Author: "Université de Cergy Pontoise (UCP)" / Publisher: american astronomical society - Searchworks@Jio Institute Digital Library Search Results

Your search keyword '"Université de Cergy Pontoise (UCP)"' showing total 90 results

Start Over Author "Université de Cergy Pontoise (UCP)" Publisher american astronomical society

90 results on '"Université de Cergy Pontoise (UCP)"'

1. The Close AGN Reference Survey (CARS): SOFIA detects spatially-resolved [C II] emission in the luminous AGN HE0433-1028

Author: Bernd Husemann, Timothy A. Davis, J. Scharwächter, Francoise Combes, R. McElroy, Massimo Gaspari, C. Fischer, Christopher P. O'Dea, Stefi A. Baum, Andreas Eckart, Scott M. Croom, Grant R. Tremblay, I. Smirnova-Pinchukova, Tanya Urrutia, Nastaran Fazeli, Meredith Powell, Gerold Busch, Randolf Klein, Miguel A. Pérez-Torres, Álvaro Sánchez-Monge, Mirko Krumpe, German Research Foundation, Ministerio de Economía y Competitividad (España), European Commission, Natural Sciences and Engineering Research Council of Canada, National Aeronautics and Space Administration (US), German Centre for Air and Space Travel, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Chaire Galaxies et cosmologie, Collège de France (CdF (institution)), INAF - Osservatorio Astrofisico di Arcetri (OAA), Istituto Nazionale di Astrofisica (INAF), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris), 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), and Leibniz Institute for Astrophysics Potsdam (AIP)
Subjects: Active galactic nucleus, active [Galaxies], Galaxies: individual (HE 0433-1028), Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, individual (HE 0433-1028) [Galaxies], 01 natural sciences, Luminosity, 010309 optics, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Spectroscopy, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, Astrophysics::Galaxy Astrophysics, Line (formation), Physics, [PHYS]Physics [physics], Stratospheric Observatory for Infrared Astronomy, Star formation, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy and Astrophysics, Galaxies: active, Multi Unit Spectroscopic Explorer, Astrophysics - Astrophysics of Galaxies, Redshift, starburst [Galaxies], 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Galaxies: starburst
Abstract: We report spatially resolved [C ii] λ158 μm observations of HE 0433-1028, which is the first detection of a nearby luminous active galactic nucleus (AGN; redshift 0.0355) with the Field-Imaging Far-Infrared Line Spectrometer (FIFI-LS) on board the airborne Stratospheric Observatory For Infrared Astronomy (SOFIA). We compare the spatially resolved star formation tracers [C ii], as provided by our SOFIA observations, and Hα from the Multi Unit Spectroscopic Explorer (MUSE) optical integral-field spectroscopy. We find that the [C ii] emission is mainly matching the extended star formation as traced by the extinction-corrected Hα line emission but some additional flux is present. While a larger sample is needed to statistically confirm our findings and investigate possible dependencies on AGN luminosity and star formation rate, our study underlines the necessity of collecting a spatially resolved optical-far-infrared data set for nearby AGNs, and shows that it is technically feasible to collect such data sets with FIFI-LS on board SOFIA. © 2018. The American Astronomical Society. All rights reserved., Based in part on observations made with the NASA/DLR Stratospheric Observatory for Infrared Astronomy (SOFIA). SOFIA is jointly operated by the Universities Space Research Association, Inc. (USRA), under NASA contract NAS2-97001, and the Deutsches SOFIA Institut (DSI) under DLR contract 50 OK 0901 to the University of Stuttgart. We thank the anonymous referee for a constructive report that helped to clarify the manuscript. This work was supported by the Deutsche Forschungsgemeinschaft (DFG) via SFB 956, subprojects A2, and A6. The work of S.B. and C.O. was supported by NSERC (Natural Sciences and Engineering Research Council of Canada). M.G. is supported by NASA through Einstein Postdoctoral Fellowship Award No. PF5-160137 issued by the Chandra X-ray Observatory Center, which is operated by the SAO for and on behalf of NASA under contract NAS8-03060. Support for this work was also provided by Chandra grant GO7-18121X. M.K. acknowledges support by DLR 50OR1802. M.P.T. acknowledges support from the Spanish MINECO through grants AYA2012-38491-C02-02 and AYA2015-63939-C2-1-P.
Published: 2018
Full Text: View/download PDF

2. Multiple Stellar Flybys Sculpting the Circumstellar Architecture in RW Aurigae

Author: Thomas J. Haworth, Stefano Facchini, William R. F. Dent, Cathie J. Clarke, Richard A. Booth, Sylvie Cabrit, Joseph E. Rodriguez, Keivan G. Stassun, Ryan A. Loomis, Eric L. N. Jensen, Jérôme Pety, Catherine Dougados, Rodriguez, JE [0000-0001-8812-0565], Loomis, R [0000-0002-8932-1219], Cabrit, S [0000-0002-1593-3693], Facchini, S [0000-0003-4689-2684], Jensen, ELN [0000-0002-4625-7333], Stassun, KG [0000-0002-3481-9052], Pety, J [0000-0003-3061-6546], Apollo - University of Cambridge Repository, Harvard-Smithsonian Center for Astrophysics (CfA), Harvard University [Cambridge]-Smithsonian Institution, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Imperial College London, Laboratoire d'Informatique et Systèmes (LIS), Aix Marseille Université (AMU)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Interdisciplinary Centre for Security, Reliability and Trust [Luxembourg] (SnT), Université du Luxembourg (Uni.lu), University of Cambridge [UK] (CAM), Vanderbilt University [Nashville], Joint ALMA Observatory (JAO), European Southern Observatory (ESO)-National Radio Astronomy Observatory (NRAO), Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), Booth, Richard [0000-0002-0364-937X], Clarke, Catherine [0000-0003-4288-0248], Harvard University-Smithsonian Institution, 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 Cergy Pontoise (UCP), and Université Paris-Seine-Université Paris-Seine-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: OPHIUCHUS, astro-ph.SR, 0306 Physical Chemistry (Incl. Structural), T-TAURI STARS, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Astronomy & Astrophysics, 0305 Organic Chemistry, 01 natural sciences, AUR, FORMING REGIONS, YOUNG STARS, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Architecture, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), ComputingMilieux_MISCELLANEOUS, Astrophysics::Galaxy Astrophysics, Physics, [PHYS]Physics [physics], Science & Technology, 010308 nuclear & particles physics, protoplanetary disks, Astronomy, Astronomy and Astrophysics, VELOCITY, BINARY-SYSTEMS, VARIABILITY, 0201 Astronomical And Space Sciences, Astrophysics - Solar and Stellar Astrophysics, binaries: general, Space and Planetary Science, ACCRETION DISK, IMAGING SURVEY, Physical Sciences, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], stars: individual (RW Aur)
Abstract: We present high-resolution ALMA Band 6 and 7 observations of the tidally disrupted protoplanetary disks of the RW Aurigae binary. Our observations reveal the presence of additional tidal streams to the previously observed tidal arm around RW Aur A. The observed configuration of tidal streams surrounding RW Aur A and B is incompatible with a single star--disk tidal encounter, suggesting that the RW Aurigae system has undergone multiple fly-by interactions. We also resolve the circumstellar disks around RW Aur A and B, with CO radii of 58 au and 38 au consistent with tidal truncation, and 2.5 times smaller dust emission radii. The disks appear misaligned by 12$^{\circ}$ or 57$^{\circ}$. Using new photometric observations from the American Association of Variable Star Observers (AAVSO) and All Sky Automated Survey for SuperNovae (ASAS-SN) archives, we have also identified an additional dimming event of the primary that began in late 2017 and is currently ongoing. With over a century of photometric observations, we are beginning to explore the same spatial scales as ALMA., 17 pages, 11 figures, 2 tables, Published in ApJ
Published: 2018
Full Text: View/download PDF

3. Seeds Of Life In Space (SOLIS): The Organic Composition Diversity at 300-1000 au Scale in Solar-type Star-forming Regions

Author: R. Choudhury, Emmanuel Caux, Felipe O. Alves, Jacob C. Laas, Albert Rimola, François Dulieu, Satoshi Yamamoto, Charlotte Vastel, Francesco Fontani, Serena Viti, Anton Vasyunin, Leonardo Testi, E. Bianchi, Jonathan Holdship, Ana Chacón-Tanarro, Nami Sakai, P. Hily-Blant, J. Ospina, Sandrine Bottinelli, Claudine Kahane, Andy Pon, D. Quénard, Bertrand Lefloch, Piero Ugliengo, Laurent Wiesenfeld, Ana López-Sepulcre, R. Neri, Rafael Bachiller, Cecilia Ceccarelli, Jaime E. Pineda, Claudio Codella, Vianney Taquet, Cécile Favre, Paola Caselli, Anna Punanova, A. Jaber Al-Edhari, Patrice Theulé, Linda Podio, S. Spezzano, Luca Bizzocchi, Yoko Oya, Audrey Coutens, Siyi Feng, Nadia Balucani, Ian R. Sims, Izaskun Jiménez-Serra, Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Max Planck Institute for Extraterrestrial Physics (MPE), Max-Planck-Gesellschaft, INAF - Osservatorio Astronomico di Brera (OAB), Istituto Nazionale di Astrofisica (INAF), INAF - Osservatorio Astrofisico di Arcetri (OAA), Queen Mary University of London (QMUL), University College of London [London] (UCL), Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Università degli Studi di Perugia (UNIPG), Università degli Studi di Firenze [Firenze], Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), University of Western Ontario (UWO), Universitat Autònoma de Barcelona [Barcelona] (UAB), RIKEN - Institute of Physical and Chemical Research [Japon] (RIKEN), Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Physique des interactions ioniques et moléculaires (PIIM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Università degli studi di Torino (UNITO), Ural Federal University [Ekaterinburg] (UrFU), Centre National de la Recherche Scientifique (CNRS), University of Electro-Communications [Tokyo] (UEC), European Research Council (ERC) [320620, 741002], French program Physique et Chimie du Milieu Interstellaire (PCMI) - Conseil National de la Recherche Scientifique (CNRS), Centre National dEtudes Spatiales (CNES), Italian Ministero dell'Istruzione, Universita e Ricerca, through the grant Progetti Premiali iALMA [CUP C52I13000140001], Canadian Institute for Theoretical Astrophysics (CITA) National Fellowship, STFC [ST/L004801, ST/M004139], Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Université 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), Università degli Studi di Perugia = University of Perugia (UNIPG), Università degli Studi di Firenze = University of Florence (UniFI), LERMA Cergy (LERMA), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris-Seine-Université Paris-Seine-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Universitat Autònoma de Barcelona (UAB), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), Università degli studi di Torino = University of Turin (UNITO), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France, Max-Planck-Institut fur Extraterrestrische Physik, Giessenbachstrasse 1, D-85748 Garching, Germany, INAF-Osservatorio Astrofisico di Arcetri (INAF-OAA), Institut de RadioAstronomie Millimétrique (IRAM), Department of Physics and Astronomy, University College London, Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), 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)-Université Fédérale Toulouse Midi-Pyrénées-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), Observatorio Astronómico Nacional, Observatorio de Madrid, Alfonso XII (OAN), 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), Molécules dans l'Univers, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères (LERMA (UMR_8112)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)-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)-CY Cergy Paris Université (CY), University of AL-Muthanna, College of Science, Physics Department, AL-Muthanna, Iraq, Department of Physics, University of Tokyo, Departament de Quimica, Universitat Autonoma de Barcelona, E-08193 Bellaterra, Spain, RIKEN The Institute of Physical and Chemical Research, Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Università degli Studi di Firenze = University of Florence [Firenze] (UNIFI), Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Cergy Pontoise (UCP), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)
Subjects: radio lines ISM, FOS: Physical sciences, Scale (descriptive set theory), Astrophysics, Type (model theory), Star (graph theory), Space (mathematics), ISM: clouds, 01 natural sciences, ISM: abundances, Spectral line, ISM molecules, Abundance (ecology), ISM: molecules, radio lines: ISM, Astronomy and Astrophysics, Space and Planetary Science, 0103 physical sciences, 14. Life underwater, 010303 astronomy & astrophysics, ISM abundances, Solar and Stellar Astrophysics (astro-ph.SR), ComputingMilieux_MISCELLANEOUS, Physics, [PHYS]Physics [physics], 010308 nuclear & particles physics, Astrophysics - Astrophysics of Galaxies, Interstellar medium, ISM clouds, Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Astrophysics of Galaxies (astro-ph.GA), Molecular physics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Order of magnitude
Abstract: Complex organic molecules have been observed for decades in the interstellar medium. Some of them might be considered as small bricks of the macromolecules at the base of terrestrial life. It is hence particularly important to understand organic chemistry in Solar-like star forming regions. In this article, we present a new observational project: SOLIS (Seeds Of Life In Space). This is a Large Project at the IRAM-NOEMA interferometer, and its scope is to image the emission of several crucial organic molecules in a sample of Solar-like star forming regions in different evolutionary stage and environments. Here, we report the first SOLIS results, obtained from analysing the spectra of different regions of the Class 0 source NGC1333-IRAS4A, the protocluster OMC-2 FIR4, and the shock site L1157-B1. The different regions were identified based on the images of formamide (NH2CHO) and cyanodiacetylene (HC5N) lines. We discuss the observed large diversity in the molecular and organic content, both on large (3000-10000 au) and relatively small (300-1000 au) scales. Finally, we derive upper limits to the methoxy fractional abundance in the three observed regions of the same order of magnitude of that measured in few cold prestellar objects, namely ~10^-12-10^-11 with respect to H2 molecules., Comment: Accepted for publication on The Astrophysical Journal
Published: 2017
Full Text: View/download PDF

