low CO/CH 4 ratio is much lower than expected for the sub-nebular formation region of Titan and supports the hypothesis [e.g., Atreya et al., 2005. Methane on Titan: photochemical-meteorological-hydrogeochemical cycle. Bull. Am. Astron. Soc. 37, 735] that the conversion of primordial CO and other carbon-bearing materials into CH 4-enriched clathrate-hydrates occurs within the deep interior of Titan via the release of hydrogen through the serpentinization process followed by Fischer-Tropsch catalysis. The time-averaged predicted emission rate of methane-rich surface materials is ˜0.02 km 3 yr -1, a value significantly lower than the rate of silicate lava production for the Earth and Venus, but nonetheless indicative of significant active geological processes reshaping the surface of Titan.
Published: 2006
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11. A comprehensive asteroseismic modelling of the high-amplitude δ Scuti star RV Arietis

Author: A. Moya, Juan Carlos Suárez, Ricard Casas, R. Garrido, Instituto de Astrofisica de Andalucia, CSIC (IAA), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Oscillations, Rotation, Variable stars, Overtone, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Star (graph theory), Fundamental parameters, Astrophysics::Solar and Stellar Astrophysics, Adiabatic process, Astrophysics::Galaxy Astrophysics, Physics, High amplitude, Oscillation, Astrophysics (astro-ph), Interiors, Astrophysics::Instrumentation and Methods for Astrophysics, Delta Scuti, RV Arietis, Mode (statistics), Astronomy and Astrophysics, Effective temperature, Stars, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: Reproduced with permission from Astronomy & Astrophysics, © ESO., We present a comprehensive asteroseismic study of the double-mode high-amplitude $\delta$ Scuti star HD 187642 ( RV Ari ). The modelling includes some of the most recent techniques: 1) effects of rotation on both equilibrium models and adiabatic oscillation spectrum, 2) non-adiabatic study of radial and non-radial modes, 3) relationship between the fundamental radial mode and the first overtone in the framework of Petersen diagrams. The analysis reveals that two of the observed frequencies are very probably identified as the fundamental and first overtone radial modes. Analysis of the colour index variations, together with theoretical non-adiabatic calculations, points to models in the range of [7065, 7245] K in effective temperature and of [1190, 1270] Myr in stellar age. These values were found to be compatible with those obtained using the three other asteroseismic techniques., This work was partially financed by the Spanish "Plan Nacional del Espacio'', under project ESP2004-03855-C03-01. J.C.S. acknowledges the financial support of the European Marie Curie action MERG-CT-2004-513610 and the Spanish "Consejería de Innovación, Ciencia y Empresa" from the "Junta de Andalucía" local government.
Published: 2006
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12. The frequency ratio method and the new multiperiodicγ Doradus star HD 218427

Author: E. Rodríguez, M. J. Lopez-Gonzalez, Pedro J. Amado, E. Poretti, A. Grigahcène, Andrés Moya, V. Costa, J. C. Suárez, M. A. Dupret, Instituto de Astrofisica de Andalucia, CSIC (IAA), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Astronomie du LESIA, 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)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, INAF-Osservatorio Astronomico di Brera (INAF-OAB), and Centre de Recherche en Astronomie Astrophysique et Géophysique - Observatoire d'Alger (CRAAG)
Subjects: Physics, Frequency analysis, Astronomy and Astrophysics, Astrophysics, Star (graph theory), Lambda, Quantum number, Instability, law.invention, Stars, Space and Planetary Science, law, Excited state, Astrophysics::Solar and Stellar Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Multiplet, Astrophysics::Galaxy Astrophysics
Abstract: International audience; Oscillations of gamma Dor-type were discovered in the star HD 218427 through simultaneous uvby photometric observations carried out in the year 2003. A few Hbeta-Crawford measurements were also collected for calibration purposes and they locate this star well inside the gamma Dor instability region. We find HD 218427 to be deficient in metals, similar to other well-defined gamma Dor stars, and discuss the possibility that it has a lambda Boo nature. We carried out frequency analysis for different filters, including the combined "vby" filter, and five frequencies were found as significant with periods ranging between 0.3 and 0.8 days. The recently-developed frequency ratio method is used in order to identify the excited modes. The results are consistent with an l=2 identification for all the modes and with high radial quantum numbers (n˜40) for the three main observed periodicities. The possibility of multiplet structures is also discussed. However, no consistency is found when using the time-dependent convection treatment to discriminate modes. This disagreement can be due to the large rotation velocity taking place in HD 218427 and, consequently, the significant coupling between the modes.
Published: 2006
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13. Carbon monoxide fluorescence from Titan's atmosphere

Author: Miguel Lopez-Valverde, Emmanuel Lellouch, Athena Coustenis, Instituto de Astrofisica de Andalucia, CSIC (IAA), Observatoire de Paris, Université Paris sciences et lettres (PSL), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-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 Paris Cité (UPCité)
Subjects: Physics, Meteorology, Spectrometer, Astronomy and Astrophysics, Atmospheric sciences, Troposphere, symbols.namesake, chemistry.chemical_compound, chemistry, Space and Planetary Science, symbols, Mixing ratio, Radiative transfer, Emission spectrum, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Titan (rocket family), Stratosphere, Carbon monoxide
Abstract: International audience; We report on the discovery of emissions due to carbon monoxide from Titan's atmosphere, from mid-infrared observations with the ISAAC spectrometer at the Very Large Telescope and covering the 4.50-4.85 mum range. We detected about 45 emission lines coinciding with CO ro-vibrational lines, including CO(1-0) (P18 to R11) and CO(2-1) (P11 to R11). We show that these emissions cannot be generated thermally but occur in non-LTE conditions, due to radiative de-excitation from the v=1 and v=2 CO levels after excitation at 4.7 and 2.3 mum by solar radiation. A complete fluorescence model is then developed, allowing to compute the state populations of the two most abundant CO isotopes and N 2(1). It includes absorption by CO and CH 4, and vibrational-thermal and vibrational-vibrational collisional exchanges with CO, N 2, CH 4, and H 2. Emerging radiances at the top of the atmosphere are evaluated with a line-by-line code and compared to observations. Contribution functions show that the CO emissions sound Titan's stratosphere: while the (1-0) lines generally probe two layers, located respectively at 100-250 km and 300-550 km, the (2-1) lines are sensitive to the intermediate layer at 150-300 km. A sensitivity study is performed to establish the effect of the main model parameters (temperature profile, collisional scenario, and CO stratospheric abundance) on the results. Models reproduce the essential structure of the observed emissions. The (1-0) fundamental band is generally well fit with a nominal CO mixing ratio of 32 ppm---as inferred in the troposphere from observations at 4.80-5.10 mum (Lellouch et al., 2003, Icarus 162, 126-143). However, this band is only weakly dependent on the CO abundance, and given temperature and collisional scenario uncertainties, it constrains the CO stratospheric mixing ratio only to within a factor of ˜3. In addition, the nominal model with 32 ppm CO underestimates the first hot (2-1) transition by approximately a factor of 2. This discrepancy can be resolved by a combined adjustment of collisional rates and an increased CO stratospheric ratio of 60 ppm, consistent with the determination of Gurwell and Muhleman (2000, Icarus 145, 653-656). In contrast, the CO vertical profile suggested by Hidayat et al. (1998, Icarus 133, 109-133), strongly depleted above 200 km, cannot match the data for any realistic collisional scenario, and is therefore not supported by our results.
Published: 2005
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14. Molecular and ionized gas in the tidal tail in Stephan's Quintet

Author: Stephane Leon, Elias Brinks, Jonathan Braine, Vassilis Charmandaris, Pierre-Alain Duc, Ute Lisenfeld, Instituto de Astrofisica de Andalucia, CSIC (IAA), Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Instituto Nacional de Astrofísica Óptica y Electrónica (INAOE), Department of Astronomy, Cornell University, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), and Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS)
Subjects: Intergalactic star, Interactions, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Clusters, Astrophysics::Solar and Stellar Astrophysics, Tidal tail, ISM, Astrophysics::Galaxy Astrophysics, Intergalactic medium, Dwarf galaxy, Physics, Spiral galaxy, Star formation, Astrophysics (astro-ph), Astronomy and Astrophysics, Molecules, Galaxies, Galaxy, Dust lane, [SDU]Sciences of the Universe [physics], Space and Planetary Science, Stephan's Quintet, Intergalactic travel, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: We have mapped with the IRAM interferometer at Plateau de Bure (PdBI) the 12CO emission towards intergalactic star forming regions located in the tidal tail stemming from NGC7319, in the Stephan's Quintet compact group of galaxies. The 13CO emission of the same region was observed with the IRAM 30m telescope and optical spectroscopy of several HII regions in the area were obtained with the Calar Alto 3.5m telescope. We recovered with the interferometer about 50% of the CO(1-0) total emission that had been earlier measured with single dish observations. We find two main areas of CO emission: (i) an elongated region towards the area known as SQ B where a Tidal Dwarf Galaxy could currently be forming (ii) a barely resolved area at the tip of the optical tidal arm. Both regions follow dust lanes visible on HST images and their CO peak coincides spatially exactly with the maximum of the Halpha line emission. In SQ B, there is furthermore very good kinematical agreement between the CO, Halpha and HI components. We conclude from these coincidences that the gaseous matter found in quantities in the area is physically associated to the optical tidal tail and thus that the intergalactic atomic hydrogen there was expelled from NGC7319. Furthermore, the relatively high oxygen abundances (about solar) estimated from the optical spectra of the HII regions imply that the gas feeding the star formation originated from the inner regions of the parent galaxy. In SQ B, we derive from different tracers a star formation rate of 0.5 \msun/yr. The inferred molecular gas consumption time of 0.5 Gyr lies in the range of values found for spiral and starburst galaxies. On the other hand, the ratio of 12CO/13CO>25 is much higher than the values found in disks of spiral galaxies. A relatively low opacity for the 12CO gas is the most likely reason., Accepted by A&A, 10 pages, 7 figures, a version with high resolution figures can be obtained from http://www.ugr.es/~ute/1330.pdf
Published: 2004
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15. Non-confirmation of reported $\ion{H}{I}$ clouds without optical counterparts in the Hercules cluster

Author: P. Papaderos, C. Balkowski, José M. Vílchez, V. Cayatte, Trinh X. Thuan, John M. Dickey, W. van Driel, H. Hernández, Karen O'Neil, Pierre-Alain Duc, Jorge Iglesias-Páramo, Galaxies, Etoiles, Physique, Instrumentation (GEPI), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Physique des Galaxies et Cosmologie, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-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 Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Arecibo Observatory, Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée (DAPNIA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Department of Astronomy, University of Minnesota, Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Sternwarte Weinheim, Instituto de Astrofisica de Andalucia, CSIC (IAA), and Astronomy Department, University of Virginia, Charlottesville
Subjects: Physics, Gregorian telescope, Galactic astronomy, Continuum (measurement), 010308 nuclear & particles physics, media_common.quotation_subject, Astrophysics (astro-ph), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, general, clusters, individual, Hercules cluster, galaxies, ISM, radio lines, 01 natural sciences, law.invention, Space and Planetary Science, law, Sky, 0103 physical sciences, Surface brightness, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, media_common
Abstract: 21 cm HI line observations were made with the Arecibo Gregorian telescope of 9 HI clouds in the Hercules Cluster which were reported as tenative detections in a VLA HI study of the cluster (Dickey 1997) and for which our deep CCD imaging failed to find any optical counterparts. No sensitive observations could be made of one of these (sw-174) due to the presence of a close-by strong continuum source. The other 8 tentative HI detections were not reconfirmed by the Arecibo HI measurements. The CCD images did reveal faint, low surface brightness counterparts near the centres of two other VLA HI sources invisible on the Palomar Sky Survey, sw-103 and sw-194., Comment: 7 pages, accepted for Astronomy and Astrophysics on 8 Nov. 2002; new references added on 23 Dec. 2002
Published: 2003
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16. Galaxy clusters in the SDSS Stripe 82 based on photometric redshifts