4. The Next Generation Virgo Cluster Survey. XX. RedGOLD Background Galaxy Cluster Detections

Author: Roberto Munoz, Thomas H. Puzia, Marc Huertas-Company, Laura Ferrarese, Thomas Erben, Ariane Lançon, Stephen D. J. Gwyn, Ludovic Van Waerbeke, Carolina Parroni, Anand Raichoor, Hendrik Hildebrandt, Rossella Licitra, Simona Mei, Pierre-Alain Duc, Jean-Charles Cuillandre, Patrick Côté, 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), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Argelander-Institut für Astronomie (AlfA), Rheinische Friedrich-Wilhelms-Universität Bonn, Centro de Investigacion y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV), National Research Council of Canada (NRC), Canada-France-Hawaii Telescope Corporation (CFHT), National Research Council of Canada (NRC)-Centre National de la Recherche Scientifique (CNRS)-University of Hawai'i [Honolulu] (UH), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris), 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), Observatoire de Paris, Université Paris sciences et lettres (PSL), Observatoire astronomique de Strasbourg (ObAS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Pontificia Universidad Católica de Chile (UC), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS-PSL), and Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: [PHYS]Physics [physics], Physics, Cosmology and Nongalactic Astrophysics (astro-ph.CO), 010308 nuclear & particles physics, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics - Astrophysics of Galaxies, 01 natural sciences, Virgo Cluster, Galaxy, law.invention, Red shift, Telescope, Space and Planetary Science, law, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Cluster (physics), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, Galaxy cluster, Astrophysics - Cosmology and Nongalactic Astrophysics, Photometric redshift
Abstract: We build a background cluster candidate catalog from the Next Generation Virgo Cluster Survey, using our detection algorithm RedGOLD. The NGVS covers 104$deg^2$ of the Virgo cluster in the $u^*,g,r,i,z$-bandpasses to a depth of $ g \sim 25.7$~mag (5$\sigma$). Part of the survey was not covered or has shallow observations in the $r$--band. We build two cluster catalogs: one using all bandpasses, for the fields with deep $r$--band observations ($\sim 20 \ deg^2$), and the other using four bandpasses ($u^*,g,i,z$) for the entire NGVS area. Based on our previous CFHT-LS W1 studies, we estimate that both of our catalogs are $\sim100\%$($\sim70\%$) complete and $\sim80\%$ pure, at $z\le 0.6$($z\lesssim1$), for galaxy clusters with masses of $M\gtrsim10^{14}\ M_{\odot}$. We show that when using four bandpasses, though the photometric redshift accuracy is lower, RedGOLD detects massive galaxy clusters up to $z\sim 1$ with completeness and purity similar to the five-band case. This is achieved when taking into account the bias in the richness estimation, which is $\sim40\%$ lower at $0.5\le z 1.4 \times 10^{14} \rm M_{\odot}$ and $0.08, Comment: Licitra e al. 2016, ApJ, 829, 44 Our catalogs are planned to be available on ADS
Published: 2016
Full Text: View/download PDF

5. Gaps and Rings in an ALMA Survey of Disks in the Taurus Star-forming Region

Author: Feng Long, Gregory J. Herczeg, Daniel Harsono, Nathan Hendler, Yann Boehler, Sylvie Cabrit, Francois Menard, Colette Salyk, Enrico Ragusa, Ilaria Pascucci, Doug Johnstone, Paola Pinilla, Giuseppe Lodato, Carlo F. Manara, Gijs D. Mulders, Giovanni Dipierro, Yao Liu, Henning Avenhaus, Brunella Nisini, Andrea Banzatti, Marco Tazzari, William J. Fischer, Suzan Edwards, Elisabetta Rigliaco, Gerrit van de Plas, Michael Gully-Santiago, Kavli Institute for Astronomy and Astrophysics [Beijing] (KIAA-PKU), Peking University [Beijing], National Optical Astronomy Observatory (NOAO), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Tianjin University of Science and Technology (TUST), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Tazzari, Marco [0000-0003-3590-5814], Apollo - University of Cambridge Repository, Centre National d'Études Spatiales [Toulouse] (CNES)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université de Cergy Pontoise (UCP), and Université Paris-Seine-Université Paris-Seine-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Brightness, Stellar mass, FOS: Physical sciences, Flux, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Star (graph theory), circumstellar matter, 01 natural sciences, Planet, 0103 physical sciences, planets and satellites: formation, 010306 general physics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), ComputingMilieux_MISCELLANEOUS, Astrophysics::Galaxy Astrophysics, Earth and Planetary Astrophysics (astro-ph.EP), [PHYS]Physics [physics], Physics, High contrast, Turbulence, protoplanetary disks, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Substructure, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics - Earth and Planetary Astrophysics
Abstract: Rings are the most frequently revealed substructure in ALMA dust observations of protoplanetary disks, but their origin is still hotly debated. In this paper, we identify dust substructures in 12 disks and measure their properties to investigate how they form. This subsample of disks is selected from a high-resolution ($\sim0.12''$) ALMA 1.33 mm survey of 32 disks in the Taurus star-forming region, which was designed to cover a wide range of sub-mm brightness and to be unbiased to previously known substructures. While axisymmetric rings and gaps are common within our sample, spiral patterns and high contrast azimuthal asymmetries are not detected. Fits of disk models to the visibilities lead to estimates of the location and shape of gaps and rings, the flux in each disk component, and the size of the disk. The dust substructures occur across a wide range of stellar mass and disk brightness. Disks with multiple rings tend to be more massive and more extended. The correlation between gap locations and widths, the intensity contrast between rings and gaps, and the separations of rings and gaps could all be explained if most gaps are opened by low-mass planets (super-Earths and Neptunes) in the condition of low disk turbulence ($\alpha=10^{-4}$). The gap locations are not well correlated with the expected locations of CO and N$_2$ ice lines, so condensation fronts are unlikely to be a universal mechanism to create gaps and rings, though they may play a role in some cases., Comment: 23 pages, 11 figures, ApJ accepted
Published: 2018
Full Text: View/download PDF

6. Blue Compact Dwarf Galaxies withSpitzer: The Infrared/Radio Properties

Author: Bernhard R. Brandl, Jeronimo Bernard-Salas, Vianney Lebouteiller, Yanling Wu, James R. Houck, Duncan Farrah, Vassilis Charmandaris, School of Science, China University of Petroleum, Qingdao, China University of Petroleum, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris), 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), 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), Astronomy Centre, University of Sussex, École normale supérieure - Paris (ENS-PSL), 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), École normale supérieure - Paris (ENS Paris)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and PSL Research University (PSL)-PSL Research University (PSL)-Université de Cergy Pontoise (UCP)
Subjects: [PHYS.ASTR.HE]Physics [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE], [PHYS.ASTR.IM]Physics [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], Infrared, Metallicity, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, 01 natural sciences, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], 0103 physical sciences, Dispersion (optics), Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, Astrophysics::Galaxy Astrophysics, Dwarf galaxy, Physics, 010308 nuclear & particles physics, Astrophysics (astro-ph), Late type, Astronomy and Astrophysics, Galaxy, [PHYS.ASTR.GA]Physics [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA], Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics
Abstract: We study the correlation between the radio, mid-infrared and far-infrared properties for a sample of 28 blue compact dwarf (BCD) and low metallicity star-forming galaxies observed by Spitzer. We find that these sources extend the same far-infrared to radio correlation typical of star forming late type alaxies to lower luminosities. In BCDs, the 24um (or 22um) mid-infrared to radio correlation is similar to starburst galaxies, though there is somewhat larger dispersion in their q_24 parameter compared to their q_FIR. No strong correlations between the q parameter and galaxy metallicity or effective dust temperature have been detected, though there is a hint of decreasing q_24 at low metallicities. The two lowest metallicity dwarfs in our sample, IZw18 and SBS0335-052E, despite their similar chemical abundance, deviate from the average q$_{24}$ ratio in opposite manners, displaying an apparent radio excess and dust excess respectively., Comment: 8 pages, 4 figures, accepted by ApJ
Published: 2008
Full Text: View/download PDF

7. Deep GALEX Imaging of the COSMOS HST Field: A First Look at the Morphology of z ~ 0.7 Star-forming Galaxies

Author: Peter Capak, Susan G. Neff, B. Milliard, Ted K. Wyder, Sukyoung K. Yi, E. Bertin, D. B. Sanders, Alexander S. Szalay, Tom A. Barlow, J. Kartaltepe, Anton M. Koekemoer, Shunji S. Sasaki, M. Zamojski, B. F. Madore, David Thompson, Luciana Bianchi, T. Small, P. Morrisey, Yannick Mellier, Bahram Mobasher, O. Ilbert, H. J. McCracken, H. Aussel, Yoshiaki Taniguchi, Y. W. Lee, Barry Y. Welsh, Karl Forster, David Schiminovich, D. C. Martin, Mark Seibert, Peter G. Friedman, Mara Salvato, Jose Donas, R. M. Rich, Nick Scoville, O. Le Fevre, Timothy M. Heckman, Laboratoire de Physique Statistique de l'ENS (LPS), Université Paris Diderot - Paris 7 (UPD7)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Institut d'Astrophysique de Paris (IAP), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), 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), Laboratoire de Statistiques et Analyse des Données (LABSAD), Université Pierre Mendès France - Grenoble 2 (UPMF), Laboratoire d'Astrophysique de Marseille (LAM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES), California Institute of Technology (CALTECH), Center for Astrophysical Sciences [Baltimore], Johns Hopkins University (JHU), Department of Physics and Astronomy [Baltimore], Pohang University of Science and Technology (POSTECH), Center for Space Astrophysics [Seoul], Yonsei University, Observatories [Carnegie Institution], Carnegie Institution for Science [Washington], LAM Population Stellaire et Evolution des Galaxies, Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-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)-Centre National de la Recherche Scientifique (CNRS), 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), Carnegie Institution for Science, Beaussier, Catherine, Laboratoire de Physique Statistique de l'ENS ( LPS ), Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris ( FRDPENS ), École normale supérieure - Paris ( ENS Paris ) -Centre National de la Recherche Scientifique ( CNRS ) -École normale supérieure - Paris ( ENS Paris ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Université Paris Diderot - Paris 7 ( UPD7 ) -Centre National de la Recherche Scientifique ( CNRS ), Institut d'Astrophysique de Paris ( IAP ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique ( LERMA ), École normale supérieure - Paris ( ENS Paris ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Observatoire de Paris-Université de Cergy Pontoise ( UCP ), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique ( CNRS ), Laboratoire de Statistiques et Analyse des Données ( LABSAD ), Université Pierre Mendès France - Grenoble 2 ( UPMF ), Laboratoire d'Astrophysique de Marseille ( LAM ), Aix Marseille Université ( AMU ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National d'Etudes Spatiales ( CNES ) -Centre National de la Recherche Scientifique ( CNRS ), California Institute of Technology ( CALTECH ), Deptartment of Physics and Astronomy, Johns Hopkins University ( JHU ), Pohang University of Science and Technology ( POSTECH ), Meteorological Research Institute, and Korea Meteorological Administration
Subjects: Field (physics), [SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Population, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Star (graph theory), [ PHYS.ASTR.CO ] Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], [SDU.ASTR] Sciences of the Universe [physics]/Astrophysics [astro-ph], 01 natural sciences, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Bulge, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, education, 010303 astronomy & astrophysics, [ SDU.ASTR ] Sciences of the Universe [physics]/Astrophysics [astro-ph], Astrophysics::Galaxy Astrophysics, [SDU.ASTR.CO] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Physics, education.field_of_study, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010308 nuclear & particles physics, Star formation, Astrophysics (astro-ph), Astronomy and Astrophysics, Galaxy, Redshift, Bimodality, [ SDU.ASTR.CO ] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], [PHYS.ASTR.CO] Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Space and Planetary Science
Abstract: We present a study of the morphological nature of redshift z~0.7 star-forming galaxies using a combination of HST/ACS, GALEX and ground-based images of the COSMOS field. Our sample consists of 8,146 galaxies, 5,777 of which are detected in the GALEX near-ultraviolet band down to a limiting magnitude of 25.5 (AB). We make use of the UV to estimate star formation rates, correcting for the effect of dust using the UV-slope, and compute, from the ACS F814W images, the C,A,S,G,M20 morphological parameters for all objects in our sample. We observe a morphological bimodality in the galaxy population and show that it has a strong correspondence with the FUV - g color bimodality. We conclude that UV-optical color predominantly evolves concurrently with morphology. We observe many of the most star-forming galaxies to have morphologies approaching that of early-type galaxies, and interpret this as evidence that strong starburst events are linked to bulge growth and constitute a process through which galaxies can be brought from the blue to the red sequence while simultaneously modifying their morphology accordingly. We conclude that the red sequence has continued growing at z~, 29 pages including 22 figures. Accepted for publication in ApJS COSMOS Special Issue. A copy of the paper with high resolution figures is available at http://www.astro.columbia.edu/~michel/galex_cosmos_paper.pdf
Published: 2007

8. LOW-VELOCITY SHOCKS TRACED BY EXTENDED SiO EMISSION ALONG THE W43 RIDGES: WITNESSING THE FORMATION OF YOUNG MASSIVE CLUSTERS

Author: Friedrich Wyrowski, Nicola Schneider, Peter Schilke, Peter G. Martin, F. Louvet, Pierre Didelon, Karl M. Menten, C. Kramer, Frédérique Motte, Ana Duarte-Cabral, Th. Henning, Fabian Heitsch, Sylvain Bontemps, P. Carlhoff, M. Hennemann, George J. Bendo, Leonardo Bronfman, Tracey Hill, Pierre Lesaffre, Q. Nguy˜ên-Lu’o’ng, H. Roussel, Antoine Gusdorf, J.-P. Bernard, Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Groupe d'Etudes des Matériaux Hétérogènes (GEMH), Université de Limoges (UNILIM)-Institut des Procédés Appliqués aux Matériaux (IPAM), Université de Limoges (UNILIM)-Université de Limoges (UNILIM), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Max Planck Institute for Radio Astronomy, Univ Cologne, Inst Phys 1, D-50937 Cologne, Germany, Univ Cologne, Inst Phys 1, 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), FORMATION STELLAIRE 2013, Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB), Max-Planck-Institut für Radioastronomie (MPIFR), Centre d'étude spatiale des rayonnements (CESR), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Departamento de Astronomia (DAS), Universidad de Santiago de Chile [Santiago] (USACH), Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Gesellschaft, Instituto de RadioAstronomía Milimétrica (IRAM), Centre National de la Recherche Scientifique (CNRS), 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), I. Physikalisches Institut [Köln], Universität zu Köln = University of Cologne, 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 Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), 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), École normale supérieure - Paris (ENS Paris), Universität zu Köln, Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), and Université Fédérale Toulouse Midi-Pyrénées
Subjects: Gravity (chemistry), Cosmology and Nongalactic Astrophysics (astro-ph.CO), ISM: structure, Continuum (design consultancy), FOS: Physical sciences, Astrophysics, ISM: clouds, 01 natural sciences, Luminosity, H II regions, 0103 physical sciences, 010303 astronomy & astrophysics, QB, Physics, stars: formation, stars: protostars, Shock (fluid dynamics), [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], 010308 nuclear & particles physics, Star formation, Molecular cloud, Velocity dispersion, Astronomy and Astrophysics, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Astrophysics - Astrophysics of Galaxies, ISM: molecules, Stars, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract: The formation of high-mass stars is tightly linked to that of their parental clouds. We here focus on the high-density parts of W43, a molecular cloud undergoing an efficient event of formation. The cloud structure is studied with a column density image derived from Herschel continuum maps obtained at 70, 160, 250, 350, and 500 micron. We identify two high-column density filamentary clouds, quoted as the W43-MM1 and W43-MM2 ridges, which both account for 1.5x10^4 Msun gas mass above 10^23 cm-2 and within areas of 5 and 14pc^2, respectively. We used the N_2H^+ 1--0 line to confirm that the W43-MM1 and W43-MM2 ridges are structures coherent in velocity and gravitationally bound, despite their large velocity dispersion and ~5 kms line widths. The most intriguing result of the W43 large program is the bright wide-spread SiO 2--1 emission: 1--11 K kms$ stretching an area of ~28 pc^2. Concentrated toward the W43-MM1 and W43-MM2 ridges and their immediate surroundings, it leads to a total luminosity of L_SiO 2-1 ~4 10^4 K kms kpc^2pc^2. We measured a steep relation between the luminosity and velocity extent of the SiO~2--1 lines and propose to use it to distinguish the low-velocity shocks observed here from the more classical high-velocity ones associated with outflows of high-mass young stellar objects. We used state-of-the-art shock models to demonstrate that low-velocity (10^4-10^5 cm^-3) and the shocked SiO gas suggests that ridges could be forming via colliding flows driven by gravity and accompanied by low-velocity shocks. This mechanism may be the initial conditions for the formation of young massive clusters in these ridges., accepted for publication to ApJ in July 2013
Published: 2013
Full Text: View/download PDF

9. MAGNETIZED ACCRETION AND DEAD ZONES IN PROTOSTELLAR DISKS

Author: Neal J. Turner, Thomas Henning, Natalia Dzyurkevich, Wilhelm Kley, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris), 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), Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Gesellschaft, École normale supérieure - Paris (ENS Paris)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université de Cergy Pontoise (UCP), and École normale supérieure - Paris (ENS-PSL)
Subjects: Planetesimal, 010504 meteorology & atmospheric sciences, FOS: Physical sciences, Astrophysics, Dead zone, Electron, Trapping, 01 natural sciences, Planet, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), ComputingMilieux_MISCELLANEOUS, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), [PHYS]Physics [physics], Physics, Ambipolar diffusion, Turbulence, Astronomy and Astrophysics, Accretion (astrophysics), 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 edges of magnetically-dead zones in protostellar disks have been proposed as locations where density bumps may arise, trapping planetesimals and helping form planets. Magneto-rotational turbulence in magnetically-active zones provides both accretion of gas on the star and transport of mass to the dead zone. We investigate the location of the magnetically-active regions in a protostellar disk around a solar-type star, varying the disk temperature, surface density profile, and dust-to-gas ratio. We also consider stellar masses between 0.4 and 2 $M_\odot$, with corresponding adjustments in the disk mass and temperature. The dead zone's size and shape are found using the Elsasser number criterion with conductivities including the contributions from ions, electrons, and charged fractal dust aggregates. The charged species' abundances are found using the approach proposed by S. Okuzumi. The dead zone is in most cases defined by the ambipolar diffusion. In our maps, the dead zone takes a variety of shapes, including a fish-tail pointing away from the star and islands located on and off the midplane. The corresponding accretion rates vary with radius, indicating locations where the surface density will increase over time, and others where it will decrease. We show that density bumps do not readily grow near the dead zone's outer edge, independently of the disk parameters and the dust properties. Instead, the accretion rate peaks at the radius where the gas-phase metals freeze out. This could lead to clearing a valley in the surface density, and to a trap for pebbles located just outside the metal freeze-out line., Comment: 58 pages, 25 figures, 2 tables, accepted to ApJ
Published: 2013
Full Text: View/download PDF

10. EXPERIMENTAL INVESTIGATION OF THE ORTHO/PARA RATIO OF NEWLY FORMED MOLECULAR HYDROGEN ON AMORPHOUS SOLID WATER

Author: Jean-Louis Lemaire, Lisseth Gavilan, J. H. Fillion, H. Chaabouni, François Dulieu, M. Chehrouri, E. Congiu, Gianfranco Vidali, 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), Belgian Institute for Space Aeronomy / Institut d'Aéronomie Spatiale de Belgique (BIRA-IASB), LERMA Cergy (LERMA), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris-Seine-Université Paris-Seine-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Moleculaire pour l'Atmosphere et l'Astrophysique (LPMAA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS Paris), Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Cergy Pontoise (UCP), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)
Subjects: [PHYS]Physics [physics], Physics, Astrochemistry, 010304 chemical physics, Hydrogen, Thermodynamic equilibrium, Extinction (astronomy), Analytical chemistry, chemistry.chemical_element, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Amorphous solid, Interstellar medium, chemistry, 13. Climate action, Space and Planetary Science, 0103 physical sciences, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Porous medium, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, Cosmic dust
Abstract: Several astronomical observations have shown that the ortho/para ratio (OPR) of H2 can differ from the expected statistical value of 3 or the local thermodynamic equilibrium (LTE) value at the gas or dust temperature. It is thus important to know the OPR of H2 newly formed on dust grain surfaces, in order to clarify the dependence of the observed OPR in space on the formation process. Using an experimental setup designed to mimic interstellar medium environments, we measured the OPR of H2 and D2 formed on the surface of porous amorphous water ice held at 10 K. We report for the first time the OPR value for newly formed D2, consistent with the expected LTE value at the high-temperature limit found by previous theoretical and experimental works on the determination of the OPR upon H2 formation on surfaces at low temperature.
Published: 2012
Full Text: View/download PDF

11. EXPERIMENTAL EVIDENCE FOR THE FORMATION OF HIGHLY SUPERHYDROGENATED POLYCYCLIC AROMATIC HYDROCARBONS THROUGH H ATOM ADDITION AND THEIR CATALYTIC ROLE IN H2FORMATION

Author: Alan C. Luntz, Liv Hornekær, Mie Andersen, Bjarke Jørgensen, J. D. Thrower, S. Baouche, Emil E. Friis, Vito Mennella, Bjørk Hammer, Westfälische Wilhelms-Universität Münster (WWU), Biomécanique et génie biomédical (BIM), Centre National de la Recherche Scientifique (CNRS), LERMA Cergy (LERMA), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Cergy Pontoise (UCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Paul Scherrer Institute (PSI), Department of Physics and Astronomy [Aarhus], and Aarhus University [Aarhus]
Subjects: Astrochemistry, Hydrogen, Polycyclic aromatic hydrocarbon, chemistry.chemical_element, 010402 general chemistry, Photochemistry, Mass spectrometry, 01 natural sciences, Catalysis, Cosmochemistry, chemistry.chemical_compound, 0103 physical sciences, 11. Sustainability, Molecule, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, [PHYS]Physics [physics], chemistry.chemical_classification, Physics, Astronomy and Astrophysics, Coronene, 0104 chemical sciences, chemistry, Space and Planetary Science, Atomic physics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: Mass spectrometry measurements show the formation of highly superhydrogenated derivatives of the polycyclic aromatic hydrocarbon molecule coronene through H atom addition reactions. The observed product mass distribution provides evidence also for abstraction reactions resulting in H2 formation, in agreement with recent IR measurements. Complementary density functional theory calculations confirm the stability of the observed superhydrogenated species toward spontaneous H and H2 loss indicating that abstraction reactions may be the dominant route to H2 formation involving neutral polycyclic aromatic hydrocarbons (PAHs). The results indicate that highly superhydrogenated PAHs could well be formed and could act as efficient catalysts for H2 formation in the interstellar medium in low UV flux regions.
Published: 2012
Full Text: View/download PDF