Author: C. Adami, S. Maurogordato, Melville P. Ulmer, Ali Takey, Florence Durret, Nicolas Martinet, N. Scepi, J. Hao, Isabel Márquez, T. Sauvaget, E. Bertin, National Science Foundation (US), Department of Energy (US), University of Arizona, Brookhaven National Laboratory (US), Carnegie Mellon University, University of Florida, Harvard University, Instituto de Astrofísica de Canarias, Johns Hopkins University, Lawrence Berkeley National Laboratory, Max Planck Institute for Astrophysics, Max Planck Institute for extraterrestrial Physics, New Mexico State University, New York University, The Ohio State University, Pennsylvania State University, University of Portsmouth, Princeton University, University of Tokyo, University of Utah, Vanderbilt University, University of Virginia, University of Washington, Yale University, Ministerio de Economía y Competitividad (España), Junta de Andalucía, Alfred P. Sloan Foundation, Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Center for Particle Astrophysics, Fermi National Accelerator Laboratory, Batavia, Instituto de Astrofisica de Andalucia, CSIC (IAA), Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA), Galaxies, Etoiles, Physique, Instrumentation (GEPI), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Department of Physics and Astronomy, Northwestern University, Evanston, École normale supérieure - Cachan (ENS Cachan), National Research Institute of Astronomy and Geophysics (NRIAG), 11421 Helwan, Cairo, Egypt, Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), Laboratoire Interdisciplinaire de Physique [Saint Martin d’Hères] (LIPhy), Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), Tsinghua University [Beijing] (THU), Institut Régional de Médecine Physique et de Réadaptation Louis Pierquin [Nancy] (IRR Louis Pierquin), 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, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), NWU, Dearborn Observatory (NWU), Northwestern University Department of Physics and Astronomy, Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, and COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Galaxies: fundamental parameters, Cosmology and Nongalactic Astrophysics (astro-ph.CO), luminosity function, mass function [Galaxies], FOS: Physical sciences, Context (language use), Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, clusters: general [Galaxies], 01 natural sciences, Cosmology, Luminosity, 0103 physical sciences, Cluster (physics), 010303 astronomy & astrophysics, Galaxy cluster, Astrophysics::Galaxy Astrophysics, Photometric redshift, Physics, 010308 nuclear & particles physics, 4. Education, Galaxies: luminosity function, mass function, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Galaxy, Redshift, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), fundamental parameters [Galaxies], Galaxies: clusters: general, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract: © ESO 2015. Context. The discovery of new galaxy clusters is important for two reasons. First, clusters are interesting per se, since their detailed analysis allows us to understand how galaxies form and evolve in various environments and second, they play an important part in cosmology because their number as a function of redshift gives constraints on cosmological parameters. Aims. We have searched for galaxy clusters in the Stripe 82 region of the Sloan Digital Sky Survey, and analysed various properties of the cluster galaxies. Methods. Based on a recent photometric redshift (hereafter photo-z) galaxy catalogue, we built a cluster catalogue by applying the Adami & MAzure Cluster FInder (AMACFI). Extensive tests were made to fine-tune the AMACFI parameters and make the cluster detection as reliable as possible. The same method was applied to the Millennium simulation to estimate our detection efficiency and the approximate masses of the detected clusters. Considering all the cluster galaxies (i.e. within a 1 Mpc radius of the cluster to which they belong and with a photo-z diering by less than ±0.05 from that of the cluster), we stacked clusters in various redshift bins to derive colour-magnitude diagrams and galaxy luminosity functions (GLFs). For each galaxy brighter than Mr < - 19.0, we computed the disk and spheroid components by applying SExtractor, and by stacking clusters we determined how the disk-to-spheroid flux ratio varies with cluster redshift and mass. Results. We detected 3663 clusters in the redshift range 0.15 ≤ z ≤ 0.70, with estimated mean masses between ∼1013 and a few 1014 M⊙. We cross-matched our catalogue of candidate clusters with various catalogues extracted from optical and/or X-ray data. The percentages of redetected clusters are at most 40% because in all cases we detect relatively massive clusters, while other authors detect less massive structures. By stacking the cluster galaxies in various redshift bins, we find a clear red sequence in the (ǵ - ŕ) versus ŕ colour-magnitude diagrams, and the GLFs are typical of clusters, though with a possible contamination from field galaxies. The morphological analysis of the cluster galaxies shows that the fraction of late-type to early-type galaxies shows an increase with redshift (particularly in 9σ clusters) and a decrease with detection level, i.e. cluster mass. Conclusions. From the properties of the cluster galaxies, the majority of the candidate clusters detected here seem to be real clusters with typical cluster properties., F.D. acknowledges long-term support from CNES. I.M. acknowledges financial support from the Spanish grants AYA2010-15169 and AYA2013-42227-P and from the Junta de Andalucia through TIC-114 and the Excellence Project P08-TIC-03531. A.T. acknowledges the support and the hospitality of IAP/CNRS for two one month visits. We are grateful to Andrea Biviano for giving us his IDL program to fit GLFs with a Schechter function and to Alberto Cappi for discussions. We thank the six high school students M.A. Garcia Valverde, B. Hernandez Ramos, J. Leon Lovell, L. Martinez Sanchez de Lara, J. Rodriguez Zamorano and L. Vallecillos Azor for their careful eye classification of about 1000 galaxies. Funding for SDSS-III has been provided by the Alfred P. Sloan Foundation, the Participating Institutions, the National Science Foundation, and the US Department of Energy Office of Science. The SDSS-III web site is http://www.sdss3.org/. SDSS-III is managed by the Astrophysical Research Consortium for the Participating Institutions of the SDSS-III Collaboration including the University of Arizona, the Brazilian Participation Group, Brookhaven National Laboratory, Carnegie Mellon University, University of Florida, the French Participation Group, the German Participation Group, Harvard University, the Instituto de Astrofisica de Canarias, the Michigan State/Notre Dame/JINA Participation Group, Johns Hopkins University, Lawrence Berkeley National Laboratory, Max Planck Institute for Astrophysics, Max Planck Institute for Extraterrestrial Physics, New Mexico State University, New York University, Ohio State University, Pennsylvania State University, University of Portsmouth, Princeton University, the Spanish Participation Group, University of Tokyo, University of Utah, Vanderbilt University, University of Virginia, University of Washington, and Yale University.
Published: 2015
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17. HD 172189, a Cluster Member Binary System with a δ Scuti Component in the Field of View of COROT

Author: Juan Carlos Suárez, Ennio Poretti, Andrés Moya, Ignasi Ribas, Pedro J. Amado, Armando Arellano Ferro, Susana Martín-Ruiz, European Southern Observatory (ESO), Instituto de Astrofisica de Andalucia, CSIC (IAA), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Instituto de Astronomia, Universidad Nacional Autonomica de Mexico, Institut dEstudis Espacials de Catalunya/CSIC, and INAF-Osservatorio Astronomico di Brera (INAF-OAB)
Subjects: Physics, Frequency analysis, Field (physics), Astronomy, Binary number, Astronomy and Astrophysics, Astrophysics, Light curve, Spectral line, law.invention, Space and Planetary Science, law, Cluster (physics), Binary system, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Open cluster
Abstract: International audience; Photometric and spectroscopic results for the star HD 172189, member of the open cluster IC 4756 in the summer field of the space mission COROT, are presented. From photometric observations in the Strömgren system carried out at various epochs, its binary nature as well as the presence of a delta Scuti-type pulsating component have been discovered. The frequency analysis of the whole dataset confirms a dominant frequency of 19.5974 c d-1 with a maximum amplitude near 0.02 mag plus other frequencies in the range 18 20 c d-1. A preliminary orbital solution from the light curve and from four FEROS spectra reveals two similar components of around 1.5 M &sun; orbiting with a period of 5.702 d.
Published: 2006
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18. New light on gamma-ray burst host galaxies with Herschel

Author: Silvia Piranomonte, D. Le Borgne, Simone Bianchi, Sylvio Klose, Eliana Palazzi, Jochen Greiner, Elena Pian, Stefano Covino, D. Gotz, Leslie K. Hunt, Sandra Savaglio, E. Le Floc'h, Andrea Rossi, P. Ferrero, S. Berta, Patricia Schady, S. Basa, Michał J. Michałowski, S. D. Vergani, Valerio D'Elia, INAF - Osservatorio Astrofisico di Arcetri, Largo E. Fermi 5, 50125, Firenze, Italy, INAF - IASF Bologna, via Gobetti 101, 40129, Bologna, Italy, Sterrenkundig Observatorium, Universiteit Gent, Max-Planck-Institut fur Extraterrestrische Physik, Giessenbachstrase, 85748, Garching bei Munchen, Germany, Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), INAF-Osservatorio Astronomico di Brera (INAF-OAB), Agenzia Spaziale Italiana (ASI), Instituto de Astrofisica de Andalucia, CSIC (IAA), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Türinger Landessternwarte Tautenburg, Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), INAF-Osservatorio Astronomico di Roma (INAF-OAR), Galaxies, Etoiles, Physique, Instrumentation (GEPI), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astrofisico di Arcetri (OAA), Istituto Nazionale di Astrofisica (INAF), 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), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), and 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)
Subjects: submillimeter: galaxies, Cosmology and Nongalactic Astrophysics (astro-ph.CO), Infrared, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, galaxies: high-redshift, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Galaxy Astrophysics, Physics, COSMIC cancer database, extinction, Spectral density, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Galaxy, Redshift, Wavelength, Orders of magnitude (time), Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), galaxies: star formation, dust, Astrophysics::Earth and Planetary Astrophysics, Gamma-ray burst, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], galaxies: ISM, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract: Until recently, dust emission has been detected in very few host galaxies of gamma-ray bursts (GRBHs). With Herschel, we have now observed 17 GRBHs up to redshift z~3 and detected seven of them at infrared (IR) wavelengths. This relatively high detection rate (41%) may be due to the composition of our sample which at a median redshift of 1.1 is dominated by the hosts of dark GRBs. Although the numbers are small, statistics suggest that dark GRBs are more likely to be detected in the IR than their optically-bright counterparts. Combining our IR data with optical, near-infrared, and radio data from our own datasets and from the literature, we have constructed spectral energy distributions (SEDs) which span up to 6 orders of magnitude in wavelength. By fitting the SEDs, we have obtained stellar masses, dust masses, star-formation rate (SFR), and extinctions for our sample galaxies. We find that GRBHs are galaxies that tend to have a high specfic SFR (sSFR), and like other star-forming galaxies, their ratios of dust-to-stellar mass are well correlated with sSFR. We incorporate our Herschel sample into a larger compilation of GRBHs, and compare this combined sample to SFR-weighted median stellar masses of the widest, deepest galaxy survey to date. This is done in order to establish whether or not GRBs can be used as an unbiased tracer of cosmic comoving SFR density (SFRD) in the universe. In contrast with previous results, this comparison shows that GRBHs are medium-sized galaxies with relatively high sSFRs; stellar masses and sSFRs of GRBHs as a function of redshift are similar to what is expected for star-forming galaxy populations at similar redshifts. We conclude that there is no strong evidence that GRBs are biased tracers of SFRD; thus they should be able to reliably probe the SFRD to early epochs., 18 pages, 9 figures, accepted for publication in A&A. Revised to include Fig. 6, mistakenly omitted in original
Published: 2014
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19. 'TNOs are Cool': A survey of the trans-Neptunian region. XI. A Herschel-PACS view of 16 Centaurs

Author: T. G. Mueller, Cs. Kiss, Esa Vilenius, Nuno Peixinho, E. Lellouch, Noemi Pinilla-Alonso, Michael Mueller, J. L. Ortiz, A. Delsanti, J. A. Stansberry, A. Pal, David Trilling, Pablo Santos-Sanz, S. Fornasier, Rene Duffard, Michael Mommert, Instituto de Astrofisica de Andalucia, CSIC (IAA), Max-Planck-Institut fur extraterrestrische Physik, Postfach 1312, Giessenbachstr., 85741, Garching, Germany, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Deutsches Zentrum für Luft- und Raumfahrt (DLR), Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, Konkoly Thege 15-17, 1121, Budapest, Hungary, SRON Netherlands Institute for Space Research, Space Telescope Science Institute (STScI), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Unidad de Astronomia, Facultad de Ciencias Basicas, Universidad de Antofagasta, and Department of Physics and Astronomy, Northern Arizona University, Flagstaff
Subjects: Earth and Planetary Astrophysics (astro-ph.EP), Mean diameter, Physics, Orbital elements, education.field_of_study, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Population, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Centaur, Photometry (optics), 13. Climate action, Space and Planetary Science, astro-ph.EP, Astrophysics::Earth and Planetary Astrophysics, Monochromatic color, education, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics, Data reduction
Abstract: Centaurs are the transitional population between trans-Neptunian objects (TNOs) and Jupiter-family comets. For this reason it is possible to access the smaller ones, which is more difficult to do with the TNO population. The goal of this work is to characterize a set of 16 Centaurs in terms of their size, albedo, and thermal properties. We study the correlations, for a more extended sample obtained from the literature, of diameter, albedo, orbital parameters, and spectral slopes. We performed three-band photometric observations using Herschel-PACS and used a consistent method for the data reduction and aperture photometry of this sample to obtain monochromatic flux densities at 70, 100, and 160 $��$m. Additionally, we used Spitzer-MIPS flux densities at 24 and 70 $��$m when available. We also included in our Centaur sample scattered disk objects (SDOs), a dynamical family of TNOS, using results previously published by our team, and some Centaurs observed only with the Spitzer/MIPS instrument. We have determined new radiometric sizes and albedos of 16 Centaurs. The first conclusion is that the albedos of Centaur objects are not correlated with their orbital parameters. Similarly, there is no correlation between diameter and orbital parameters. Most of the objects in our sample are dark (pv < 7%) and most of them are small (D < 120km). However, there is no correlation between albedo and diameter, in particular for the group of the small objects as albedo values are homogeneously distributed between 4 to 16%. The correlation with the color of the objects showed that red objects are all small (mean diameter 65 km), while the gray ones span a wide range of sizes (mean diameter 120 km). Moreover, the gray objects tend to be darker, with a mean albedo of 5.6%, compared with a mean of 8.5% (ranging from 5 to 15%) for the red objects., 16 pages, 7 figures. accepted at A&A. in press
Published: 2014
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20. Integral-field spectroscopy of (90482) Orcus-Vanth