12. INFLUENCE OF THE ENVIRONMENT ON POLYCYCLIC AROMATIC HYDROCARBON EMISSION IN STAR-FORMING REGIONS

Author: D. Kunth, Jeronimo Bernard-Salas, Frédéric Galliano, Suzanne C. Madden, David G. Whelan, Vassilis Charmandaris, Bernhard R. Brandl, Vianney Lebouteiller, Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), 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), 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), Institut d'Astrophysique de Paris (IAP), Université Pierre et Marie Curie - Paris 6 (UPMC)-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)), 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), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS Paris), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), École normale supérieure - Paris (ENS Paris)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and PSL Research University (PSL)-PSL Research University (PSL)-Université de Cergy Pontoise (UCP)
Subjects: [PHYS.ASTR.HE]Physics [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE], [PHYS.ASTR.IM]Physics [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], Milky Way, Extinction (astronomy), Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, 01 natural sciences, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Large Magellanic Cloud, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, Astrophysics::Galaxy Astrophysics, Dwarf galaxy, Physics, Luminous infrared galaxy, 010308 nuclear & particles physics, Astronomy and Astrophysics, Galaxy, Interstellar medium, [PHYS.ASTR.GA]Physics [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA], 13. Climate action, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, Small Magellanic Cloud
Abstract: We investigate the emission properties of polycyclic aromatic hydrocarbons (PAHs) in various metallicity environments with the Infrared Spectrograph on board Spitzer. Local giant H II regions are used as references as they enable access to the distinct interstellar medium components that contribute to the mid-infrared spectrum of star-forming galaxies: photodissociation regions (PDRs), photoionized gas, stellar clusters, and embedded regions. Three objects are considered: NGC 3603 in the Milky Way, 30 Doradus in the Large Magellanic Cloud, and N 66 in the Small Magellanic Cloud. From the variations of the PAH/14 μm ratio, we find that PAHs are destroyed in the ionized gas for a radiation field such that [Ne iii]/[Ne ii] >~ 3. From the variations of the PAH/Huα ratio, we find that the PAH emission sources in the giant H II regions follow the same photodestruction law regardless of metallicity. We then compare these results with observations of starburst galaxies, Hii galaxies, and blue compact dwarf galaxies (BCDs). While the integrated mid-infrared spectra of BCDs are reminiscent of a warm dusty ionized gas, we observe a significant contribution to the PAH emission in starburst galaxies that is not arising from PDRs.
Published: 2011
Full Text: View/download PDF

13. HST Grism Confirmation of 16 Structures at 1.4 < z < 2.8 from the Clusters Around Radio-Loud AGN (CARLA) Survey

Author: Alessandro Rettura, Matt J. Jarvis, Daniel Stern, Audrey Galametz, Simona Mei, Anthony H. Gonzalez, Nick Seymour, Nina A. Hatch, Spencer A. Stanford, E. A. Cooke, Mark Brodwin, Gaël Noirot, Peter R. Eisenhardt, Carlos De Breuck, Dominika Wylezalek, Joel Vernet, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), European Southern Observatory (ESO), Institut d'Astrophysique de Paris (IAP), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Department of Astronomy [Pasadena], and California Institute of Technology (CALTECH)
Subjects: Physics, [PHYS]Physics [physics], 010308 nuclear & particles physics, Astrophysics::High Energy Astrophysical Phenomena, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics - Astrophysics of Galaxies, 01 natural sciences, Grism, Space and Planetary Science, Hubble space telescope, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Spectroscopy, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, Galaxy cluster, ComputingMilieux_MISCELLANEOUS, Astrophysics::Galaxy Astrophysics
Abstract: We report spectroscopic results from our 40-orbit $Hubble~Space~Telescope$ slitless grism spectroscopy program observing the 20 densest CARLA candidate galaxy clusters at $1.4 < z < 2.8$. These candidate rich structures, among the richest and most distant known, were identified on the basis of $[3.6]-[4.5]$ color from a $408~$hr multi-cycle $Spitzer$ program targeting $420$ distant radio-loud AGN. We report the spectroscopic confirmation of $16$ distant structures at $1.4 < z < 2.8$ associated with the targeted powerful high-redshift radio-loud AGN. We also report the serendipitous discovery and spectroscopic confirmation of seven additional structures at $0.87 < z < 2.12$ not associated with the targeted radio-loud AGN. We find that $10^{10} - 10^{11}\,M_{\odot}$ member galaxies of our confirmed CARLA structures form significantly fewer stars than their field counterparts at all redshifts within $1.4\leq z\leq 2$. We also observe higher star-forming activity in the structure cores up to $z = 2$, finding similar trends as cluster surveys at slightly lower redshifts ($1.0 < z < 1.5$). By design, our efficient strategy of obtaining just two grism orbits per field only obtains spectroscopic confirmation of emission-line galaxies. Deeper spectroscopy will be required to study the population of evolved, massive galaxies in these (forming) clusters. Lacking multi-band coverage of the fields, we adopt a very conservative approach of calling all confirmations "structures", although we note that a number of features are consistent with some of them being bona fide galaxy clusters. Together, this survey represents a unique and large homogenous sample of spectroscopically confirmed structures at high redshifts, potentially more than doubling the census of confirmed, massive clusters at $z > 1.4$., Comment: Accepted for publication in the Astrophysical Journal
Published: 2018
Full Text: View/download PDF

14. SHARDS Frontier Fields: Physical Properties of a Low-mass Lyα Emitter at z=5.75

Author: Helmut Dannerbauer, Helena Domínguez-Sánchez, Pablo G. Pérez-González, Daniel Rosa González, Jose M. Diego, Daniel Schaerer, Jose Miguel Rodriguez Espinosa, P. Esquej, David J. Lagattuta, Ismael Perez-Fournon, Belén Alcalde-Pampliega, Panos Sklias, Marc Huertas-Company, T. D. Rawle, Rui Marques-Chaves, Almudena Alonso-Herrero, Johan Richard, Carmen Eliche-Moral, Antonio Hernán-Caballero, Christopher J. Conselice, Raffaella Anna Marino, Antonio Cava, Wiphu Rujopakarn, Centre de Recherche Astrophysique de Lyon (CRAL), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Laboratoire d'Astrophysique de l'Observatoire Midi-Pyrénées (LATT), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Institut für Astronomie [Wien], Universität Wien, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris), 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), Observatoire de Paris, Université Paris sciences et lettres (PSL), Swiss National Science Foundation, European Research Council, European Commission, Ministerio de Economía y Competitividad (España), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), 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), and École normale supérieure - Paris (ENS-PSL)
Subjects: Astrofísica, Stellar population, Gravitational lensing: strong, Population, Early universe, FOS: Physical sciences, Astrophysics, strong [Gravitational lensing], 01 natural sciences, high-redshift [Galaxies], Dark ages, reionization, first stars, 0103 physical sciences, education, 010303 astronomy & astrophysics, Reionization, ComputingMilieux_MISCELLANEOUS, Physics, [PHYS]Physics [physics], education.field_of_study, Spectral index, 010308 nuclear & particles physics, Star formation, Galaxies: high-redshift, Galaxies: evolution, Astronomy and Astrophysics, evolution [Galaxies], Astrophysics - Astrophysics of Galaxies, Galaxy, Astronomía, starburst [Galaxies], 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Spectral energy distribution, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Equivalent width, Galaxies: starburst
Abstract: arXiv:1710.00826v1, We analyze the properties of a multiply imaged Lyα (Lyα) emitter at z = 5.75 identified through SHARDS Frontier Fields intermediate-band imaging of the Hubble Frontier Fields (HFF) cluster Abell 370. The source, A370-L57, has low intrinsic luminosity (M ∼ -16.5), steep UV spectral index (β = -2.4 ± 0.1), and extreme rest-frame equivalent width of Lyα. Two different gravitational lens models predict high magnification (μ ∼ 10-16) for the two detected counterimages, separated by 7″, while a predicted third counterimage (μ ∼ 3-4) is undetected. We find differences of ∼50% in magnification between the two lens models, quantifying our current systematic uncertainties. Integral field spectroscopy of A370-L57 with MUSE shows a narrow (FWHM = 204 ± 10 km s) and asymmetric Lyα profile with an integrated luminosity L(Lyα) ∼ 10 erg s. The morphology in the Hubble Space Telescope bands comprises a compact clump (r < 100 pc) that dominates the Lyα and continuum emission and several fainter clumps at projected distances ≲1 kpc that coincide with an extension of the Lyα emission in the SHARDS F823W17 and MUSE observations. The latter could be part of the same galaxy or an interacting companion. We find no evidence of a contribution from active galactic nuclei to the Lyα emission. Fitting of the spectral energy distribution with stellar population models favors a very young (t < 10 Myr), low-mass (), and metal-poor (Z ≲ 4 10) stellar population. Its modest star formation rate (SFR ∼ 1.0 yr) implies high specific SFR (sSFR ∼ 2.5 10 yr) and SFR density ( yr kpc). The properties of A370-L57 make it a good representative of the population of galaxies responsible for cosmic reionization., A.H.-C. and P.G.P.-G. acknowledge funding by the Spanish Ministry of Economy and Competitiveness (MINECO) under grants AYA2012-31277, AYA2015-70815-ERC, and AYA2015-63650-P. J.M.D. acknowledges support of the projects AYA2015-64508-P (MINECO/FEDER, UE), AYA2012-39475-C02-01, and the consolider project CSD2010-00064 funded by MINECO. D.J.L. and J.R. acknowledge support from the ERC starting grant 336736-CALENDS. R.A.M. acknowledges support by the Swiss National Science Foundation. A.A.-H. acknowledges funding by the MINECO grant AYA2015-64346-C2-1-P, which is partly funded by the FEDER program. H.D.S. acknowledges funding from the program ANR-T-ERC ASTROBRAIN. P.S. acknowledges funding from the Swiss National Science Foundation under grant P2GEP2_165426. J.M.R.E. acknowledges funding by the MINECO grant AYA2015-70498-C2-1-R. H.D. acknowledges financial support from the Spanish 2014 Ramón y Cajal program MINECO RYC-2014-15686.
Published: 2017
Full Text: View/download PDF

15. Mapping Metallicity Variations across Nearby Galaxy Disks

Author: Christopher Faesi, Francesco Santoro, Philipp Lang, Rebecca McElroy, Karin Sandstrom, Kathryn Grasha, Mélanie Chevance, Frank Bigiel, Guillermo A. Blanc, I-Ting Ho, Simon C. O. Glover, Toshiki Saito, Sharon Meidt, Jérôme Pety, Andreas Schruba, Eric Emsellem, Adam K. Leroy, Eva Schinnerer, J. M. D. Kruijssen, Brent Groves, Enrico Congiu, Kathryn Kreckel, Patricia Sanchez-Blazquez, Erik Rosolowsky, Centre de Recherche Astrophysique de Lyon (CRAL), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), 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: 010504 meteorology & atmospheric sciences, Metallicity, Chemical abundances, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, 01 natural sciences, Luminosity, Galaxy abundances, H II regions, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Disk galaxies, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, Spiral galaxies, Spiral galaxy, Star formation, Velocity dispersion, Astronomy and Astrophysics, Radius, Astrophysics - Astrophysics of Galaxies, Galaxy, Star cluster, Physics and Astronomy, [SDU]Sciences of the Universe [physics], Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA)
Abstract: The distribution of metals within a galaxy traces the baryon cycle and the buildup of galactic disks, but the detailed gas phase metallicity distribution remains poorly sampled. We have determined the gas phase oxygen abundances for 7,138 HII regions across the disks of eight nearby galaxies using VLT/MUSE optical integral field spectroscopy as part of the PHANGS-MUSE survey. After removing the first order radial gradients present in each galaxy, we look at the statistics of the metallicity offset (Delta O/H) and explore azimuthal variations. Across each galaxy, we find low (sigma=0.03-0.05 dex) scatter at any given radius, indicative of efficient mixing. We compare physical parameters for those HII regions that are 1 sigma outliers towards both enhanced and reduced abundances. Regions with enhanced abundances have high ionization parameter, higher Halpha luminosity, lower Halpha velocity dispersion, younger star clusters and associated molecular gas clouds show higher molecular gas densities. This indicates recent star formation has locally enriched the material. Regions with reduced abundances show increased Halpha velocity dispersions, suggestive of mixing introducing more pristine material. We observe subtle azimuthal variations in half of the sample, but can not always cleanly associate this with the spiral pattern. Regions with enhanced and reduced abundances are found distributed throughout the disk, and in half of our galaxies we can identify subsections of spiral arms with clearly associated metallicity gradients. This suggests spiral arms play a role in organizing and mixing the ISM., 14 pages, 9 figures, 4 Appendices including image atlases, ApJ accepted
Published: 2019
Full Text: View/download PDF