Author: Audrey Thirouin, Benoit Carry, Francesca E. DeMeo, David Farrelly, Thomas G. Müller, J. Berthier, Daniel Hestroffer, Pedro Lacerda, A. Doressoundiram, Bruno Sicardy, Christophe Dumas, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Agence Spatiale Européenne = European Space Agency (ESA), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Department of Earth, Atmospheric and Planetary Sciences [MIT, Cambridge] (EAPS), Massachusetts Institute of Technology (MIT), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Astrophysics Research Centre [Belfast] (ARC), Queen's University [Belfast] (QUB), Institut Universitaire de France (IUF), Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.), European Southern Observatory (ESO), Chemistry and biochemistry department, Utah State University (USU), Max-Planck-Institut für Extraterrestrische Physik (MPE), European Space Astronomy Centre (ESAC), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Université Paris Cité (UPCité), Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Instituto de Astrofisica de Andalucia, CSIC (IAA), Queen's University, Sorbonne Université (SU), European Southern Observatory, Utah State University, Max-Planck-Institut für Extraterrestriche Physik (MPE), Agence Spatiale Européenne (ESA), European Space Agency (ESA), Centre National de la Recherche Scientifique (CNRS)-Université de Lille-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)
Subjects: 010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Phase (waves), [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Astrophysics, 01 natural sciences, Spectral line, Techniques: high angular resolution, Methods: observational, Techniques:imaging spectroscopy, Observatory, 0103 physical sciences, Field spectroscopy, 010303 astronomy & astrophysics, Spectrograph, 0105 earth and related environmental sciences, Orbital elements, Physics, Earth and Planetary Astrophysics (astro-ph.EP), Kuiper belt objects: individual: (90482) Orcus, Very Large Telescope, Astronomy and Astrophysics, 13. Climate action, Space and Planetary Science, Absorption band, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics
Abstract: Aims. We seek to constrain the surface composition of the Trans-Neptunian Object (90482) Orcus and its small satellite Vanth, as well as their mass and density. Methods. We acquired near-infrared spectra (1.4-2.4 {\mu}m) of (90482) Orcus and its companion Vanth using the adaptive-optics-fed integral-field spectrograph SINFONI mounted on Yepun/UT4 at the European Southern Observatory Very Large Telescope. We took advantage of a very favorable appulse (separation of only 4") between Orcus and the UCAC2 29643541 star (R = 11.6) to use the adaptive optics mode of SINFONI, allowing both components to be spatially resolved and Vanth colors to be extracted independently from Orcus. Results. The spectrum of Orcus we obtain has the highest signal-to-noise ratio to date, and we confirm the presence of H2O ice in crystalline form, together with the presence of an absorption band at 2.2 {\mu}m. We set an upper limit of about 2% for the presence of methane, and 5% for ethane. Because the methane alone cannot account for the 2.2 {\mu}m band, the presence of ammonia is suggested to the level of a couple of percent. The colors of Vanth are found slightly redder than those of Orcus, but the large measurement uncertainties forbid us from drawing conclusions on the origin of the pair (capture or co-formation). Finally, we reset the orbital phase of Vanth around Orcus, and confirm the orbital parameters derived by Brown et al. (2010, AJ 139)., Comment: 9 pages, 6 figures, 6 tables, accepted for publication in A&A
Published: 2011
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21. Monitoring a high-amplitude delta Scuti star for 152 days: discovery of 12 additional modes and modulation effects in the light curve of CoRoT 101155310

Author: Margit Paparo, Werner W. Weiss, Jonas Debosscher, L. Mantegazza, J. M. Benko, Zsofia Bognar, Michel Auvergne, A. Moya, Rafa Garrido, Frédéric Baudin, Ennio Poretti, Ewa Niemczura, Juan Carlos Suárez, Monica Rainer, Annie Baglin, INAF-Osservatorio Astronomico di Brera (INAF-OAB), Institut für Astronomie, Universität Wien (IfA), Konkoly Observatory, Research Center for Astronomy and Earth Sciences, Centro de Astrobiología LAEX (CSIC-INTA), Instituto de Astrofisica de Andalucia, CSIC (IAA), Astronomical Institute, University of Wroclaw, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Etoile, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Institut d'astrophysique spatiale (IAS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), and Instituut voor Sterrenkunde, Katholieke Universiteit Leuven
Subjects: oscillations [stars], Blazhko effect, rr-lyrae stars, FOS: Physical sciences, Astrophysics, oscillation code, rotation, Spectral line, variable-stars, Modulation (music), bolometric corrections, variables: delta scuti [stars], 2mass, Solar and Stellar Astrophysics (astro-ph.SR), Physics, interiors [stars], Oscillation, petersen diagrams, excitation, Astronomy and Astrophysics, Light curve, Stars, Amplitude, pulsating stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Noise (radio), individual: corot 101155310 [stars]
Abstract: The detection of small-amplitude nonradial modes in high-amplitude Delta Sct (HADS) variables has been very elusive until at least five of them were detected in the light curve of V974 Oph obtained from ground-based observations. The combination of radial and nonradial modes has a high asteroseismic potential, thanks to the strong constraints we can put in the modelling. The continuous monitoring of ASAS 192647-0030.0=CoRoT 101155310 (P=0.1258 d, V=13.4) ensured from space by the CoRoT (Convection, Rotation and planetary Transits) mission constitutes a unique opportunity to exploit such potential. The 22270 CoRoT measurements were performed in the chromatic mode. They span 152 d and cover 1208 consecutive cycles. After the correction for one jump and the long-term drift, the level of the noise turned out to be 29 micromag. The phase shifts and amplitude ratios of the coloured CoRoT data, the HARPS spectra, and the period-luminosity relation were used to determine a self-consistent physical model. In turn, it allowed us to model the oscillation spectrum, also giving feedback on the internal structure of the star. In addition to the fundamental radial mode f1=7.949 c/d with harmonics up to 10f1, we detected 12 independent terms. Linear combinations were also found and the light curve was solved by means of 61 frequencies (smallest amplitude 0.10 mmag). The newest result is the detection of a periodic modulation of the f1 mode (triplets at +/-0.193 c/d centred on f1 and 2f1), discussed as a rotational effect or as an extension of the Blazhko effect to HADS stars. The physical model suggests that CoRoT 101155310 is an evolved star, with a slight subsolar metallic abundance, close to the terminal age main sequence. All the 12 additional terms are identified with mixed modes in the predicted overstable region., 10 pages, 6 figures, Tables 1 and 2 available at CDS after publication. Accepted for publication in Astronomy and Astrophysics
Published: 2011
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22. First detection of hydrogen isocyanide (HNC) in Titan's atmosphere

Author: Paul Hartogh, L. M. Lara, Miriam Rengel, R. Moreno, Dominique Bockelée-Morvan, Emmanuel Lellouch, Régis Courtin, A. Gonzalez, Marek Banaszkiewicz, N. Biver, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Instituto de Astrofisica de Andalucia, CSIC (IAA), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, and Space Research Centre, Polish Academy of Sciences (Wroclaw)
Subjects: Physics, Hydrogen isocyanide, Rotational transition, Astronomy and Astrophysics, symbols.namesake, chemistry.chemical_compound, chemistry, Space and Planetary Science, symbols, Radiative transfer, Emission spectrum, Atomic physics, Thermosphere, Ionosphere, Titan (rocket family), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Dissociative recombination
Abstract: International audience; We report on the first identification of hydrogen isocyanide (HNC) in Titan's atmosphere, from observations using the HIFI instrument on the Herschel Space Observatory. An emission line from the HNC J = 6 --> 5 rotational transition at 543.897 GHz was measured in Titan on June 14 and December 31, 2010. Radiative transfer modeling indicates that the bulk of HNC is located above 400 km, with a column density in the range (0.6-1.5) × 1013 cm-2, but the observations cannot establish its vertical profile. In particular HNC could be restricted to the upper thermosphere (~1000 km), in which case its local abundance relative to HCN could be as high as ~0.3. HNC is probably formed mostly at ionospheric levels (950-1150 km) from dissociative recombination of HCNH+ and possibly other heavier nitrile ions. Ionospheric loss of HNC occurs by protonation with XH+ ions. Additional formation (e.g. from N(4S) +3CH2) and loss routes (e.g. from isomerization to HCN) in the neutral atmosphere remain to be investigated.
Published: 2011
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23. On the interpretation of echelle diagrams for solar-like oscillations. Effect of centrifugal distortion

Author: François Lignières, Daniel R. Reese, Michel Rieutord, Marie-Jo Goupil, Juan Carlos Suárez, Reza Samadi, J. Lochard, Instituto de Astrofisica de Andalucia, CSIC (IAA), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Astronomie du LESIA, 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)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Ingénieurs, Techniciens et Administratifs, Laboratoire Astrophysique de Toulouse-Tarbes (LATT), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, Oscillation, Stellar rotation, FOS: Physical sciences, Astronomy and Astrophysics, Context (language use), Rotation, Spectral line, Computational physics, Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics::Solar and Stellar Astrophysics, Solar-like oscillations, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Stellar evolution, Solar and Stellar Astrophysics (astro-ph.SR)
Abstract: This work aims at determining the impact of slow to moderate rotation on the regular patterns often present in solar-like oscillation spectra. We focus on the well-known asteroseismic diagnostic echelle diagrams, examining how rotation may modify the estimates of the large and small spacings, as well as the identification of modes. We illustrate the work with a real case: the solar-like star $\eta$ Bootis. The modeling takes into account rotation effects on the equilibrium models through an effective gravity and on the oscillation frequencies through both perturbative and non-perturbative calculations. We compare the results of both type of calculations in the context of the regular spacings (like the small spacings and the scaled small spacings) and echelle diagrams. We show that for echelle diagrams the perturbative approach remains valid for rotational velocities up to 40-50 km/s. We show that for the rotational velocities measured in solar-like stars, theoretical oscillation frequencies must be corrected up to the second-order in terms of rotation rate, including near degeneracy effects. For rotational velocities of about 16 km/S and higher, diagnostics on large spacings and on modal identification through echelle diagrams can be significantly altered by the presence of the $m\neq0$ components of the rotationally split modes. We found these effects to be detectable in the observed frequency range. Analysis of the effects of rotation on small spacings and scaled small spacings reveals that these can be of the order of, or even larger than surface effects, typically turbulence, microscopic diffusion, etc. Furthermore, we show that scaled spacings are significantly affected by stellar distortion even for small stellar rotational velocities (from 10-15 km/s) and therefore some care must be taken when using them as indicators for probing deep stellar interiors., Comment: 10 pages,5 figures, accepted for publication in ApJ; http://iopscience.iop.org/0004-637X/721/1/537/
Published: 2010
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24. Water production in comet 81P/Wild 2 as determined by Herschel/HIFI

Author: Nicolas Biver, Emmanuel Jehin, A. Di Giorgio, Miriam Rengel, M. I. Błęcka, José Cernicharo, Geoffrey A. Blake, S. Philipp, M. de Val-Borro, Christoffel Waelkens, Joris Blommaert, Slawomira Szutowicz, R. Szczerba, Alexander S. Medvedev, Michael Küppers, Pierre Encrenaz, Dariusz C. Lis, Paul Hartogh, Paolo Saraceno, T. Encrenaz, David A. Naylor, Bart Vandenbussche, Dominique Bockelée-Morvan, Raphael Moreno, Luisa Lara, Volker Ossenkopf, P. Zaal, Emmanuel Lellouch, R. Shipman, Martin Emprechtinger, Leen Decin, B. M. Swinyard, T. de Graauw, F. Bensch, Jacques Crovisier, C. Jarchow, R. Schieder, Jean Manfroid, N. Thomas, Marek Banaszkiewicz, T. Klein, M. Kidger, Edwin Bergin, Daphne Stam, Damien Hutsemekers, Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Space Research Centre, Polish Academy of Sciences (Wroclaw), German Aerospace Centre (DLR), Institut d'Astrophysique, Géophysique et Océanographie, Université de Liège, Rosetta Science Operations Centre, Instituto de Astrofisica de Andalucia, CSIC (IAA), STFC Rutherford Appleton Laboratory, Harwell Innovation Campus, Didcot, Instituut voor Sterrenkunde, Katholieke Universiteit Leuven, Astronomy Department, University of Michigan, Laboratorio de Astrofísica Molecular, CAB-CSIC/INTA (LAM), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Instrumentation et télédétection, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Dynamique des milieux interstellaires et plasmas stellaires, Joint ALMA Observatory, Santiago, Science Centre, Department of Physics and Astronomy, University of Lethbridge, Physikalisches Institut, Universität zu Köln, SRON Netherlands Institute for Space Research, Physikalisches Institut, Universität Bern, Centrum Astronomiczne im. M. Kopernika, Torun (CAMK), Istituto Fisica Spazio Interplanetario, INAF, Max-Planck-Institut für Radioastronomie (MPIfR), and Astronomy
Subjects: Electron density, 010504 meteorology & atmospheric sciences, Mean kinetic temperature, SURFACE, Infrared, Comet, FOS: Physical sciences, Astrophysics, Electron, 01 natural sciences, SPACECRAFT, 0103 physical sciences, H2O, Spectral resolution, 010303 astronomy & astrophysics, SATELLITE, 0105 earth and related environmental sciences, Line (formation), Physics, Earth and Planetary Astrophysics (astro-ph.EP), ASTRONOMY, Astronomy and Astrophysics, submillimeter: general, molecular processes, 13. Climate action, Space and Planetary Science, radiative transfer, ODIN, comets: individual: 81P/Wild 2, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Excitation, HIFI, Astrophysics - Earth and Planetary Astrophysics
Abstract: The high spectral resolution and sensitivity of Herschel/HIFI allows for the detection of multiple rotational water lines and accurate determinations of water production rates in comets. In this letter we present HIFI observations of the fundamental 110-101 (557 GHz) ortho and 111-000 (1113 GHz) para rotational transitions of water in comet 81P/Wild 2 acquired in February 2010. We mapped the extent of the water line emission with five point scans. Line profiles are computed using excitation models which include excitation by collisions with electrons and neutrals and solar infrared radiation. We derive a mean water production rate of $1.0 \times 10^{28}$ molecules s$^{-1}$ at a heliocentric distance of 1.61 AU about 20 days before perihelion, in agreement with production rates measured from the ground using observations of the 18-cm OH lines. Furthermore, we constrain the electron density profile and gas kinetic temperature, and estimate the coma expansion velocity by fitting the water line shapes., Accepted for publication in A&A (special issue on HIFI first results)
Published: 2010
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25. A study of the distant activity of comet C/2006 W3 (Christensen) using Herschel and ground-based radio telescopes