16. Erratum: 'Virgo Redux: The Masses and Stellar Content of Nuclei in Early-type Galaxies from Multiband Photometry and Spectroscopy' (2017, ApJ, 849, 55)

Author: Eric W. Peng, Rubén Sánchez-Janssen, Patrick Côté, Puragra Guhathakurta, Chelsea Spengler, Laura Ferrarese, E. Toloba, Andrew Zirm, Ariane Lançon, Mathieu Powalka, Roberto Munoz, Yiqing Liu, Jean-Charles Cuillandre, Joel Roediger, Simona Mei, Stephen Gwyn, Thomas H. Puzia, National Research Council of Canada (NRC), Texas Tech University [Lubbock] (TTU), UCO/Lick Observatory, University of California [Santa Cruz] (UCSC), University of California-University of California, Canada-France-Hawaii Telescope Corporation (CFHT), National Research Council of Canada (NRC)-Centre National de la Recherche Scientifique (CNRS)-University of Hawai'i [Honolulu] (UH), Centro de Investigacion y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV), Pontificia Universidad Católica de Chile (UC), Observatoire astronomique de Strasbourg (ObAS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)
Subjects: [PHYS]Physics [physics], Physics, 010504 meteorology & atmospheric sciences, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Galaxy, Early type, Photometry (astronomy), Space and Planetary Science, 0103 physical sciences, Content (measure theory), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Spectroscopy, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract: International audience
Published: 2018
Full Text: View/download PDF

17. THE THERMALLY UNSTABLE WARM NEUTRAL MEDIUM: KEY FOR MODELING THE INTERSTELLAR MEDIUM

Author: Anthony S. Pavkovich, Carl Heiles, Ayesha Begum, Patrick Hennebelle, Snezana Stanimirovic, W. M. Goss, University of Wisconsin-Madison, National Radio Astronomy Observatory, Socorro (NRAO), Radio Astronomy Laboratory, University of California, Berkeley, 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: Very large array, Physics, Absorption spectroscopy, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics - Astrophysics of Galaxies, Interstellar medium, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Thermal, Arecibo Observatory, Emission spectrum, Detection rate, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: We present 21-cm absorption measurements towards 12 radio continuum sources with previously identified thermally-unstable warm neutral medium (WNM). These observations were obtained with the Expanded Very Large Array (EVLA) and were complemented with the HI emission spectra obtained with the Arecibo Observatory. Out of 12 sources, HI absorption was detected along 5 lines of sight (seven new absorption features in total), resulting in a detection rate of ~42%. While our observations are sensitive to the WNM with a spin temperature T_s, 10 pages. Accepted by ApJ
Published: 2010
Full Text: View/download PDF

18. A COMPREHENSIVE SURVEY OF HYDROGEN CHLORIDE IN THE GALAXY

Author: Thomas G. Phillips, Hiroshige Yoshida, M. Gerin, Richard Chamberlin, Ruisheng Peng, Dariusz C. Lis, Caltech Submillimeter Observatory, Division of Physics, Mathematics and Astronomy, California Institute of Technology, 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), Dynamique des milieux interstellaires et plasmas stellaires, 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), and Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)
Subjects: Metallicity, FOS: Physical sciences, Astrophysics, 7. Clean energy, 01 natural sciences, chemistry.chemical_compound, Nucleosynthesis, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, Physics::Chemical Physics, 010306 general physics, Hydrogen chloride, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Physics, Molecular cloud, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Galaxy, Supernova, Stars, Caltech Submillimeter Observatory, chemistry, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: We report new observations of the fundamental $J=1-0$ transition of HCl (at 625.918GHz) toward a sample of 25 galactic star-forming regions, molecular clouds, and evolved stars, carried out using the Caltech Submillimeter Observatory. Fourteen sources in the sample are also observed in the corresponding H\tscl\ $J=1-0$ transition (at 624.978GHz). We have obtained clear detections in all but four of the targets, often in emission. Absorptions against bright background continuum sources are also seen in nine cases, usually involving a delicate balance between emission and absorption features. From RADEX modeling, we derive gas densities and HCl column densities for sources with HCl emission. HCl is found in a wide range of environments, with gas densities ranging from $10^5$ to $10^7$~cm$^{-3}$. The HCl abundance relative to H$_2$ is in the range of $(3-30)\times10^{-10}$. Comparing with the chlorine abundance in the solar neighborhood, this corresponds to a chlorine depletion factor of up to $\sim$400, assuming that HCl accounts for one third of the total chlorine in the gas phase. The [\tfcl]/[\tscl] isotopic ratio is rather varied, from unity to $\sim$5, mostly lower than the terrestrial value of 3.1. Such variation is highly localized, and could be generated by the nucleosynthesis in supernovae, which predicts a \tscl\ deficiency in most models. The lower ratios seen in W3IRS4 and W3IRS5 likely confine the progenitors of the supernovae to stars with relatively large mass ($\ga$25M$_\sun$) and high metallicity (Z$\sim$0.02)., 11 pages, 5 figures, accepted by ApJ
Published: 2010
Full Text: View/download PDF

19. SPITZERVIEW OF YOUNG MASSIVE STARS IN THE LARGE MAGELLANIC CLOUD H II COMPLEXES. II. N 159

Author: Fabian Heitsch, Jonathan Seale, Gerard Testor, Marta Sewilo, C.-H. Rosie Chen, Remy Indebetouw, Robert A. Gruendl, You-Hua Chu, Margaret Meixner, Astronomy Department, University of Virginia, Charlottesville, Department of Astronomy, University of Illinois, Observatoire de Paris, Université Paris sciences et lettres (PSL), 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), Department of Physics and Astronomy, University of North Carolina, and Space Telescope Science Institute (STScI)
Subjects: Physics, Infrared, Star formation, Molecular cloud, Young stellar object, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, law.invention, Photometry (astronomy), Stars, Space and Planetary Science, law, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Maser, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Large Magellanic Cloud, Astrophysics::Galaxy Astrophysics
Abstract: International audience; The H II complex N 159 in the Large Magellanic Cloud is used to study massive star formation in different environments, as it contains three giant molecular clouds (GMCs) that have similar sizes and masses but exhibit different intensities of star formation. We identify candidate massive young stellar objects (YSOs) using infrared photometry, and model their spectral energy distributions to constrain mass and evolutionary state. Good fits are obtained for less evolved Type I, I/II, and II sources. Our analysis suggests that there are massive embedded YSOs in N 159B, a maser source, and several ultracompact H II regions. Massive O-type YSOs are found in GMCs N 159-E and N 159-W, which are associated with ionized gas, i.e., where massive stars formed a few Myr ago. The third GMC, N 159-S, has neither O-type YSOs nor evidence of previous massive star formation. This correlation between current and antecedent formation of massive stars suggests that energy feedback is relevant. We present evidence that N 159-W is forming YSOs spontaneously, while collapse in N 159-E may be triggered. Finally, we compare star formation rates determined from YSO counts with those from integrated Halpha and 24 mum luminosities and expected from gas surface densities. Detailed dissection of extragalactic GMCs like the one presented here is key to revealing the physics underlying commonly used star formation scaling laws.
Published: 2010
Full Text: View/download PDF

20. Molecular Gas Filaments and Star-forming Knots Beneath an X-Ray Cavity in RXC J1504–0248

Author: Alastair C. Edge, Brian R. McNamara, Andrew C. Fabian, P. Salomé, Michael McDonald, Paul Nulsen, Helen Russell, A. N. Vantyghem, Francoise Combes, Institute for Computational Cosmology (ICC), Durham University, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Chaire Galaxies et cosmologie, Collège de France (CdF (institution)), Institute of Astronomy [Cambridge], and University of Cambridge [UK] (CAM)
Subjects: [PHYS]Physics [physics], Physics, Active galactic nucleus, 010308 nuclear & particles physics, Star formation, Galactic Center, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Astrophysics - Astrophysics of Galaxies, 01 natural sciences, Galaxy, Protein filament, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Cluster (physics), Emission spectrum, Brightest cluster galaxy, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, Astrophysics::Galaxy Astrophysics
Abstract: We present recent ALMA observations of the CO(1-0) and CO(3-2) emission lines in the brightest cluster galaxy of RXCJ1504.1$-$0248, which is one of the most extreme cool core clusters known. The central galaxy contains $1.9\times 10^{10}~M_{\odot}$ of molecular gas. The molecular gas morphology is complex and disturbed, showing no evidence for a rotationally-supported structure in equilibrium. $80\%$ of the gas is situated within the central 5 kpc of the galactic center, while the remaining gas is located in a 20 kpc long filament. The cold gas has likely condensed out of the hot atmosphere. The filament is oriented along the edge of a putative X-ray cavity, suggesting that AGN activity has stimulated condensation. This is enegetically feasible, although the morphology is not as conclusive as systems whose molecular filaments trail directly behind buoyant radio bubbles. The velocity gradient along the filament is smooth and shallow. It is only consistent with free-fall if it lies within $20^{\circ}$ of the plane of the sky. The abundance of clusters with comparably low velocities suggests that the filament is not free-falling. Both the central and filamentary gas are coincident with bright UV emission from ongoing star formation. Star formation near the cluster core is consistent with the Kennicutt-Schmidt law. The filament exhibits increased star formation surface densities, possibly resulting from either the consumption of a finite molecular gas supply or spatial variations in the CO-to-H$_2$ conversion factor., 15 pages, 10 figures, accepted in ApJ
Published: 2018
Full Text: View/download PDF

21. THESPITZER-IRAC POINT-SOURCE CATALOG OF THE VELA-D CLOUD

Author: Massimo Marengo, M. De Luca, T. Giannini, Fabrizio Massi, Francesco Strafella, D. Lorenzetti, Howard A. Smith, Davide Elia, Giovanni G. Fazio, L. Campeggio, Dipartimento di Fisica, Universitá del Salento, INAF-Osservatorio Astronomico di Roma (INAF-OAR), Department of Physics and Astronomy, Iowa State University, Harvard-Smithsonian Center for Astrophysics, 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), and INAF-Osservatorio Astrofisico di Arcetri (INAF-OAA)
Subjects: Physics, education.field_of_study, Stellar population, Point source, Star formation, Young stellar object, Population, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Vela, Astrophysics - Astrophysics of Galaxies, Photometry (optics), Spitzer Space Telescope, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], education, Astrophysics::Galaxy Astrophysics
Abstract: This paper presents the observations of the Cloud D in the Vela Molecular Ridge, obtained with the IRAC camera onboard the Spitzer Space Telescope at the wavelengths \lambda = 3.6, 4.5, 5.8, 8.0 {\mu}m. A photometric catalog of point sources, covering a field of approximately 1.2 square degrees, has been extracted and complemented with additional available observational data in the millimeter region. Previous observations of the same region, obtained with the Spitzer MIPS camera in the photometric bands at 24 {\mu}m and 70 {\mu}m, have also been reconsidered to allow an estimate of the spectral slope of the sources in a wider spectral range. A total of 170,299 point sources, detected at the 5-sigma sensitivity level in at least one of the IRAC bands, have been reported in the catalog. There were 8796 sources for which good quality photometry was obtained in all four IRAC bands. For this sample, a preliminary characterization of the young stellar population based on the determination of spectral slope is discussed; combining this with diagnostics in the color-magnitude and color-color diagrams, the relative population of young stellar objects in the different evolutionary classes has been estimated and a total of 637 candidate YSOs have been selected. The main differences in their relative abundances have been highlighted and a brief account for their spatial distribution is given. The star formation rate has been also estimated and compared with the values derived for other star forming regions. Finally, an analysis of the spatial distribution of the sources by means of the two-point correlation function shows that the younger population, constituted by the Class I and flat-spectrum sources, is significantly more clustered than the Class II and III sources., Comment: Accepted by ApJ
Published: 2010
Full Text: View/download PDF

22. THE GREAT OBSERVATORIES ALL-SKY LIRG SURVEY: COMPARISON OF ULTRAVIOLET AND FAR-INFRARED PROPERTIES

Author: Hanae Inami, Phil Appleton, Ben Chan, Jason Surace, Greg Bothun, Lee Armus, Joseph M. Mazzarella, T. Vavilkin, Jason Melbourne, Sylvain Veilleux, Justin Howell, Andreea Petric, Vivian U, David T. Frayer, Kevin Xu, Bernhard Schulz, Barry F. Madore, D. C. Kim, David B. Sanders, Aaron S. Evans, S. Haan, Carrie Bridge, Steven D. Lord, Vassilis Charmandaris, Spitzer Science Center, California Institute of Technology (SSC), Infrared Processing Analysis Center, California Institute of Technology (IPAC), Astronomy Department, University of Virginia, Charlottesville, Institute for Astronomy, University of Hawaii, Department of Physics, University of Oregon, Crete Center for Theoretical Physics, Department of Physics, 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), Caltech Optical Observatories, California Institute of Technology, Department of Physics and Astronomy, SUNY Stony Brook, and Department of Astronomy, University of Maryland
Subjects: Cosmology and Nongalactic Astrophysics (astro-ph.CO), Infrared, media_common.quotation_subject, FOS: Physical sciences, Astrophysics, medicine.disease_cause, 01 natural sciences, Luminosity, Far infrared, 0103 physical sciences, medicine, 010303 astronomy & astrophysics, media_common, Physics, Luminous infrared galaxy, 010308 nuclear & particles physics, Star formation, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Galaxy, Space and Planetary Science, Sky, Astrophysics of Galaxies (astro-ph.GA), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Ultraviolet, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract: The Great Observatories All-sky LIRG Survey (GOALS) consists of a complete sample of 202 Luminous Infrared Galaxies (LIRGs) selected from the IRAS Revised Bright Galaxy Sample (RBGS). The galaxies span the full range of interaction stages, from isolated galaxies to interacting pairs to late stage mergers. We present a comparison of the UV and infrared properties of 135 galaxies in GOALS observed by GALEX and Spitzer. For interacting galaxies with separations greater than the resolution of GALEX and Spitzer (2-6"), we assess the UV and IR properties of each galaxy individually. The contribution of the FUV to the measured SFR ranges from 0.2% to 17.9%, with a median of 2.8% and a mean of 4.0 +/- 0.4%. The specific star formation rate of the GOALS sample is extremely high, with a median value (3.9*10^{-10} yr^{-1}) that is comparable to the highest specific star formation rates seen in the Spitzer Infrared Nearby Galaxies Survey sample. We examine the position of each galaxy on the IR excess-UV slope (IRX-beta) diagram as a function of galaxy properties, including IR luminosity and interaction stage. The LIRGs on average have greater IR excesses than would be expected based on their UV colors if they obeyed the same relations as starbursts with L_IR < 10^{11}L_0 or normal late-type galaxies. The ratio of L_IR to the value one would estimate from the IRXg-beta relation published for lower luminosity starburst galaxies ranges from 0.2 to 68, with a median value of 2.7. A minimum of 19% of the total IR luminosity in the RBGS is produced in LIRGs and ULIRGs with red UV colors (beta > 0). Among resolved interacting systems, 32% contain one galaxy which dominates the IR emission while the companion dominates the UV emission. Only 21% of the resolved systems contain a single galaxy which dominates both wavelengths., 37 pages, 10 figures, accepted for publication in ApJ
Published: 2010
Full Text: View/download PDF

23. SIMULATIONS OF MAGNETOHYDRODYNAMICS INSTABILITIES IN INTRACLUSTER MEDIUM INCLUDING ANISOTROPIC THERMAL CONDUCTION

Author: Tamara Bogdanovic, Christopher S. Reynolds, Ian J. Parrish, Steven A. Balbus, Department of Astronomy, University of Maryland, 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), and Astronomy Department and Theoretical Astrophysics Center, University of California, Berkeley
Subjects: Convection, Physics, Heat flux, Space and Planetary Science, Field line, Intracluster medium, Heat transfer, Astronomy and Astrophysics, Magnetohydrodynamics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Thermal conduction, Galaxy cluster, Computational physics
Abstract: We perform a suite of simulations of cooling cores in clusters of galaxies in order to investigate the effect of the recently discovered heat flux buoyancy instability (HBI) on the evolution of cores. Our models follow the three-dimensional magnetohydrodynamics of cooling cluster cores and capture the effects of anisotropic heat conduction along the lines of magnetic field, but do not account for the cosmological setting of clusters or the presence of active galactic nuclei (AGNs). Our model clusters can be divided into three groups according to their final thermodynamical state: catastrophically collapsing cores, isothermal cores, and an intermediate group whose final state is determined by the initial configuration of magnetic field. Modeled cores that are reminiscent of real cluster cores show evolution toward thermal collapse on a timescale which is prolonged by a factor of ∼2-10 compared with the zero-conduction cases. The principal effect of the HBI is to re-orient field lines to be perpendicular to the temperature gradient. Once the field has been wrapped up onto spherical surfaces surrounding the core, the core is insulated from further conductive heating (with the effective thermal conduction suppressed to less than 10-2 of the Spitzer value) and proceeds to collapse. We speculate that, in real clusters, the central AGN and possibly mergers play the role of "stirrers," periodically disrupting the azimuthal field structure and allowing thermal conduction to sporadically heat the core. © 2009. The American Astronomical Society. All rights reserved..
Published: 2009
Full Text: View/download PDF

24. SPITZER/IRS 5-35 μm LOW-RESOLUTION SPECTROSCOPY OF THE 12 μm SEYFERT SAMPLE

Author: Jiasheng Huang, Vassilis Charmandaris, Yanling Wu, Silvia Tommasin, Luigi Spinoglio, Infrared Processing Analysis Center, California Institute of Technology (IPAC), Crete Center for Theoretical Physics, Department of Physics, 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), Harvard-Smithsonian Center for Astrophysics, Istituto di Fisica dello Spazio Interplanetario (IFSI), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), and Dipartimento di Fisica, Università di Roma 1 La Sapienza
Subjects: Nuclear and High Energy Physics, Galaxies: Seyfert, Cosmology and Nongalactic Astrophysics (astro-ph.CO), Galaxies: active, Galaxies: starburst, Infrared: galaxies, Techniques: spectroscopic, Space and Planetary Science, Astronomy and Astrophysics, Infrared, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Spectral line, Spitzer Space Telescope, Astrophysics::Solar and Stellar Astrophysics, Spectroscopy, Spectrograph, Astrophysics::Galaxy Astrophysics, Physics, Star formation, Galaxy, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Equivalent width, Astrophysics - Cosmology and Nongalactic Astrophysics
Abstract: We present low-resolution 5.5-35 um spectra for 103 galaxies from the 12 um Seyfert sample, a complete unbiased 12 um flux limited sample of local Seyfert galaxies selected from the IRAS Faint Source Catalog, obtained with the Infrared Spectrograph (IRS) on-board Spitzer Space Telescope. For 70 of the sources observed in the IRS mapping mode, uniformly extracted nuclear spectra are presented for the first time. We performed an analysis of the continuum emission, the strength of the Polycyclic Aromatic Hydrocarbon (PAH) and astronomical silicate features of the sources. We find that on average, the 15-30 um slope of the continuum is alpha_{15-30}=-0.85+-0.61 for Seyfert 1s and -1.53+-0.84 for Seyfert 2s, and there is substantial scatter in each type. Moreover, nearly 32% of Seyfert 1s, and 9% of Seyfert 2s, display a peak in the mid-infrared spectrum at 20 um, which is attributed to an additional hot dust component. The PAH equivalent width decreases with increasing dust temperature, asindicated by the global infrared color of the host galaxies. However, no statistical difference in PAH equivalent width is detected between the two Seyfert types, 1 and 2, of the same bolometric luminosity. The silicate features at 9.7 and 18um in Seyfert 1 galaxies are rather weak, while Seyfert 2s are more likely to display strong silicate absorption. Those Seyfert 2s with the highest silicate absorption also have high infrared luminosity and high absorption (hydrogen column density N_H>10^23 cm^-2 as measured from the X-rays. Finally, we propose a new method to estimate the AGN contribution to the integrated 12 um galaxy emission, by subtracting the "star formation" component in the Seyfert galaxies, making use of the tight correlation between PAH 11.2 um luminosity and 12 um luminosity for star forming galaxies., accepted for publication in ApJ
Published: 2009
Full Text: View/download PDF

25. GALACTIC GLOBULAR AND OPEN CLUSTERS IN THE SLOAN DIGITAL SKY SURVEY. II. TEST OF THEORETICAL STELLAR ISOCHRONES

Author: Jennifer A. Johnson, Timothy C. Beers, Donald M. Terndrup, Marc H. Pinsonneault, Zeljko Ivezic, Deokkeun An, Inese I. Ivans, Franck Delahaye, Thomas Masseron, Department of Astronomy, Ohio State University, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Centre d'Etudes Lasers Intenses et Applications (CELIA), Université de Bordeaux (UB)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), 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), Department of Physics and Astrophysics, Center for the Study of Cosmic Evolution (CSCE) and Joint Institute for Nuclear Astrophysics (JINA), Michigan State University, Observatories of the Carnegie Institution of Washington, Department of Astronomy [Seattle], and University of Washington [Seattle]
Subjects: Physics, Series (mathematics), media_common.quotation_subject, Metallicity, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics - Astrophysics of Galaxies, Subdwarf, Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Sky, Astrophysics of Galaxies (astro-ph.GA), Globular cluster, Cluster (physics), Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, Open cluster, media_common
Abstract: We perform an extensive test of theoretical stellar models for main-sequence stars in ugriz, using cluster fiducial sequences obtained in the previous paper of this series. We generate a set of isochrones using the Yale Rotating Evolutionary Code (YREC) with updated input physics, and derive magnitudes and colors in ugriz from MARCS model atmospheres. These models match cluster main sequences over a wide range of metallicity within the errors of the adopted cluster parameters. However, we find a large discrepancy of model colors at the lower main sequence (Teff < ~4500 K) for clusters at and above solar metallicity. We also reach similar conclusions using the theoretical isochrones of Girardi et al. and Dotter et al., but our new models are generally in better agreement with the data. Using our theoretical isochrones, we also derive main-sequence fitting distances and turn-off ages for five key globular clusters, and demonstrate the ability to derive these quantities from photometric data in the Sloan Digital Sky Survey. In particular, we exploit multiple color indices (g - r, g - i, and g - z) in the parameter estimation, which allows us to evaluate internal systematic errors. Our distance estimates, with an error of sigma(m - M) = 0.03-0.11 mag for individual clusters, are consistent with Hipparcos-based subdwarf fitting distances derived in the Johnson-Cousins or Stromgren photometric systems., 26 pages, 28 figures. Accepted for publication in ApJ. Version with high resolution figures available at http://spider.ipac.caltech.edu/~deokkeun/sdss_iso.pdf
Published: 2009
Full Text: View/download PDF

26. Star Formation near Photodissociation Regions: Detection of a Peculiar Protostar near Cederblad 201

Author: Christine Joblin, David Teyssier, Olivier Berné, Javier R. Goicoechea, Maryvonne Gerin, 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), Centre d'étude spatiale des rayonnements (CESR), 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), European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS Paris), Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), and Université Fédérale Toulouse Midi-Pyrénées
Subjects: FOS: Physical sciences, stars: pre-main sequence, Astrophysics, Photodissociation region, 01 natural sciences, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Ionization, 0103 physical sciences, Protostar, 010306 general physics, 010303 astronomy & astrophysics, Physics, stars: formation, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], ISM: individual: B175/L1219 Ced 201 IRAS 22129+7000, Star formation, Astrophysics (astro-ph), Photodissociation, Astronomy and Astrophysics, Circumstellar envelope, ISM: jets and outflows, 13. Climate action, Space and Planetary Science, Spectral energy distribution, Outflow, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: International audience; We present the detection and characterization of a peculiar low-mass protostar (IRAS 22129+7000) located ~0.4 pc from the Cederblad 201 photodissociation region (PDR) and ~0.2 pc from the HH 450 jet. The cold circumstellar envelope surrounding the object has been mapped through its 1.2 mm dust continuum emission with IRAM 30 m/MAMBO. The deeply embedded protostar is clearly detected with Spitzer MIPS (70 mum), IRS (20-35 mum), and IRAC (4.5, 5.8, and 8 mum), but also in the Ks band (2.15 mum). Given the large near- and mid-IR excess in its spectral energy distribution, but large submillimeter-to-bolometric luminosity ratio (~=2%), IRAS 22129+7000 must be a transition Class 0/I source and/or a multiple stellar system. Targeted observations of several molecular lines from CO, 13CO, C18O, HCO+, and DCO+ have been obtained. The presence of a collimated molecular outflow mapped with the CSO telescope in the CO J=3-2 line suggests that the protostar/disk system is still accreting material from its natal envelope. Indeed, optically thick line profiles from high-density tracers such as HCO+ J=1-0 show a redshifted absorption asymmetry reminiscent of inward motions. We construct a preliminary physical model of the circumstellar envelope (including radial density and temperature gradients, velocity field, and turbulence) that reproduces the observed line profiles and estimates the ionization fraction. The presence of both mechanical and (nonionizing) far-ultraviolet (FUV) radiative input makes the region an interesting case to study triggered star formation.
Published: 2008
Full Text: View/download PDF