Author: L. M. Lara, Trevor Fulton, Miriam Rengel, M. R. Kidger, G. A. Blake, R. Moreno, Emmanuel Jehin, E. Lellouch, Michael Küppers, David A. Naylor, C. Waelkens, D. C. Lis, T. de Graauw, E. A. Bergin, Jean Manfroid, M. I. Blecka, T. Encrenaz, M. de Val-Borro, L. Decin, J. Crovisier, Slawomira Szutowicz, Christopher Jarchow, Bart Vandenbussche, José Cernicharo, J. A. D. L. Blommaert, Damien Hutsemekers, N. Thomas, Paul Hartogh, Dominique Bockelée-Morvan, Alexander S. Medvedev, Sarah Leeks, Marek Banaszkiewicz, Rudolf Schieder, P. J. Encrenaz, F. Bensch, B. M. Swinyard, N. Biver, Martin Emprechtinger, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Instituut voor Sterrenkunde, Katholieke Universiteit Leuven, Rutherford Appleton Laboratory, Cahill Center for Astronomy and Astrophysics, California Institute of Technology, Institut d'Astrophysique, Géophysique et Océanographie, Université de Liège, European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA), Instituto de Astrofisica de Andalucia, CSIC (IAA), Space Research Centre, Polish Academy of Sciences (Wroclaw), Deutsches Zentrum für Luft- und Raumfahrt (DLR), Blue Sky Spectroscopy (BSS), Herschel Science Center, ESAC/ESA, Astronomy Department, University of Michigan, Centro de Astrobiología, Consejo Superior de Investigaciones Científicas (CSIC)/Instituto Nacional de Técnica Aeroespacial (INTA) (CAB), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Instrumentation et télédétection, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Dynamique des milieux interstellaires et plasmas stellaires, SRON Netherlands Institute for Space Research, Department of Physics, University of Lethbridge, Lulea University of Technology (LTU), and University of Bern (UBERN)
Subjects: Earth and Planetary Astrophysics (astro-ph.EP), Physics, Range (particle radiation), Continuum (design consultancy), Comet, FOS: Physical sciences, Astronomy and Astrophysics, Coma (optics), Astrophysics, Spectral line, Radio telescope, Spire, Space and Planetary Science, Spectral energy distribution, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics
Abstract: Comet C/2006 W3 (Christensen) was observed in November 2009 at 3.3 AU from the Sun with Herschel. The PACS instrument acquired images of the dust coma in 70- and 160-micrometers filters, and spectra covering several H2O rotational lines. Spectra in the range 450-1550 GHz were acquired with SPIRE. The comet emission continuum from 70 to 672 micrometers was measured, but no lines were detected. The spectral energy distribution indicates thermal emission from large particles and provides a measure of the size distribution index and dust production rate. The upper limit to the water production rate is compared to the production rates of other species (CO, CH3OH, HCN, H2S, OH) measured with the IRAM 30-m and Nancay telescopes. The coma is found to be strongly enriched in species more volatile than water, in comparison to comets observed closer to the Sun. The CO to H2O production rate ratio exceeds 220%. The dust to gas production rate ratio is on the order of 1., Accepted for publication in Astronomy & Astrophysics (special issue on Herschel first results)
Published: 2010
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26. Photometric variability of the Be star CoRoT-ID 102761769

Author: Anne-Marie Hubert, Coralie Neiner, B. de Batz, Annie Baglin, T. Semaan, Juan Gutiérrez-Soto, M. Floquet, Yves Fremat, Marcelo Emilio, P. D. Diago, J. Suso, Christophe Martayan, B. Leroy, A. L. Huat, Eduardo Janot-Pacheco, L. Andrade, Juan Fabregat, F. Espinosa Lara, Juan Carlos Suárez, Obervatório Astronômico, Universidade Estadual de Ponta Grossa, Instituto Astronômico e Geofísico, Universidade de São Paulo (IAG), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Universitat de València (UV), Instituto de Astrofisica de Andalucia, CSIC (IAA), Galaxies, Etoiles, Physique, Instrumentation (GEPI), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Physique stellaire et galactique, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-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 Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Observatoire Royal de Belgique (ORB), and European Organization for Astronomical Research in the Southern Hemisphere
Subjects: 010504 meteorology & atmospheric sciences, Be star, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Type (model theory), 01 natural sciences, Partícules (Física nuclear), Luminosity, symbols.namesake, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, Stellar rotation, Balmer series, Astronomy and Astrophysics, Circumstellar envelope, Light curve, Stars, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Esteroides, symbols, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: Classical Be stars are rapid rotators of spectral type late O to early A and luminosity class V-III, wich exhibit Balmer emission lines and often a near infrared excess originating in an equatorially concentrated circumstellar envelope, both produced by sporadic mass ejection episodes. The causes of the abnormal mass loss (the so-called Be phenomenon) are as yet unknown. For the first time, we can now study in detail Be stars outside the Earth's atmosphere with sufficient temporal resolution. We investigate the variability of the Be Star CoRoT-ID 102761769 observed with the CoRoT satellite in the exoplanet field during the initial run. One low-resolution spectrum of the star was obtained with the INT telescope at the Observatorio del Roque de los Muchachos. A time series analysis was performed using both cleanest and singular spectrum analysis algorithms to the CoRoT light curve. To identify the pulsation modes of the observed frequencies, we computed a set of models representative of CoRoT-ID 102761769 by varying its main physical parameters inside the uncertainties discussed. We found two close frequencies related to the star. They are 2.465 $\rm c\,d^{-1}$ (28.5 $\mathrm{\mu Hz}$) and 2.441 $\rm c\,d^{-1}$ (28.2 $\mathrm{\mu Hz}$). The precision to which those frequencies were found is 0.018 $\rm c\,d^{-1}$ (0.2 $\mathrm{\mu Hz}$). The projected stellar rotation was estimated to be 120 $\rm km\,s^{-1}$ from the Fourier transform of spectral lines. If CoRoT-ID 102761769 is a typical Galactic Be star it rotates near the critical velocity. The critical rotation frequency of a typical B5-6 star is about 3.5 $\rm c\,d^{-1}$(40.5 $\mathrm{\mu Hz}$), which implies that the above frequencies are really caused by stellar pulsations rather than star's rotation., Comment: 9 pages, 8 figures, accepted: 13 June 2010 Astronomy & Astrophysics
Published: 2010
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27. Modelling results for two late Be stars observed by CoRoT

Author: Juan Gutiérrez-Soto, Hideyuki Saio, C. Lovekin, Coralie Neiner, S. Mathis, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Galaxies, Etoiles, Physique, Instrumentation (GEPI), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Astronomical Institute, Tohoku University, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), and Instituto de Astrofisica de Andalucia, CSIC (IAA)
Subjects: Physics, Photosphere, K-type main-sequence star, Astronomy, Astronomy and Astrophysics, Astrophysics, Rotation, Stars, Amplitude, Space and Planetary Science, Stellar mass loss, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Adiabatic process, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Stellar evolution
Abstract: The Be stars HD 181231 (B5IVe) and HD 175869 (B8IIIe) have recently been observed using the CoRoT satellite for ∼5 months and ∼27 days respectively. This continuous, space-based observation has allowed for the detection of many low amplitude modes in these stars. In the case of HD181231, the combination of the CoRoT data and ground-based spectroscopic follow-up data have placed tight constraints on the fundamental and pulsational properties of the star, allowing for detailed seismic modelling. For HD 175869, the variability has been proposed to be the result of inhomogeneities produced by stellar activity, located in or just above the photosphere. However, the CoRoT data does not exclude non-radial pulsations as the origin of the variability. Through seismic modelling, we hope to clarify the origins of the variability. We compare observed frequencies to those calculated using a 2D stellar evolution and a 2D linear adiabatic pulsation code. We match the observed frequencies to a grid of 2D models in order to constrain the mass, age, rotation velocity and amount of convective core overshoot. We also compare our results to frequencies calculated using a 1D non-adiabatic pulsation code. Using a combination of frequencies, we have been able to constrain the rotation and extra mixing for stars of a known mass and age. Here we determine the best fitting mass, age, rotation velocity and amount of extra mixing for these Be stars (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Published: 2010
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28. Ground-based follow-up in relation to Kepler Asteroseismic Investigation

Author: K. Uytterhoeven, M. Briquet, H. Bruntt, P. De Cat, S. Frandsen, J. Gutiérrez-Soto, L. Kiss, D.W. Kurtz, M. Marconi, J. Molenda-Żakowicz, R. Østensen, S. Randall, J. Southworth, R. Szabó, null KASC Working Groups on ground-based, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Instituut voor Sterrenkunde, Katholieke Universiteit Leuven, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Observatoire Royal de Belgique (ORB), Danish AsteroSeismology Centre (DASC), Instituto de Astrofisica de Andalucia, CSIC (IAA), Konkoly Observatory, Research Center for Astronomy and Earth Sciences, Jeremiah Horrocks Institute of Astrophysics, University of Central Lancashire, INAF-Osservatorio Astronomico di Capodimonte (INAF-OAC), Instytut Astronomiczny, Uniwersytet Wroclawski, European Southern Observatory (ESO), and University of Warwick [Coventry]
Subjects: Physics, Metallicity, Newtonian telescope, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Nordic Optical Telescope, law.invention, Telescope, Stars, Photometry (astronomy), Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Observatory, law, William Herschel Telescope, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Solar and Stellar Astrophysics (astro-ph.SR)
Abstract: The Kepler space mission, successfully launched in March 2009, is providing continuous, high-precision photometry of thousands of stars simultaneously. The uninterrupted time-series of stars of all known pulsation types are a precious source for asteroseismic studies. The Kepler data do not provide information on the physical parameters, such as effective temperature, surface gravity, metallicity, and vsini, which are crucial for successful asteroseismic modelling. Additional ground-based time-series data are needed to characterize mode parameters in several types of pulsating stars. Therefore, ground-based multi-colour photometry and mid/high-resolution spectroscopy are needed to complement the space data. We present ground-based activities within KASC on selected asteroseismic Kepler targets of several pulsation types. (Based on observations made with the Isaac Newton Telescope, William Herschel Telescope, Nordic Optical Telescope, Telescopio Nazionale Galileo, Mercator Telescope (La Palma, Spain), and IAC-80 (Tenerife, Spain). Also based on observations taken at the observatories of Sierra Nevada, San Pedro Martir, Vienna, Xinglong, Apache Point, Lulin, Tautenburg, Loiano, Serra la Nave, Asiago, McDonald, Skinakas, Pic du Midi, Mauna Kea, Steward Observatory, Mt Wilson, Bialkow Observatory of the Wroclaw University, Piszkesteto Mountain Station, Observatoire de Haute Provence, and Centro Astronomico Hispano Aleman at Calar Alto. Based on data from the AAVSO International Database.), Comment: 4 pages, 1 figure, Astronomische Nachrichten, HELASIV conference, Lanzarote, February 2010, submitted
Published: 2010
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29. 'TNOs are Cool': A survey of the trans-Neptunian region. I. Results from the Herschel science demonstration phase (SDP)

Author: B. M. Swinyard, Miriam Rengel, L. M. Lara, T. G. Mueller, Paul Hartogh, S. Fornasier, R. Moreno, Nicolas Thomas, Esa Vilenius, Olivier Hainaut, Daniel Hestroffer, Jonathan Horner, Pablo Santos-Sanz, E. Dotto, John Stansberry, David Trilling, A. Delsanti, M. R. Kidger, P. J. Gutierrez, Tanya Lim, Rene Duffard, Alain Doressoundiram, J. Crovisier, Michael Mueller, Florence Henry, Michael Mommert, Pedro Lacerda, Cs. Kiss, Olivier Groussin, Audrey Thirouin, Alan W. Harris, Silvia Protopapa, Antonella Barucci, J. L. Ortiz, E. Lellouch, Max-Planck-Institut für Extraterrestriche Physik (MPE), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), University of Arizona (UoA), Konkoly Observatory, Research Center for Astronomy and Earth Sciences, Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Observatoire de la Côte d'Azur (OCA), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Instituto de Astrofisica de Andalucia, CSIC (IAA), Deutsches Zentrum für Luft- und Raumfahrt (DLR), Department of Physics and Astronomy, Durham University, Queen's University [Belfast] (QUB), Space Science and Technology Department, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, Oxon UK, Department of Physics and Astronomy, Northern Arizona University, Flagstaff, INAF-Osservatorio Astronomico di Roma (INAF-OAR), European Southern Observatory (ESO), Institut de Mécanique Céleste et de Calcul des Ephémérides (IMCCE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Groupe Astrométrie et Planétologie (GAP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Herschel Science Center, ESAC/ESA, University of Bern (UBERN), Laboratoire de Cosmologie, Astrophysique Stellaire & Solaire, de Planétologie et de Mécanique des Fluides (CASSIOPEE), Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), DLR Institute of Planetary Research, German Aerospace Center (DLR), Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG), Centre National de la Recherche Scientifique (CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Institut national des sciences de l'Univers (INSU - CNRS), Laboratoire de Probabilités et Modèles Aléatoires (LPMA), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université Pierre et Marie Curie - Paris 6 (UPMC), Max-Planck-Institut für Sonnensystemforschung (MPS), INAF - Osservatorio Astronomico di Roma (OAR), Istituto Nazionale di Astrofisica (INAF), Centre National de la Recherche Scientifique (CNRS)-Université de Lille-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Nord]), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Solar System, 010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Astrophysics, Color temperature, 01 natural sciences, 0103 physical sciences, Thermal, Range (statistics), Kuiper belt: general / methods: observational / techniques: photometric / instrumentation: photometers / infrared: planetary systems, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, Earth and Planetary Astrophysics (astro-ph.EP), Debris disk, Mode (statistics), Astronomy and Astrophysics, Centaur, Albedo, Astrophysics - Astrophysics of Galaxies, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics
Abstract: The goal of the Herschel Open Time Key programme "TNOs are Cool!" is to derive the physical and thermal properties for a large sample of Centaurs and trans-Neptunian objects (TNOs), including resonant, classical, detached and scattered disk objects. We present results for seven targets either observed in PACS point-source, or in mini scan-map mode. Spitzer-MIPS observations were included for three objects. The sizes of these targets range from 100 km to almost 1000 km, five have low geometric albedos below 10%, (145480) 2005 TB190 has a higher albedo above 15%. Classical thermal models driven by an intermediate beaming factor of $\eta$=1.2 or $\eta$-values adjusted to the observed colour temperature fit the multi-band observations well in most cases. More sophisticated thermophysical models give very similar diameter and albedo values for thermal inertias in the range 0-25 Jm-2s-0.5K-1, consistent with very low heat conductivities at temperatures far away from the Sun. The early experience with observing and model strategies will allow us to derive physical and thermal properties for our complete Herschel TNO sample of 140 targets as a benchmark for understanding the solar system debris disk, and extra-solar ones as well., Comment: 5 pages, 2 figures, accepted for publication in the A&A Herschel Special Issue
Published: 2010
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30. Observation of light echoes around very young stars

Author: Jose Luis Ortiz, Nicolás Morales, Mario Daniel Melita, Ricardo Gil-Hutton, Pablo Santos-Sanz, Rene Duffard, Ben Sugerman, I. de la Cueva, Instituto de Astrofisica de Andalucia, CSIC (IAA), Department of Physics and Astronomy, Goucher College, Astroimagen, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Complejo Astronómico El Leoncito (CASLEO), and Instituto de Astronomía y Física del Espacio, Universidade de Buenos Aires (IAFE)
Subjects: Physics, Solar System, Brightness, Be star, Young stellar object, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Radius, T Tauri star, Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Variable star, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Solar and Stellar Astrophysics (astro-ph.SR)
Abstract: The goal of the paper is to present new results on light echoes from young stellar objects. Broad band CCD images were obtained over three months at one-to-two week intervals for the field of NGC 6726, using the large field-of-view remotely-operated telescope on top of Cerro Burek. We detected scattered light echoes around two young, low-amplitude, irregular variable stars. Observations revealed not just one, but multiple light echoes from brightness pulses of the T Tauri star S CrA and the Herbig Ae/Be star R CrA. Analysis of S CrA's recurring echoes suggests that the star is located 138 +/- 16 pc from Earth, making these the closest echoes ever detected. The environment that scatters the stellar light from S CrA is compatible with an incomplete dust shell or an inclined torus some 10,000 AU in radius and containing $\sim$ $2 \times 10^{-3}$ $M_{\sun}$ of dust. The cause of such concentration at $\sim$ 10,000AU from the star is unknown. It could be the remnant of the envelope from which the star formed, but the distance of the cloud is remarkably similar to the nominal distance of the Oort cloud to the Sun, leading us to also speculate that the dust (or ice) seen around S CrA might have the same origin as the Solar System Oort cloud., Comment: A&A, in press Received: 16 March 2010 / Accepted: 01 June 2010
Published: 2010
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31. CoRoT photometry and high-resolution spectroscopy of the interacting eclipsing binary AU Monocerotis

Author: P. Mathias, M. Rainer, C. Neiner, M. Desmet, Carla Maceroni, Maryline Briquet, F. Baudin, Conny Aerts, E. Poretti, Patricia Lampens, Yves Fremat, Petr Harmanec, J. C. Valtier, E. Janot Pacheco, P. Degroote, K. Uytterhoeven, Andrej Prsa, Pedro J. Amado, Instituut voor Sterrenkunde, Katholieke Universiteit Leuven, Observatoire Royal de Belgique (ORB), Institut d'astrophysique spatiale (IAS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Astronomical Institute, Charles University, Departamento de Astronomia Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Universidade de São Paulo, Observatoire de Paris, Université Paris sciences et lettres (PSL), Laboratoire Hippolyte Fizeau (FIZEAU), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), INAF-Osservatorio Astronomico di Brera (INAF-OAB), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Instituto de Astrofisica de Andalucia, CSIC (IAA), Department of Astronomy and Astrophysics, Villanova University, and INAF-Osservatorio Astronomico di Roma (INAF-OAR)
Subjects: Physics, Brightness, 010308 nuclear & particles physics, Astronomy, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Mass ratio, Light curve, 01 natural sciences, Photometry (optics), Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, 0103 physical sciences, Orbital motion, ComputingMethodologies_DOCUMENTANDTEXTPROCESSING, Roche lobe, Circumbinary planet, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Spectroscopy, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR)
Abstract: Analyses of very accurate CoRoT space photometry, past Johnson V photoelectric photometry and high-resolution \'echelle spectra led to the determination of improved and consistent fundamental stellar properties of both components of AU Mon. We derived new, accurate ephemerides for both the orbital motion (with a period of 11.113d) and the long-term, overall brightness variation (with a period of 416.9d) of this strongly interacting Be + G semi-detached binary. It is shown that this long-term variation must be due to attenuation of the total light by some variable circumbinary material. We derived the binary mass ratio $M_{\rm G}/M_{\rm B}$ = 0.17\p0.03 based on the assumption that the G-type secondary fills its Roche lobe and rotates synchronously. Using this value of the mass ratio as well as the radial velocities of the G-star, we obtained a consistent light curve model and improved estimates of the stellar masses, radii, luminosities and effective temperatures. We demonstrate that the observed lines of the B-type primary may not be of photospheric origin. We also discover rapid and periodic light changes visible in the high-quality residual CoRoT light curves. AU Mon is put into perspective by a comparison with known binaries exhibiting long-term cyclic light changes., Comment: Accepted for publication in MNRAS
Published: 2010
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32. A PRECISE ASTEROSEISMIC AGE AND RADIUS FOR THE EVOLVED SUN-LIKE STAR KIC 11026764

Author: V. Silva Aguirre, Graham A. Verner, David G. Koch, J. Molenda-Zakowicz, O. L. Creevey, P. Eggenberger, William J. Chaplin, Daniel Huber, Savita Mathur, S. Frandsen, A.-M. Broomhall, T. S. Metcalfe, Tiago L. Campante, Stephen T. Fletcher, Michael Thompson, Antonio Frasca, Roger New, Alfio Bonanno, P.-O. Quirion, Rasmus Handberg, M. Di Mauro, I. N. Kitiashvili, D. Salabert, Jesper Schou, Timothy M. Brown, Timothy R. White, K. H. Sato, Timothy R. Bedding, S. Dreizler, Rafael A. García, Jørgen Christensen-Dalsgaard, Saskia Hekker, Juan Carlos Suárez, L. Esch, A. Moya, Hans Kjeldsen, Paul Wilson, J. P. Marques, Thierry Appourchaux, Clara Régulo, Yvonne Elsworth, Dennis Stello, G. Doğan, J. Ballot, Sarbani Basu, William J. Borucki, Jon M. Jenkins, R. L. Gilliland, Christoffer Karoff, Katia Biazzo, Alexander G. Kosovichev, S. G. Sousa, Ian W. Roxburgh, Ning Gai, M. Bazot, L. Piau, Mário J. P. F. G. Monteiro, H. Bruntt, Faculdade de Ciências, High Altitude Observatory, National Center for Atmospheric Research, Centro de Astrofísica, Universidade do Porto, University of Sheffield [Sheffield], Astronomical Institute, University of Wroclaw, Institut d'astrophysique spatiale (IAS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), School of Physics and Astronomy, University of Birmingham, Danish AsteroSeismology Centre (DASC), Observatoire Astronomique de l'Université de Genève, Sydney Institute for Astronomy (SIfA), Observatoire de Paris, Université Paris sciences et lettres (PSL), Instituto de Astrofísica de Canarias (IAC), Canadian Space Agency (CSA), INAF-Osservatorio Astrofisico di Catania (INAF-OACt), Max-Planck-Institut für Astrophysik (MPA), Department of Astronomy, Yale University, Istituto di Astrofisica Spaziale e Fisica Cosmica (IASF-Roma), HEPL, Stanford University, Stanford, Center for Turbulence Research, Stanford University, Instituto de Astrofisica de Andalucia, CSIC (IAA), Laboratorio de Astrofísica, CAB (CSIC-INTA), Villanueva de la Cañada, Madrid, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), INAF-Osservatorio Astrofisico di Arcetri (INAF-OAA), Institut für Astrophysik, Universität Göttingen, Nordic Optical Telescope, Las Cumbres Observatory, Goleta, Space Telescope Science Institute (STScI), Materials Engineering Research Institute, Sheffield Hallam University, Sheffield, Astronomy Unit, Queen Mary, Laboratoire Astrophysique de Toulouse-Tarbes (LATT), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), National Aeronautics and Space Administration, Ames Research Center, and SETI Institute, NASA Ames Research Center, Moffett Field
Subjects: Astronomia, Física, Física [Ciências exactas e naturais], FOS: Physical sciences, Astrophysics, Star (graph theory), 01 natural sciences, Physical sciences [Natural sciences], Planet, Astronomy, Physical sciences, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, Physics, Earth and Planetary Astrophysics (astro-ph.EP), 010308 nuclear & particles physics, Oscillation, Subgiant, Astronomy and Astrophysics, Radius, Exoplanet, Stars, Photometry (astronomy), Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics
Abstract: The primary science goal of the Kepler Mission is to provide a census of exoplanets in the solar neighborhood, including the identification and characterization of habitable Earth-like planets. The asteroseismic capabilities of the mission are being used to determine precise radii and ages for the target stars from their solar-like oscillations. Chaplin et al. (2010) published observations of three bright G-type stars, which were monitored during the first 33.5 days of science operations. One of these stars, the subgiant KIC 11026764, exhibits a characteristic pattern of oscillation frequencies suggesting that it has evolved significantly. We have derived asteroseismic estimates of the properties of KIC 11026764 from Kepler photometry combined with ground-based spectroscopic data. We present the results of detailed modeling for this star, employing a variety of independent codes and analyses that attempt to match the asteroseismic and spectroscopic constraints simultaneously. We determine both the radius and the age of KIC 11026764 with a precision near 1%, and an accuracy near 2% for the radius and 15% for the age. Continued observations of this star promise to reveal additional oscillation frequencies that will further improve the determination of its fundamental properties., Comment: 16 pages, 6 figures, 4 tables, ApJ in press
Published: 2010
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33. Multiwavelength Observations of Small-Scale Reconnection Events triggered by Magnetic Flux Emergence in the Solar Atmosphere

Author: L. R. Bellot Rubio, Salvo L. Guglielmino, Guillaume Aulanier, S. Kamio, S. Vargas Domínguez, Francesca Zuccarello, Università degli studi di Catania = University of Catania (Unict), Instituto de Astrofisica de Andalucia, CSIC (IAA), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Physique solaire, 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)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, University College of London [London] (UCL), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), and Max-Planck-Gesellschaft
Subjects: Physics, Sun: magnetic topology, Field (physics), Field line, Astrophysics::High Energy Astrophysical Phenomena, Sun: chromosphere, Flux, FOS: Physical sciences, Astronomy and Astrophysics, Magnetic reconnection, Astrophysics, Magnetic flux, Atmosphere, Atmosphere of Earth, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Sun: activity, Physics::Space Physics, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Event (particle physics), Solar and Stellar Astrophysics (astro-ph.SR)
Abstract: The interaction between emerging magnetic flux and the pre-existing ambient field has become a "hot" topic for both numerical simulations and high-resolution observations of the solar atmosphere. The appearance of brightenings and surges during episodes of flux emergence is believed to be a signature of magnetic reconnection processes. We present an analysis of a small-scale flux emergence event in NOAA 10971, observed simultaneously with the Swedish 1-m Solar Telescope on La Palma and the \emph{Hinode} satellite during a joint campaign in September 2007. Extremely high-resolution G-band, H$\alpha$, and \ion{Ca}{2} H filtergrams, \ion{Fe}{1} and \ion{Na}{1} magnetograms, EUV raster scans, and X-ray images show that the emerging region was associated with chromospheric, transition region and coronal brightenings, as well as with chromospheric surges. We suggest that these features were caused by magnetic reconnection at low altitude in the atmosphere. To support this idea, we perform potential and linear force-free field extrapolations using the FROMAGE service. The extrapolations show that the emergence site is cospatial with a 3D null point, from which a spine originates. This magnetic configuration and the overall orientation of the field lines above the emerging flux region are compatible with the structures observed in the different atmospheric layers, and remain stable against variations of the force-free field parameter. Our analysis supports the predictions of recent 3D numerical simulations that energetic phenomena may result from the interaction between emerging flux and the pre-existing chromospheric and coronal field., Comment: In press for ApJ
Published: 2010
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34. The field high-amplitude SX Phe variable BL Cam: Results from a multisite photometric campaign: II. Evidence of a binary - Possibly triple - System