27. Curved Herbig‐Haro Jets: Simulations and Experiments

Author: Chantal Stehlé, Sergey Lebedev, Andrea Ciardi, David J. Ampleford, 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), Sandia National Laboratories, Centre for Cold Matter, Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ, (CCM), and Imperial College London
Subjects: Physics, Jet (fluid), Astrophysics::High Energy Astrophysical Phenomena, Astrophysics (astro-ph), FOS: Physical sciences, Astronomy and Astrophysics, Mechanics, Astrophysics, Bow shocks in astrophysics, Breakup, Rotation, Instability, Ram pressure, Degree of curvature, Space and Planetary Science, Herbig–Haro object, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics::Galaxy Astrophysics
Abstract: Herbig-Haro jets often show some degree of curvature along their path, in many cases produced by the ram pressure of a side-wind. We present simulations of both laboratory and astrophysical curved jets and experimental results from laboratory experiments. We discuss the properties and similarities of the laboratory and astrophysical flow, which show the formation of internal shocks and working surfaces. In particular the results illustrate how the break-up of the bow-shock and clumps in the flow are produced without invoking jet variability; we also discuss how jet rotation reduces the growth of the Rayleigh-Taylor instability in curved jets., 15 pages, 5 figure, accepted to be published in The Astrophysical Journal
Published: 2008
Full Text: View/download PDF

28. Laboratory and Astronomical Detection of the Negative Molecular Ion C3N−

Author: H. Gupta, Michael C. McCarthy, Carl A. Gottlieb, P. Thaddeus, Marcelino Agúndez, Sandra Brünken, M. Guelin, José Cernicharo, Harvard-Smithsonian Center for Astrophysics, Department of Molecular and Infrared Astrophysics, Consejo Superior de Investigaciones Científicas (DAMIR/CSIC), Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), 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), Dynamique des milieux interstellaires et plasmas stellaires, 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), and Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)
Subjects: Physics, Polyatomic ion, Green Bank Telescope, Astronomy and Astrophysics, Ion, law.invention, Radial velocity, Telescope, Wavelength, Space and Planetary Science, law, Millimeter, Atomic physics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Envelope (waves)
Abstract: The negative molecular ion C3N− has been detected at millimeter wavelengths in a low-pressure laboratory discharge, and then with frequencies derived from the laboratory data in the molecular envelope of IRC+10216. Spectroscopic constants derived from laboratory measurements of 12 transitions between 97 and 378 GHz allow the rotational spectrum to be calculated well into the submillimeter-wave band to 0.03 km s−1 or better in equivalent radial velocity. Four transitions of C3N− were detected in IRC+10216 with the IRAM 30 m telescope at precisely the frequencies calculated from the laboratory measurements. The column density of C3N− is 0.5% that of C3N, or approximately 20 times greater than that of C4H− relative to C4H. The C3N− abundance in IRC+10216 is compared with a chemical model calculation by Petrie & Herbst. An upper limit in TMC-1 for C3N− relative to C3N (
Published: 2008
Full Text: View/download PDF

29. Spatially ResolvedSpitzerIRS Spectroscopy of the Central Region of M82

Author: Bernhard R. Brandl, Vassilis Charmandaris, J. D. T. Smith, Lee Armus, Brent Groves, P. N. Appleton, James R. Houck, N. M. Förster Schreiber, P. Beirao, Leiden Observatory, NASA Herschel Science Center, California Institute of Technology (NHSC), Spitzer Science Center, California Institute of Technology (SSC), Max-Planck-Institut für Extraterrestriche Physik (MPE), Steward Observatory, University of Arizona, Institute of Electronic Structure and Laser, Foundation for Research and Technology-Hellas (IESL-FORTH), 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), and Department of Astronomy, Cornell University
Subjects: Physics, Stellar population, Star formation, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics (astro-ph), Extinction (astronomy), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Galactic plane, Galaxy, Spectral line, Space and Planetary Science, Astrophysics::Solar and Stellar Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Equivalent width, Caltech Library Services, Astrophysics::Galaxy Astrophysics, Line (formation)
Abstract: We present high spatial resolution (~ 35 parsec) 5-38 um spectra of the central region of M82, taken with the Spitzer Infrared Spectrograph. From these spectra we determined the fluxes and equivalent widths of key diagnostic features, such as the [NeII]12.8um, [NeIII]15.5um, and H_2 S(1)17.03um lines, and the broad mid-IR polycyclic aromatic hydrocarbon (PAH) emission features in six representative regions and analysed the spatial distribution of these lines and their ratios across the central region. We find a good correlation of the dust extinction with the CO 1-0 emission. The PAH emission follows closely the ionization structure along the galactic disk. The observed variations of the diagnostic PAH ratios across M82 can be explained by extinction effects, within systematic uncertainties. The 16-18um PAH complex is very prominent, and its equivalent width is enhanced outwards from the galactic plane. We interpret this as a consequence of the variation of the UV radiation field. The EWs of the 11.3um PAH feature and the H_2 S(1) line correlate closely, and we conclude that shocks in the outflow regions have no measurable influence on the H_2 emission. The [NeIII]/[NeII] ratio is on average low at ~0.18, and shows little variations across the plane, indicating that the dominant stellar population is evolved (5 - 6 Myr) and well distributed. There is a slight increase of the ratio with distance from the galactic plane of M82 which we attribute to a decrease in gas density. Our observations indicate that the star formation rate has decreased significantly in the last 5 Myr. The quantities of dust and molecular gas in the central area of the galaxy argue against starvation and for negative feedback processes, observable through the strong extra-planar outflows., Comment: 15 pages, 12 figures, 3 tables, ApJ, emulateapj
Published: 2008
Full Text: View/download PDF

30. SpitzerIRS Imaging and Spectroscopy of the Luminous Infrared Galaxy NGC 6052 (Mrk 297)

Author: D. G. Whelan, Daniel Devost, Vassilis Charmandaris, James R. Houck, Jason Marshall, Center for Radiophysics and Space Research, Cornell University (CRSR), Crete Center for Theoretical Physics, Department of Physics, 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: Luminous infrared galaxy, Physics, Line-of-sight, Infrared, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics (astro-ph), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Spectral line, Galaxy, Spitzer Space Telescope, Space and Planetary Science, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Tidal tail, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Spectroscopy, Astrophysics::Galaxy Astrophysics
Abstract: We present photometric and spectroscopic data of the interacting starburst galaxy NGC 6052 obtained with the Spitzer Space Telescope. The mid-infrared (MIR) spectra of the three brightest spatially resolved regions in the galaxy are remarkably similar and are consistent with dust emission from young nearly coeval stellar populations. Analysis of the brightest infrared region of the system, which contributes ~18.5 % of the total 16\micron flux, indicates that unlike similar off-nuclear infrared-bright regions found in Arp 299 or NGC 4038/9, its MIR spectrum is inconsistent with an enshrouded hot dust (T > 300K) component. Instead, the three brightest MIR regions all display dust continua of temperatures less than ~ 200K. These low dust temperatures indicate the dust is likely in the form of a patchy screen of relatively cold material situated along the line of sight. We also find that emission from polycyclic aromatic hydrocarbons (PAHs) and the forbidden atomic lines is very similar for each region. We conclude that the ionization regions are self-similar and come from young (about 6 Myr) stellar populations. A fourth region, for which we have no MIR spectra, exhibits MIR emission similar to tidal tail features in other interacting galaxies., 20 pages in preprint form, estimated 7 pages in ApJ Aeptember 10, 2007, v666n 2 issue, six encapsulated postscript figures
Published: 2007
Full Text: View/download PDF

31. BOW SHOCK FRAGMENTATION DRIVEN BY A THERMAL INSTABILITY IN LABORATORY ASTROPHYSICS EXPERIMENTS

Author: Edward Hansen, Rafael L. Rodríguez, P. de Grouchy, G. C. Burdiak, Andrea Ciardi, M. Bennett, Lee Suttle, Alejandro Frank, Francisco Suzuki-Vidal, Sergey Lebedev, Louisa Pickworth, J. Music, Jonathan Skidmore, Gareth Hall, George Swadling, Patrick Hartigan, G. Espinosa, J.M. Gil, S. N. Bland, The Royal Society, Blackett Laboratory, Imperial College London, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris), 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), Institut de signalisation, biologie du développement et cancer (ISBDC), Centre National de la Recherche Scientifique (CNRS)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA), Universidad Nacional Autónoma de México (UNAM), École normale supérieure - Paris (ENS-PSL), 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)-Centre National de la Recherche Scientifique (CNRS)-Université Côte d'Azur (UCA), and Universidad Nacional Autónoma de México = National Autonomous University of Mexico (UNAM)
Subjects: Shock wave, Radiative cooling, 0306 Physical Chemistry (Incl. Structural), Young stellar object, Astrophysics::High Energy Astrophysical Phenomena, PROPER MOTIONS, PLASMAS, FOS: Physical sciences, Astronomy & Astrophysics, HERBIG-HARO OBJECTS, Instability, 0305 Organic Chemistry, methods: laboratory: atomic, physics.plasm-ph, Radiative transfer, Supersonic speed, Herbig–Haro object, Astrophysics::Galaxy Astrophysics, ComputingMilieux_MISCELLANEOUS, Physics, [PHYS]Physics [physics], Science & Technology, NUMERICAL SIMULATIONS, Astronomy and Astrophysics, Mechanics, Plasma, shock waves, HUBBLE-SPACE-TELESCOPE, J.2.1, J.2.9, PROTOSTELLAR JETS, Physics - Plasma Physics, Plasma Physics (physics.plasm-ph), 85-05, 0201 Astronomical And Space Sciences, ISM: jets and outflows, Space and Planetary Science, instabilities, DENSITY, Physical Sciences, OPTICALLY THIN, SUPERSONIC JETS, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], RADIATIVE SHOCKS
Abstract: The role of radiative cooling during the evolution of a bow shock was studied in laboratory-astrophysics experiments that are scalable to bow shocks present in jets from young stellar objects. The laboratory bow shock is formed during the collision of two counter-streaming, supersonic plasma jets produced by an opposing pair of radial foil Z-pinches driven by the current pulse from the MAGPIE pulsed-power generator. The jets have different flow velocities in the laboratory frame and the experiments are driven over many times the characteristic cooling time-scale. The initially smooth bow shock rapidly develops small-scale non-uniformities over temporal and spatial scales that are consistent with a thermal instability triggered by strong radiative cooling in the shock. The growth of these perturbations eventually results in a global fragmentation of the bow shock front. The formation of a thermal instability is supported by analysis of the plasma cooling function calculated for the experimental conditions with the radiative packages ABAKO/RAPCAL., 9 pages, 5 figures, Accepted for publication in The Astrophysical Journal on 5th November 2015
Published: 2015
Full Text: View/download PDF