Author: M. Helvaci, M. Blauzek, V. Casanova, J. Michelet, G. Santacana, J. P. Sareyan, L. Kotková, A.-Y. Zhou, Hana Kučáková, S. Fauvaud, I. Scheggia, A. Avdibegovic, J. J. Rives, Petr Zasche, A. Nava-Vega, F. Fumagalli, M. Alvarez, C. Ulusoy, K. Truparová, J. Kliner, P. van Cauteren, B. Yasarsoy, Eric G. Hintz, Raoul Behrend, B. H. Granslo, L. Král, Cahit Yeşilyaprak, J. A. Farrell, S. Bartošíková, M. J. López-González, Patricia Lampens, M. Vilášek, Marek Wolf, F. Van Den Abbeel, G. Klingenberg, K. A. Graham, R. Kocián, I. Ribas, H. Wücher, Raul Michel, M. Fauvaud, John H. Simonetti, F. J. Aceituno, M. P. Nicholson, E. Rodriguez, J.-M. Vugnon, O. Trondal, L. Fox-Machado, Ege Üniversitesi, Observatoire du Bois de Bardon, Groupe européen d’observation stellaire (GEOS), Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Institut de Ciencies de l'Espai (ICE), Instituto de Astrofisica de Andalucia, CSIC (IAA), Koninklijke Sterrenwacht van België, Variable Star Section, Norwegian Astronomical Society, Sulphur Flats Observatory, Martin Observatory, Physics Dep., Virginia Polytechnic Institute & State University, Blacksburg, Astronomical Institute, Charles University, National Astronomical Observatoires-CAS, Observatorio Astronómico Nacional, Instituto de Astronomía, Universidad Nacional Autónoma de México, Facultad de Ciencias Químicas e Ingeniería, Universidad Autónoma de Baja California, Societá Astronomica Le pleiadi, Observatoire des Trois Korrigans, Department of Physics and Astronomy, Brigham Young University, Beersel Hills Observatory, Department of Physics, Akdeniz University, Department of Physics, Ataturk University, American Association of Variable Star Observers (AAVSO), Project Eridanus, Observatory and Planetarium of Johann Palisa, Club d'Astronomie Lyon Ampéré [Vaulx-en-Velin] (CALA), Club Eclipse : Club d'Etudes du Ciel, de la Lune, des Instruments, des Planètes, du Soleil et des Etoiles..., Astronomical Institute, Academy of Sciences, Ege University Observatory, Vesqueville Observatory, and Observatoire Astronomique de l'Université de Genève
Subjects: Physics, Stars: individual: BL Camelopardalis, Stars: variables: ? Scuti, education.field_of_study, Cepheid variable, Population, Brown dwarf, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Stars, Orbit, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Stars: oscillations, Binaries: general, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Maxima, Instability strip, education, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Stellar evolution, Solar and Stellar Astrophysics (astro-ph.SR), Techniques: photometric
Abstract: Short-period high-amplitude pulsating stars of Population I ($\delta$ Sct stars) and II (SX Phe variables) exist in the lower part of the classical (Cepheid) instability strip. Most of them have very simple pulsational behaviours, only one or two radial modes being excited. Nevertheless, BL Cam is a unique object among them, being an extreme metal-deficient field high-amplitude SX Phe variable with a large number of frequencies. Based on a frequency analysis, a pulsational interpretation was previously given. aims heading (mandatory) We attempt to interpret the long-term behaviour of the residuals that were not taken into account in the previous Observed-Calculated (O-C) short-term analyses. methods heading (mandatory) An investigation of the O-C times has been carried out, using a data set based on the previous published times of light maxima, largely enriched by those obtained during an intensive multisite photometric campaign of BL Cam lasting several months. results heading (mandatory) In addition to a positive (161 $\pm$ 3) x 10$^{-9}$ yr$^{-1}$ secular relative increase in the main pulsation period of BL Cam, we detected in the O-C data short- (144.2 d) and long-term ($\sim$ 3400 d) variations, both incompatible with a scenario of stellar evolution. conclusions heading (mandatory) Interpreted as a light travel-time effect, the short-term O-C variation is indicative of a massive stellar component (0.46 to 1 M$_{\sun}$) with a short period orbit (144.2 d), within a distance of 0.7 AU from the primary. More observations are needed to confirm the long-term O-C variations: if they were also to be caused by a light travel-time effect, they could be interpreted in terms of a third component, in this case probably a brown dwarf star ($\geq$ 0.03 \ M$_{\sun}$), orbiting in $\sim$ 3400 d at a distance of 4.5 AU from the primary., Comment: 7 pages, 5 figures, accepted for publication in A&A
Published: 2010
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35. Asteroseismic analysis of the CoRoT \delta-Scuti star HD174936

Author: E. Rodríguez, Laure Lefèvre, Juan Carlos Suárez, Frédéric Baudin, A. García Hernández, Michel Auvergne, R. Garrido, Ennio Poretti, Susana Martín-Ruiz, A. Rolland, A. Moya, Eric Michel, Reza Samadi, Pedro J. Amado, A. Baglin, C. Catala, Instituto de Astrofisica de Andalucia, CSIC (IAA), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), INAF-Osservatorio Astronomico di Brera (INAF-OAB), Institut d'astrophysique spatiale (IAS), and Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES)
Subjects: Physics, Oscillation, Astronomy and Astrophysics, Astrophysics, Star (graph theory), Light curve, Software package, Frequency spectrum, Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics::Solar and Stellar Astrophysics, Limit (mathematics), Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: We present an analysis of the \delta-Scuti star object HD 174936 (ID 7613) observed by CoRoT during the first short run SRc01 (27 days). A total number of 422 frequencies we are extracted from the light curve using standard prewhitening techniques. This number of frequencies was obtained by considering a spectral significance limit of sig = 10 using the software package SigSpec. Our analysis of the oscillation frequency spectrum reveals a spacing periodicity of around 52 \muHz. Although modes considered here are not in the asymptotic regime, a comparison with stellar models confirms that this signature may stem from a quasi-periodic pattern similar to the so-called large separation in solar-like stars., Comment: 7 pages, 7 figures, 2 tables. Accepted for publication in A&A CoRoT Special Feature
Published: 2009
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36. The asteroseismic ground-based observational counterpart of CoRoT

Author: Uytterhoeven, K., Poretti, E., Mathias, P., Amado, P. J., Rainer, M., Martin-Ruiz, S., Rodriguez, E., Paparo, M., Pollard, K., Maceroni, C., Balaguer-Nunoz, L., Ribas, I., Catala, C., Neiner, C., Garcia, R. A., Group, the CoRoT/SWG Ground-based Observations Working, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), INAF-Osservatorio Astronomico di Brera (INAF-OAB), Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA), Laboratoire d'Astrophysique de l'Observatoire Midi-Pyrénées (LATT), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Instituto de Astrofisica de Andalucia, CSIC (IAA), Konkoly Observatory, Research Center for Astronomy and Earth Sciences, University of Canterbury [Christchurch], INAF-Osservatorio Astronomico di Roma (INAF-OAR), DAM. Universitat de Barcelona, Diagonal 647, 08028, Barcelona, Spain, Institut d'Estudis Espacials de Catalunya (IEEC), Edif. Nexus, C/Gran Capità, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Galaxies, Etoiles, Physique, Instrumentation (GEPI), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Physique stellaire et galactique, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-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 Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Guzik, Joyce Ann, Bradley, and Paul A.
Subjects: Physics, Astrophysics - Solar and Stellar Astrophysics, Physics::Space Physics, Astrophysics::Instrumentation and Methods for Astrophysics, FOS: Physical sciences, Astrophysics::Solar and Stellar Astrophysics, Observational study, Satellite, Astrophysics, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Solar and Stellar Astrophysics (astro-ph.SR)
Abstract: We present different aspects of the ground-based observational counterpart of the CoRoT satellite mission. We give an overview of the selected asteroseismic targets, the numerous instruments and observatories involved, and the first scientific results., 3 pages, 2 tables, 1 figure, to be published in the conference proceedings 'Stellar Pulsation: Challenges for Theory and Observation' (31 May - 5 June, Santa Fe, New Mexico, US), publishers: American Institute of Physics
Published: 2009
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37. The B0.5 IVe CoRoT target HD 49330. II. Spectroscopic ground-based observations

Author: Marcelo Emilio, F. Espinosa Lara, Ennio Poretti, K. Uytterhoeven, A. L. Huat, C. Catala, Yves Fremat, Juan Fabregat, B. Leroy, Eduardo Janot-Pacheco, L. Andrade, Coralie Neiner, Juan Gutiérrez-Soto, Anne-Marie Hubert, Diana Fabiola Flores Diaz, Christophe Martayan, J. Suso, M. Floquet, P. D. Diago, B. de Batz, Monica Rainer, Pedro J. Amado, T. Semaan, Galaxies, Etoiles, Physique, Instrumentation (GEPI), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Physique stellaire et galactique, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-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 Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Observatoire Royal de Belgique (ORB), Universidad de São Paulo, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, INAF-Osservatorio Astronomico di Brera (INAF-OAB), Instituto de Astrofisica de Andalucia, CSIC (IAA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Universitat de València (UV), and Obervatório Astronômico, Universidade Estadual de Ponta Grossa
Subjects: Physics, Be star, Phase (waves), Astronomy, Astronomy and Astrophysics, Context (language use), Astrophysics, Star (graph theory), Stars, Space and Planetary Science, Emission spectrum, High order, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Line (formation)
Abstract: International audience; Context: We present spectroscopic ground-based observations of the early Be star HD 49330 obtained simultaneously with the CoRoT-LRA1 run just before the burst observed in the CoRoT data. Aims: Ground-based spectroscopic observations of the early Be star HD 49330 obtained during the precursor phase and just before the start of an outburst allow us to disantangle stellar and circumstellar contributions and identify modes of stellar pulsations in this rapidly rotating star. Methods: Time series analysis (TSA) is performed on photospheric line profiles of He I and Si III by means of the least squares method. Results: We find two main frequencies f1 = 11.86 c d-1 and f2 = 16.89 c d-1 which can be associated with high order p-mode pulsations. We also detect a frequency f3 = 1.51 c d-1 which can be associated with a low order g-mode. Moreover we show that the stellar line profile variability changed over the spectroscopic run. These results are in agreement with the results of the CoRoT data analysis, as shown in Huat et al. (2009). Conclusions: Our study of mid- and short-term spectroscopic variability allows the identification of p- and g-modes in HD 49330. It also allows us to display changes in the line profile variability before the start of an outburst. This brings new constraints for the seimic modelling of this star.
Published: 2009
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38. Pulsations in the late-type Be star HD 50 209 detected by CoRoT

Author: C. Martayan, B. de Batz, C. Catala, C. Neiner, E. Poretti, R. Garrido, Juan Gutiérrez-Soto, Juan Fabregat, M. Rainer, F. Espinosa-Lara, M. Floquet, B. Leroy, A. L. Huat, E. Michel, P. D. Diago, Eduardo Janot-Pacheco, L. Andrade, R. Samadi, M. Auvergne, Yves Fremat, Marcelo Emilio, T. Semaan, Anne-Marie Hubert, J. Suso, K. Uytterhoeven, Universitat de València (UV), Galaxies, Etoiles, Physique, Instrumentation (GEPI), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Physique stellaire et galactique, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-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 Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Observatoire Royal de Belgique (ORB), Instituto de Astrofisica de Andalucia, CSIC (IAA), Departamento de Astronomia Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Universidade de São Paulo, Obervatório Astronômico, Universidade Estadual de Ponta Grossa, and INAF-Osservatorio Astronomico di Brera (INAF-OAB)
Subjects: Rotation period, Be star, Hertzsprung–Russell diagram, FOS: Physical sciences, Astrophysics, Star (graph theory), 01 natural sciences, Spectral line, symbols.namesake, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Physics, 010308 nuclear & particles physics, Astronomy and Astrophysics, Light curve, Ciència Ensenyament, Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astronomia, symbols, Astrophysics::Earth and Planetary Astrophysics, Instability strip, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: The presence of pulsations in late-type Be stars is still a matter of controversy. It constitutes an important issue to establish the relationship between non-radial pulsations and the mass-loss mechanism in Be stars. To contribute to this discussion, we analyse the photometric time series of the B8IVe star HD 50209 observed by the CoRoT mission in the seismology field. We use standard Fourier techniques and linear and non-linear least squares fitting methods to analyse the CoRoT light curve. In addition, we applied detailed modelling of high-resolution spectra to obtain the fundamental physical parameters of the star. We have found four frequencies which correspond to gravity modes with azimuthal order m=0,-1,-2,-3 with the same pulsational frequency in the co-rotating frame. We also found a rotational period with a frequency of 0.679 \cd (7.754 $\mu$Hz). HD 50209 is a pulsating Be star as expected from its position in the HR diagram, close to the SPB instability strip., Comment: 7 pages, 8 figures, accepted fot publication in the A&A CoRoT special feature
Published: 2009
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39. Absolute dimensions of solar-type eclipsing binaries. III. EW Orionis. Stellar evolutionary models tested by a G0V system

Author: J. V. Clausen, E. H. Olsen, B. E. Helt, A. Claret, H. Bruntt, Niels Bohr Institute, Sydney Institute for Astronomy (SIfA), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Astronomie du LESIA, 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)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Instituto de Astrofisica de Andalucia, CSIC (IAA)
Subjects: Physics, Apsidal precession, chemistry.chemical_element, Binary number, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Standard Model, Orbit, Stars, chemistry, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Helium, Astrophysics::Galaxy Astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Envelope (waves), Open cluster
Abstract: We present a detailed study of the G0V detached eclipsing binary EW Ori, based on new photometric and spectroscopic observations. Masses and radii that are precise to 0.9% and 0.5%, respectively, have been established for both components. The 1.12 Msun secondary component reveals weak Ca II H and K emission and is probably mildly active; no signs of activity are seen for the 1.17 Msun primary. We derive an [Fe/H] abundance of +0.05 +/- 0.09 and similar abundances for Si, Ca, Sc, Ti, Cr, and Ni. Yonsai-Yale and Granada solar-scaled evolutionary models for the observed metal abundance reproduce the components fairly well at an age of approx. 2 Gyr. Perfect agreement is, however, obtained at an age of 2.3 Gyr for a combination of a) a slight downwards adjustment of the envelope mixing length parameter for the secondary, as seen for other active solar-type stars, and b) a slightly lower helium content than prescribed by the Y-Z relations adopted for the standard model grids. The orbit is eccentric (e = 0.0758 +/- 0.0020), and apsidal motion with a 62% relativistic contribution has been detected. The apsidal motion period is U = 16300 +/- 3900 yr, and the inferred mean central density concentration coefficient, log(k_2) = -1.66 +/- 0.30, agrees marginally with model predictions. The measured rotational velocities, 9.0 +/- 0.7 (primary) and 8.8 +/- 0.6 (secondary) km/s, are in agreement with both the synchronous velocities and the theoretically predicted pseudo-synchronous velocities. Finally, the distance (175 +/- 7 pc), age, and center-of mass velocity (6 km/s) exclude suggested membership of the open cluster Collinder 70. EW Ori now belongs to the small group of solar-type eclipsing binaries with well-established astrophysical properties., Comment: Accepted for publication in Astronomy and Astrophysics
Published: 2009
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40. Emergence of Small-scale Magnetic Loops Through the Quiet Solar Atmosphere

Author: M. J. Martínez González, L. R. Bellot Rubio, Instituto de Astrofísica de Canarias (IAC), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), and Instituto de Astrofisica de Andalucia, CSIC (IAA)
Subjects: Physics, Brightness, Photosphere, Linear polarization, Granule (solar physics), Dutch Open Telescope, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Degree of coherence, Magnetic flux, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Chromosphere, Solar and Stellar Astrophysics (astro-ph.SR)
Abstract: We investigate the emergence of magnetic flux in the quiet Sun at very small spatial scales, focusing on the magnetic connection between the photosphere and chromosphere. The observational data consist of spectropolarimetric measurements and filtergrams taken with the Hinode satellite and the Dutch Open Telescope. We find that a significant fraction of the magnetic flux present in internetwork regions appears in the form of Omega-shaped loops. The emergence rate is 0.02 loops per hour and arcsec^{-2}, which brings 1.1 x 10^12 Mx s^{-1} arcsec^{-2} of new flux to the solar surface. Initially, the loops are observed as small patches of linear polarization above a granular cell. Shortly afterwards, two footpoints of opposite polarity become visible in circular polarization within or at the edges of the granule and start to move toward the adjacent intergranular space. The orientation of the footpoints does not seem to obey Hale's polarity rules. The loops are continuously buffeted by convective motions, but they always retain a high degree of coherence. Interestingly, 23% of the loops that emerge in the photosphere reach the chromosphere (16 cases out of 69). They are first detected in Fe I 630 nm magnetograms and 5 minutes later in Mg I b 517.3 nm magnetograms. After about 8 minutes, some of them are also observed in Ca II H line-core images, where the footpoints produce small brightness enhancements., Accepted for publication in ApJ
Published: 2009
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41. HD 51106 and HD 50747: an ellipsoidal binary and a triple system observed with CoRoT

Author: J. C. Valtier, K. Uytterhoeven, N. Dolez, R. Samadi, C. Catala, A. Hui Bon Hua, P. Mathias, E. Poretti, G. Vauclair, M. Auvergne, E. Michel, M. Rainer, Pedro J. Amado, D. Le Contel, Sylvie Vauclair, A. Baglin, Laboratoire Astrophysique de Toulouse-Tarbes (LATT), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Hippolyte Fizeau (FIZEAU), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), INAF-Osservatorio Astronomico di Brera (INAF-OAB), Instituto de Astrofisica de Andalucia, CSIC (IAA), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: Physics, Oscillation, Triple system, FOS: Physical sciences, Binary number, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Star (graph theory), Light curve, Stars, symbols.namesake, Fourier transform, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, symbols, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Variable star, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics
Abstract: We present an analysis of the observations of HD 51106 and HD 50747 by the satellite CoRoT, obtained during its initial run, and of the spectroscopic preparatory observations. AIMS: We complete an analysis of the light curve, extract the main frequencies observed, and discuss some preliminary interpretations about the stars. Methods: We used standard Fourier transform and pre-whitening methods to extract information about the periodicities of the stars. Results: HD 51106 is an ellipsoidal binary, the light curve of which can be completely explained by the tidal deformation of the star and smaller secondary effects. HD 50747 is a triple system containing a variable star, which exhibits many modes of oscillation with periods in the range of a few hours. On the basis of this period range and the analysis of the physical parameters of the star, we conclude that HD 50747 is a Gamma-Doradus star., Comment: 7 pages, 8 figures, use (Astronomy-Astrophysics format/macro LAtex)
Published: 2009
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42. Molecular Gas in NUclei of GAlaxies (NUGA). X. The Seyfert 2 galaxy NGC 3147

Author: Stephane Leon, Santiago García-Burillo, Francoise Combes, Leslie K. Hunt, Andrew J. Baker, Viviana Casasola, Università degli Studi di Padova = University of Padua (Unipd), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Galaxies et cosmologie, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Observatorio Astronomico Nacional, Madrid, Istituto di Radioastronomia, Firenze, Instituto de Astrofisica de Andalucia, CSIC (IAA), and Department of Physics and Astronomy, State University of New Jersey
Subjects: Angular momentum, active [Galaxies], FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, law.invention, Telescope, law, ISM [Galaxies], Astrophysics::Galaxy Astrophysics, Galaxies: nuclei, Physics, spiral [Galaxies], Spiral galaxy, Star formation, kinematics and dynamics [Galaxies], Image (category theory), Astrophysics (astro-ph), Galaxies: kinematics and dynamics, Resonance, Astronomy and Astrophysics, Galaxies: active, individual: NGC3147 [Galaxies], Galaxy, Galaxies: ISM, Space and Planetary Science, nuclei [Galaxies], Astrophysics::Earth and Planetary Astrophysics, Galaxies: individual: NGC3147, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Galaxies: spiral, Bar (unit)
Abstract: We present 12CO(1-0) and 12CO(2-1) observations of the SA(rs)bc Seyfert 2 galaxy NGC 3147, obtained with the IRAM interferometer at 1.9′ x 1.6′′ and 1.6′′ x 1.4′′ resolutions, respectively. We have also observed the central region of NGC3147 with the IRAM 30m telescope (at resolutions of 22′′ and 12′′ for 12CO(1-0) and 12CO(2-1), respectively), in order to obtain complete sampling at low spatial frequencies. These observations have been made in the context of the NUclei of GAlaxies (NUGA) project, aimed at the study of the different mechanisms for gas fueling of active galactic nuclei (AGN). A central peak seen mainly in 12CO(2-1) and a ring-like structure at r ~ 10′′ ~ 2 kpc dominate the 12CO maps. In 12CO(1-0) an outer spiral at r ~ 20′′ ~ 4 kpc is also detected, not visible in 12CO(2-1) emission because it falls outside the field-of-view of the primary beam. The average I21/I10 line ratio is ∼ 0.7 in temperature units over the region mapped in both lines, consistent with the optically thick emission expected in the nuclei of spiral galaxies. The kinematics of the molecular structures are quite regular, although there is evidence for local non-circular or streaming motions. We show that the molecular gas distribution is similar but not exactly identical to those of star formation tracers, i.e., infrared (Spitzer) and ultraviolet (GALEX) emission. This agreement is consistent with a scenario of steady, ongoing formation of stars from the molecular clouds at a rate of ∼ 1 M⊙ yr−1 within the innermost 4 kpc in radius., Using a NIR image obtained with adaptive optics at the Canada-France-Hawaii Telescope (CFHT), we identify a weak bar in NGC 3147, which is classified as non-barred galaxy in the optical. We then compute the gravity torques exerted by this stellar bar on the gas. The torque is obtained first at each point in the map, and then azimuthally averaged with a weighting determined by the gas surface density traced by the CO emission. We find that the gas inside the inner CO ring is subject to a net negative torque and loses angular momentum. This is expected for gas at the ultra-harmonic resonance (UHR), just inside the corotation resonance of the stellar bar. In contrast, the gas outside corotation, in the spiral arms comprising the outer spiral structure, suffers positive torques and is driven outwards. We conclude that some molecular gas is presently flowing into the central region, since we find negative torques down to the resolution limit of our images., We thank the scientific and technical staff at IRAM for their work in making our 30m and PdBI observations possible. V. Casasola is pleased to acknowledge the hospitality and stimulating environment provided by the Observatoire de Paris-LERMA, where part of the work on this paper was done during her stay in Paris, thanks to the EARA agreement. In this work, we have made use of MAST/GALEX images and the Spitzer archive.
Published: 2008
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43. Molecular gas in NUclei of GAlaxies (NUGA). XI. A complete gravity torque map of NGC4579: new clues on bar evolution

Author: L. K. Hunt, M. Krips, Frederic Boone, S. Haan, Francoise Combes, Santiago García-Burillo, Eva Schinnerer, Isabel Márquez, S. Fernandez-Garcia, Observatorio Astronomico Nacional, Madrid, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Galaxies et cosmologie, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Istituto di Radioastronomia, Firenze, Max-Planck-Institut für Astronomie (MPIA), Center for Astrophysics, Harvard University, Cambridge - SMA project, and Instituto de Astrofisica de Andalucia, CSIC (IAA)
Subjects: Physics, Angular momentum, Gravity (chemistry), Spiral galaxy, Active galactic nucleus, Bar (music), Astrophysics (astro-ph), Plateau de Bure Interferometer, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Galaxy, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics::Galaxy Astrophysics, Line (formation)
Abstract: We create a complete gravity torque map of the disk of the LINER/Seyfert 1.9 galaxy NGC4579. We quantify the efficiency of angular momentum transport and search for signatures of secular evolution in the fueling process from r~15kpc down to the inner r~50pc around the Active Galactic Nucleus (AGN). We use both the 1-0 and 2-1 line maps of CO obtained with the Plateau de Bure Interferometer (PdBI) as part of the NUclei of Galaxies-(NUGA)-project. We derive the stellar potential from a NIR (K band) wide field image of the galaxy. The K-band image, which reveals a stellar bar, together with a high resolution HI map of NGC4579 obtained with the Very Large Array (VLA), allow us to extend the gravity torque analysis to the outer disk. The bulk of the gas response traced by the CO PdBI maps follows the expected gas flow pattern induced by the bar potential in the presence of two Inner Lindblad Resonances (ILR). We also detect an oval distortion in the inner r~200pc of the K-band image. The oval is not aligned with the large-scale bar, a signature of dynamical decoupling. The morphology of the outer disk suggests that the neutral gas is currently piling up in a pseudo-ring formed by two winding spiral arms that are morphologically decoupled from the bar structure. In the outer disk, the decoupling of the spiral allows the gas to efficiently produce net gas inflow on intermediate scales. The corotation barrier seems to be overcome due to secular evolution processes. The gas in the inner disk is efficiently funneled by gravity torques down to r~300pc. Closer to the AGN, the two m=2 modes (bar and oval) act in concert to produce net gas inflow down to r~50pc, providing a clear smoking gun evidence of fueling with associated short dynamical time-scales., Comment: Submitted for publication in A&A. 21 pages, 21 figures
Published: 2008
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44. filou oscillation code

Author: M. J. Goupil, Juan Carlos Suárez, Instituto de Astrofisica de Andalucia, CSIC (IAA), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Astronomie du LESIA, 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)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris
Subjects: Physics, Field (physics), Oscillation, Computation, Mathematical analysis, Astrophysics (astro-ph), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Space (mathematics), Space and Planetary Science, Differential rotation, Astrophysics::Earth and Planetary Astrophysics, Adiabatic process, Degeneracy (mathematics), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Rotation (mathematics)
Abstract: The present paper provides a description of the oscillation code FILOU, its main features, type of applications it can be used for, and some representative solutions. The code is actively involved in CoRoT/ESTA exercises (this volume) for the preparation for the proper interpretation of space data from the CoRoT mission. Although CoRoT/ESTA exercises have been limited to the oscillations computations for non-rotating models, the main characteristic of FILOU is, however, the computation of radial and non-radial oscillation frequencies in presence of rotation. In particular, FILOU calculates (in a perturbative approach) adiabatic oscillation frequencies corrected for the effects of rotation (up to the second order in the rotation rate) including near degeneracy effects. Furthermore, FILOU works with either a uniform rotation or a radial differential rotation profile (shellular rotation), feature which makes the code singular in the field., 6 pages, 5 figures. Astrophysics and Space Science (in press)
Published: 2008
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45. Star formation in isolated AMIGA galaxies: dynamical influence of bars

Author: Gilles Bergond, Lourdes Verdes-Montenegro, Francoise Combes, S. Verley, Stephane Leon, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Galaxies et cosmologie, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Instituto de Astrofisica de Andalucia, CSIC (IAA), Galaxies, Etoiles, Physique, Instrumentation (GEPI), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), and Instituto de Radio Astronomía Milimétrica (IRAM)
Subjects: Physics, Spiral galaxy, Star formation, media_common.quotation_subject, Astrophysics (astro-ph), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Star (graph theory), Galaxy, Universe, Interstellar medium, Stars, Space and Planetary Science, Amiga, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics::Galaxy Astrophysics, media_common
Abstract: Star formation depends strongly both on the local environment of galaxies, and on the internal dynamics of the interstellar medium. To disentangle the two effects, we obtained, in the framework of the AMIGA project, Ha and Gunn r photometric data for more than 200 spiral galaxies lying in very low-density regions of the local Universe. We characterise the Ha emission, tracing current star formation, of the 45 largest and less inclined galaxies observed for which we estimate the torques between the gas and the bulk of the optical matter. We could subsequently study the Ha morphological aspect of these isolated spiral galaxies. Using Fourier analysis, we focus on the modes of the spiral arms and also on the strength of the bars, computing the torques between the gas and newly formed stars (Ha) and the bulk of the optical matter (Gunn r). We interpret the various bar/spiral morphologies observed in terms of the secular evolution experienced by galaxies in isolation. We also classify the different spatial distributions of star forming regions in barred galaxies. The observed frequency of particular patterns brings constraints on the lifetime of the various evolution phases. We propose an evolutive sequence accounting for the transitions between the different phases we could observe. Isolated galaxies appear not to be preferentially barred or unbarred. Through numerical simulations, trying to fit the Ha distributions yields constraints on the star formation law, which is likely to differ from a genuine Schmidt law. In particular, it is probable that the relative velocity of the gas in the bar also needs to be taken into account., 15 pages, 9 figures (low resolution), 2 tables, accepted by A&A
Published: 2007
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46. The AMIGA sample of isolated galaxies. V. Quantification of the isolation

Author: Daniel Espada, S. Verley, Stephane Leon, Emilio José García, S. C. Odewahn, Ute Lisenfeld, Lourdes Verdes-Montenegro, J. Sabater, Gilles Bergond, J. W. Sulentic, Francoise Combes, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Galaxies et cosmologie, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Instituto de Astrofisica de Andalucia, CSIC (IAA), Instituto de Radio Astronomía Milimétrica (IRAM), Department of Astronomy, University of Alabama, Universidad de Granada = University of Granada (UGR), and McDonald Observatory, University of Texas
Subjects: Physics, Evolution, Sample (material), Astrophysics (astro-ph), FOS: Physical sciences, Formation, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Galaxies, Galaxy, Reference sample, Space and Planetary Science, Fundamental parameters, Tidal force, Amiga, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics::Galaxy Astrophysics
Abstract: Context.The AMIGA project aims to build a well defined and statistically significant reference sample of isolated galaxies in order to estimate the environmental effects on the formation and evolution of galaxies., Aims.The goal of this paper is to provide a measure of the environment of the isolated galaxies in the AMIGA sample, quantifying the influence of the candidate neighbours identified in our previous work and their potential effects on the evolution of the primary galaxies. Here we provide a quantification of the isolation degree of the galaxies in this sample., Methods.Our starting sample is the Catalogue of Isolated Galaxies (CIG). We used two parameters to estimate the influence exerted by the neighbour galaxies on the CIG galaxy: the local number density of neighbour galaxies and the tidal strength affecting the CIG galaxy. We show that both parameters together provide a comprehensive picture of the environment. For comparison, those parameters have also been derived for galaxies in denser environments such as triplets, groups and clusters., Results.The CIG galaxies show a continuous spectrum of isolation, as quantified by the two parameters, from very isolated to interacting. The fraction of CIG galaxies whose properties are expected to be influenced by the environment is however low (159 out of 950 galaxies). The isolated parameters derived for the comparison samples gave higher values than for the CIG and we found clear differences for the average values of the 4 samples considered, proving the sensitivity of these parameters., Conclusions.The environment of the galaxies in the CIG has been characterised, using two complementary parameters quantifying the isolation degree, the local number density of the neighbour galaxies and the tidal forces affecting the isolated galaxies. A final catalogue of galaxies has been produced and the most isolated of these galaxies are consequently appropriate to serve as a reference sample for the AMIGA project., This work has been partially supported by DGI Grant AYA 2005-07516-C02-01 and the Junta de Andalucía (Spain). U.L. acknowledges support by the research project ESP 2004-06870-C02-02. Jack Sulentic is partially supported by a sabbatical grant SAB2004-01-04 of the Spanish Ministerio de Educación y Ciencias. GB acknowledges support at the IAA/CSIC by an I3P contract (I3P-PC2005F) funded by the European Social Fund.
Published: 2007
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47. Mode stability in delta Scuti stars: linear analysis versus observations in open clusters

Author: F. Perez Hernandez, G. Houdek, E. Michel, Yveline Lebreton, Juan Carlos Suárez, Instituto de Astrofisica de Andalucia, CSIC (IAA), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Astronomie du LESIA, 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)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Institute of Astronomy, University of Cambridge (IoA), Instituto de Astrofísica de Canarias (IAC), Galaxies, Etoiles, Physique, Instrumentation (GEPI), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Physique stellaire et galactique, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-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)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, Standard solar model, Oscillation, Astrophysics (astro-ph), Mode (statistics), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Rotation, Stability (probability), Stars, Space and Planetary Science, Astrophysics::Solar and Stellar Astrophysics, Adiabatic process, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Open cluster
Abstract: A comparison between linear stability analysis and observations of pulsation modes in five delta Scuti stars, belonging to the same cluster, is presented. The study is based on the work by Michel et al. (1999), in which such a comparison was performed for a representative set of model solutions obtained independently for each individual star considered. In this paper we revisit the work by Michel et al. (1999) following, however, a new approach which consists in the search for a single, complete, and coherent solution for all the selected stars, in order to constrain and test the assumed physics describing these objects. To do so, refined descriptions for the effects of rotation on the determination of the global stellar parameters and on the adiabatic oscillation frequency computations are used. In addition, a crude attempt is made to study the role of rotation on the prediction of mode instabilities.The present results are found to be comparable with those reported by Michel et al. (1999). Within the temperature range log T_eff = 3.87-3.88 agreement between observations and model computations of unstable modes is restricted to values for the mixing-length parameter alpha_nl less or equal to 1.50. This indicates that for these stars a smaller value for alpha_nl is required than suggested from a calibrated solar model. We stress the point that the linear stability analysis used in this work still assumes stellar models without rotation and that further developments are required for a proper description of the interaction between rotation and pulsation dynamics., 8 pages, 4 figures, 3 tables. (MNRAS, in press)
Published: 2007
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48. The AMIGA sample of isolated galaxies. IV. A catalogue of neighbours around isolated galaxies

Author: Stephane Leon, Francoise Combes, S. C. Odewahn, Daniel Espada, Ute Lisenfeld, J. Sabater, Emilio José García, S. Verley, Lourdes Verdes-Montenegro, J. W. Sulentic, Gilles Bergond, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Galaxies et cosmologie, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Instituto de Astrofisica de Andalucia, CSIC (IAA), McDonald Observatory, University of Texas, Instituto de Radio Astronomía Milimétrica (IRAM), Department of Astronomy, University of Alabama, and Universidad de Granada = University of Granada (UGR)
Subjects: Physics, education.field_of_study, Evolution, Sample (material), Astrophysics (astro-ph), Population, FOS: Physical sciences, Formation, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Galaxies, Redshift, Galaxy, Quantitative measure, Interstellar medium, Space and Planetary Science, Fundamental parameters, Amiga, Degree of confidence, education, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics::Galaxy Astrophysics
Abstract: Context.Studies of the effects of environment on galaxy properties and evolution require well defined control samples. Such isolated galaxy samples have up to now been small or poorly defined. The AMIGA project (Analysis of the interstellar Medium of Isolated GAlaxies) represents an attempt to define a statistically useful sample of the most isolated galaxies in the local (z $\leq$ 0.05) Universe., Aims.A suitable large sample for the AMIGA project already exists, the Catalogue of Isolated Galaxies (CIG, Karachentseva, 1973, Astrofizicheskie Issledovaniia Izvestiya Spetsial'noj Astrofizicheskoj Observatorii, 8, 3; 1050 galaxies), and we use this sample as a starting point to refine and perform a better quantification of its isolation properties., Methods.Digitised POSS-I E images were analysed out to a minimum projected radius R $\geq$ 0.5 Mpc around 950 CIG galaxies (those within Vr = 1500 km s-1 were excluded). We identified all galaxy candidates in each field brighter than B = 17.5 with a high degree of confidence using the LMORPHO software. We generated a catalogue of approximately 54 000 potential neighbours (redshifts exist for $\approx$30% of this sample)., Results.Six hundred sixty-six galaxies pass and two hundred eighty-four fail the original CIG isolation criterion. The available redshift data confirm that our catalogue involves a largely background population rather than physically associated neighbours. We find that the exclusion of neighbours within a factor of four in size around each CIG galaxy, employed in the original isolation criterion, corresponds to $\Delta V_r \approx$ 18 000 km s-1 indicating that it was a conservative limit., Conclusions.Galaxies in the CIG have been found to show different degrees of isolation. We conclude that a quantitative measure of this is mandatory. It will be the subject of future work based on the catalogue of neighbours obtained here., This work has been partially supported by DGI Grant AYA 2005-07516-C02-01 and the Junta de Andalucía (Spain). UL acknowledges support by the research project ESP 2004-06870-C02-02. Jack Sulentic is partially supported by a sabbatical grant SAB2004-01-04 of the Spanish Ministerio de Educación y Ciencias. G.B. acknowledges support at the IAA/CSIC by an I3P contract (I3P-PC2005F) funded by the European Social Fund.
Published: 2007
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49. Properties of the dust cloud caused by the Deep Impact experiment

Author: Laurent Jorda, P. L. Lamy, P. J. Gutierrez, L. M. Lara, Detlef Koschny, Stubbe F. Hviid, Michael Küppers, G. Faury, J. Lecacheux, H. U. Keller, Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Research and Scientific Support Department, ESA-ESTEC (RSSD), Observatoire de Paris, Université Paris sciences et lettres (PSL), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Planétologie du LESIA, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), and Instituto de Astrofisica de Andalucia, CSIC (IAA)
Subjects: Physics, Range (particle radiation), Solar System, Monte Carlo method, Comet, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Kinetic energy, Spherical model, Space and Planetary Science, Particle-size distribution, Astrophysics::Earth and Planetary Astrophysics, Ejecta, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics::Galaxy Astrophysics
Abstract: We present an analysis of the observations of the Deep Impact event performed by the OSIRIS narrow angle camera aboard the Rosetta spacecraft over two weeks, in an effort to characterize the cometary dust grains ejected from the nucleus of Comet 9P/Tempel 1. We adopt a Monte Carlo approach to generate calibrated synthetic images, and a linear combination of them is fitted to the calibrated images so as to determine the physical parameters of the dust cloud. Our model considers spherical olivine particles with a density of 3780 kg m −3 . It incorporates constraints on the direction of the cone of emission coming from additional images obtained at Pic du Midi observatory, and constraints on the dust terminal velocities coming from the physics of the impact. We find that the slope of the differential dust size distribution of grains with radii β > 0.008 ) is 3.1 ± 0.3 , a value typical of cometary dust tails. This shows that there is no evidence in our data for an enhancement in sub-micron particles in the ejecta compared to the typical dust distribution of active comets. We estimate the mass of particles with radii β > 0.14 ) to be 1.5 ± 0.2 × 10 5 kg . These particles represent more than 80% of the cross-section of the observed dust cloud. The mass carried by larger particles depends whether the gas significantly increases the kinetic energy of the grains in the inner coma; it lies in the range 1 – 14 × 10 6 kg for particles with radii β > 0.002 ). We obtain the distribution of terminal velocities reached by the dust after the dust–gas interaction which is very well constrained between 10 and 600 m s −1 . It is characterized by Gaussian with a maximum at about 190 m s −1 and a width at half maximum of 150 m s −1 .
Published: 2007
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50. Multisite campaign on the open cluster M67 - III. delta Scuti pulsations in the blue stragglers

Author: Róbert Szabó, H. Kjeldsen, M. Y. Bouzid, T. H. Dall, C. Sterken, László L. Kiss, J.-R. Koo, Timothy R. Bedding, S. L. Kim, S. Frandsen, C.-U. Lee, Juan Carlos Suárez, H. Bruntt, Jeong Ae Lee, Z. Csubry, R. L. Gilliland, J. Nuspl, D. Stello, A. P. Jacob, Torben Arentoft, Y. B. Kang, Z. E. Dind, Henrik Jeldtoft Jensen, School of physics, University of New South Wales, Instituto de Astrofisica de Andalucia, CSIC (IAA), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Institute for Physics and Astronomy, University of Århus, Université Libre de Bruxelles, Konkoly Observatory, Research Center for Astronomy and Earth Sciences, Gemini Observatory, Space Telescope Science Institute (STScI), Department of Astronomy and Space Science, Chungnam National University, and Korea Astronomy and Space Science Institute (KASI)
Subjects: Delta, Physics, Astrophysics (astro-ph), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Blue straggler, Photometry (optics), Stars, Amplitude, Space and Planetary Science, Excited state, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Spectroscopy, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics::Galaxy Astrophysics, Open cluster
Abstract: We have made an asteroseismic analysis of the variable blue stragglers in the open cluster M67. The data set consists of photometric time series from eight sites using nine 0.6-2.1 meter telescopes with a time baseline of 43 days. In two stars, EW Cnc and EX Cnc, we detect the highest number of frequencies (41 and 26) detected in delta Scuti stars belonging to a stellar cluster, and EW Cnc has the second highest number of frequencies detected in any delta Scuti star. We have computed a grid of pulsation models that take the effects of rotation into account. The distribution of observed and theoretical frequencies show that in a wide frequency range a significant fraction of the radial and non-radial low-degree modes are excited to detectable amplitudes. Despite the large number of observed frequencies we cannot constrain the fundamental parameters of the stars. To make progress we need to identify the degrees of some of the modes either from multi-colour photometry or spectroscopy., Comment: 15 pages, 14 figs, one appendix. Part three in a series of papers describing results from an extensive multi-site campaign on the open cluster M67
Published: 2007
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