32. The Mid‐Infrared Properties of Starburst Galaxies fromSpitzer‐IRS Spectroscopy

Author: Brandl, B. R., Bernard-Salas, J., Spoon, Henrik W. W., Devost, Daniel, Sloan, G. C., Guilles, S., Wu, Y., Houck, J. R., Weedman, Dan W., Armus, Lee, Appleton, Philip N., Soifer, B. T., Charmandaris, Vassilis, Hao, Lei, Higdon, J. A., Marshall, S. J., Herter, T. L., Leiden University, Department of Astronomy, Cornell University, Spitzer Fellow, Spitzer Science Center, California Institute of Technology (SSC), 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), and Crete Center for Theoretical Physics, Department of Physics
Subjects: Physics, Infrared, Astronomy and Astrophysics, Starburst region, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Galaxy, Spectral line, Star cluster, Spitzer Space Telescope, Space and Planetary Science, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Spectral resolution, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Equivalent width, Astrophysics::Galaxy Astrophysics
Abstract: We present 5 38µm mid-infrared spectra at a spectral resolution of R � 65 130 of a large sample of 22 starburst nuclei taken with the Infrared Spectrograph IRS on board the Spitzer Space Telescope. The spectra show a vast range in starburst SEDs. The silicate absorption ranges from essentially no absorption to heavily obscured systems with an optical depth of �9.8µm � 5. The spectral slopes can be used to discriminate between starburst and AGN powered sources. The monochromatic continuum fluxes at 15µm and 30µm enable a remarkably accurate estimate of the total infrared luminosity of the starburst. We find that the PAH equivalent width is independent of the total starburst luminosity LIR as both continuum and PAH feature scale proportionally. However, the luminosity of the 6.2µm feature scales with LIR and can be used to approximate the total infrared luminosity of the starburst. Although our starburst sample covers about a factor of ten difference in the [NeIII]/[NeII] ratio, we found no systematic correlation between the radiation field hardness and the PAH equivalent width or the 7.7µm/11.3µm PAH ratio. These results are based on spatially integrated diagnostics over an entire starburst region, and local variations may be “averaged out”. It is presumably due to this effect that unresolved starburst nuclei with significantly different global properties appear spectrally as rather similar members of one class of objects. Subject headings: Telescopes: Spitzer, Galaxies: ISM, starburst, star clusters ISM: dust, extinction, HII regions
Published: 2006
Full Text: View/download PDF

33. Can Warm Neutral Medium Survive inside Molecular Clouds?

Author: Shu-ichiro Inutsuka, Patrick Hennebelle, 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), and Department of Physics, Kyoto University
Subjects: Physics, Photon, Hydrogen, Turbulence, Molecular cloud, chemistry.chemical_element, High resolution, Astronomy and Astrophysics, Astrophysics, Dissipation, chemistry, Space and Planetary Science, High pressure, Magnetohydrodynamics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics::Galaxy Astrophysics
Abstract: International audience; Recent high-resolution numerical simulations have suggested that the interstellar atomic hydrogen clouds have a complex two-phase structure. Since molecular clouds form through the contraction of H I gas, the question arises as to whether this structure is maintained in the molecular phase or not. Here we investigate whether the warm neutral atomic hydrogen can exist in molecular clouds. We calculate how far a piece of warm neutral medium (WNM) that is not heated by the UV photons could penetrate into the cloud and find that in the absence of any heating it is unlikely that a large fraction of the WNM would survive inside high-pressure molecular clouds. We then consider two possible heating mechanisms, namely, dissipation of turbulent energy and dissipation of MHD waves propagating in the WNM inside the cloud. We find that the second possibility is sufficient to allow the existence of WNM inside a molecular cloud of size ~=1 pc having pressure equal to ~=10PISM. This result suggests the possibility that channels of magnetized WNM may provide efficient energy injection for sustaining internal turbulence, which otherwise decays in a crossing time.
Published: 2006
Full Text: View/download PDF

34. Probing Cosmic Star Formation Using Long Gamma‐Ray Bursts: New Constraints from theSpitzer Space Telescope

Author: Daniel Devost, William J. Forrest, E. Le Floc'h, Lee Armus, F. Mirabel, V. Charmandaris, Steward Observatory, University of Arizona, 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), Crete Center for Theoretical Physics, Department of Physics, Department of Physics and Astronomy, University of Rochester, European Southern Observatory, Spitzer Science Center, California Institute of Technology (SSC), and Center for Radiophysics and Space Research, Cornell University (CRSR)
Subjects: Physics, education.field_of_study, Star formation, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics (astro-ph), Population, FOS: Physical sciences, Astronomy and Astrophysics, Context (language use), Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Redshift, Galaxy, Spitzer Space Telescope, Space and Planetary Science, Galaxy formation and evolution, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Gamma-ray burst, education, Astrophysics::Galaxy Astrophysics
Abstract: We report on IRAC-4.5mic, IRAC-8.0mic and MIPS-24mic deep observations of 16 Gamma-Ray Burst (GRBs) host galaxies performed with the Spitzer Space Telescope, and we investigate in the thermal infrared the presence of evolved stellar populations and dust-enshrouded star-forming activity associated with these objects. Our sample is derived from GRBs that were identified with sub-arcsec localization between 1997 and 2001, and only a very small fraction (~20%) of the targeted sources is detected down to f_4.5mic ~3.5microJy and f_24mic ~85microJy (3sigma). This likely argues against a population dominated by massive and strongly-starbursting (i.e., SFR > ~100 Msol/yr) galaxies as it has been recently suggested from submillimeter/radio and optical studies of similarly-selected GRB hosts. Furthermore we find evidence that some GRBs do not occur in the most infrared-luminous regions -- hence the most actively star-forming environments -- of their host galaxies. Should the GRB hosts be representative of all star-forming galaxies at high redshift, models of infrared galaxy evolution indicate that > ~50% of GRB hosts should have f_24mic > ~100microJy. Unless the identification of GRBs prior to 2001 was prone to strong selection effects biasing our sample against dusty galaxies, we infer in this context that the GRBs identified with the current techniques can not be directly used as unbiased probes of the global and integrated star formation history of the Universe., ApJ in press, 23 pages, 8 figures (scheduled for the ApJ 10 May 2006, v642 2 issue). Full resolution available at http://perceval.as.arizona.edu/~elefloch/Publis/ms_grb_spitzer.pdf
Published: 2006
Full Text: View/download PDF

35. 16 μm Imaging around the Hubble Deep Field–North with theSpitzerIRS

Author: James W. Colbert, R.-R. Chary, L. Armus, Vassilis Charmandaris, Dan Weedman, Harry Teplitz, Spitzer Science Center, California Institute of Technology (SSC), 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: Photometry (optics), Physics, Space and Planetary Science, Infrared, Hubble Deep Field, Flux, Astronomy and Astrophysics, Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Flux ratio, Redshift, Luminosity
Abstract: International audience; We present a pilot study of 16 mum imaging within the GOODS northern field. Observations were obtained using the ``peak-up'' imaging capability of the Spitzer IRS. We survey 35 arcmin2 to an average 3 sigma depth of 0.075 mJy and detect 149 sources. The survey partially overlaps the area imaged at 15 mum by the ISO, and we demonstrate that our photometry and galaxy number counts are consistent with its measurements. We infer the total infrared luminosity of 16 mum detections using a comparison to local templates and find a wide range of LIR, from ~109 to 1012 Lsolar. Approximately 1/5 of the detected sources have counterparts in the Chandra 2 Ms catalog, and we show that the hard-band (2-8 keV) detected sources are likely to have strong active galactic nucleus (AGN) contributions to the X-ray flux. The ultradeep sensitivity of Chandra implies that some X-ray detections may be purely starbursting objects. We examine the 16 to 24 mum flux ratio and conclude that it shows evidence for the detection of redshifted polycyclic aromatic hydrocarbon (PAH) emission at z~0.5 and z>0.8.
Published: 2005
Full Text: View/download PDF

36. Identifying Silicate-absorbed ULIRGs at z ~ 1-2 in the Bootes Field Using the Spitzer IRS

Author: Dan Weedman, J. R. Houck, Harry Teplitz, E. Le Floc'h, Lee Armus, Mansi M. Kasliwal, S. J. U. Higdon, V. Charmandaris, 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), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Steward Observatory, University of Arizona, and Spitzer Science Center, California Institute of Technology (SSC)
Subjects: Luminous infrared galaxy, Physics, education.field_of_study, Infrared, Astrophysics (astro-ph), Population, FOS: Physical sciences, Spectral density, Astronomy and Astrophysics, BOOTES, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Redshift, Space and Planetary Science, Galaxy formation and evolution, Astrophysics::Earth and Planetary Astrophysics, Absorption (logic), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], education, Astrophysics::Galaxy Astrophysics
Abstract: Using the 16$\mu$m peakup imager on the Infrared Spectrograph (IRS) on Spitzer, we present a serendipitous survey of 0.0392 deg$^{2}$ within the area of the NOAO Deep Wide Field Survey in Bootes. Combining our results with the available Multiband Imaging Photometer for Spitzer (MIPS) 24$\mu$m survey of this area, we produce a catalog of 150 16$\mu$m sources brighter than 0.18 mJy (3$\sigma$) for which we derive measures or limits on the 16/24$\mu$m colors. Such colors are especially useful in determining redshifts for sources whose mid infrared spectra contain strong emission or absorption features that characterize these colors as a function of redshift. We find that the 9.7$\mu$m silicate absorption feature in Ultraluminous Infrared Galaxies (ULIRGs) results in sources brighter at 16$\mu$m than at 24$\mu$m at z $\sim$ 1--1.8 by at least 20%. With a threshold flux ratio of 1.2, restricting our analysis to $>5\sigma$ detections at 16$\mu$m, and using a $3\sigma$ limit on 24$\mu$m non-detections, the number of silicate-absorbed ULIRG candidates is 36. This defines a strong upper limit of $\sim$920 sources deg$^{-2}$, on the population of silicate-absorbed ULIRGs at z $\sim$ 1--1.8. This source count is about half of the total number of sources predicted at z $\sim$ 1--2 by various phenomenological models. We note that the high 16/24$\mu$m colors measured cannot be reproduced by any of the mid-IR spectral energy distributions assumed by these models, which points to the strong limitations currently affecting our phenomenological and theoretical understanding of infrared galaxy evolution., Comment: Accepted for Publication in Astrophysical Journal Letters 4 pages, 2 figures, 1 table
Published: 2005
Full Text: View/download PDF

37. The Interacting Galaxy Pair NGC 5394/95: Near-Infrared Photometry, Structure, and Morphology

Author: Izbeth Hernández-López, M. Valdez-Gutierrez, Ivânio Puerari, Instituto Nacional de Astrofísica Óptica y Electrónica (INAOE), Departamento de Astronomía, Universidad de Guanajuato, 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: Luminous infrared galaxy, Physics, Near-infrared spectroscopy, Astronomy, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Galaxy, Hubble sequence, Photometry (optics), symbols.namesake, Space and Planetary Science, Fourier analysis, Bulge, symbols, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Fourier series, Astrophysics::Galaxy Astrophysics
Abstract: International audience; We present near-infrared observations in the J, H, and K' passbands of the interacting pair of galaxies NGC 5394/95 (KPG 404). The total magnitudes, colors, surface brightnesses, and color profiles are calculated. In addition, aperture magnitudes are compared against previous determinations. We also perform a structural (disk + bulge) analysis, as well as a two-dimensional Fourier analysis, to gain insight into the morphology of the pair. The disk + bulge fit shows that NGC 5394 (KPG 404A) is more compact than normal galaxies, while NGC 5395 (KPG 404B) is less concentrated. The two-dimensional Fourier analysis shows that NGC 5394 is an H2beta galaxy in the dust-penetrated (DP) classification by Block & Puerari. NGC 5395, in contrast, displays a very complex structure that needs a number of Fourier coefficients to be explained. A tightly wound m=1 coefficient (DP class H1alpha) is the main structure, but other m=1 and m=2 coefficients (suggesting modulation) are also present in the Fourier spectra. The m=1 coefficients represent a pseudo-ring-type structure, indicative of a collision rather than a passage. Based on our results we are able to assert that the scenario of the interaction between the galaxy members of KPG 404 should take into account a crossing of NGC 5394 through the disk of NGC 5395 in a Cartwheel-like encounter rather than a passage as in M51-type pairs. Numerical simulations could help to unravel the structural and morphological evolution of this interacting pair.
Published: 2005
Full Text: View/download PDF

38. Observational Evidence of the Formation of Cyanopolyynes in CRL 618 through the Polymerization of HCN

Author: Juan R. Pardo, Javier R. Goicoechea, José Cernicharo, Departamento de Astrofisica Molecular e Infrarroja-Instituto de Estructura de la Materia, Consejo Superior de Investigaciones Científica (CSIC), 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: Chemical models, FOS: Physical sciences, Astrophysics, Radio lines: stars, chemistry.chemical_compound, Observational evidence, Atmospheric radiative transfer codes, individual (CRL 618) [Stars], molecules [ISM], Astrochemistry, Physics, stars [Radio lines], Cyanopolyyne, Astrophysics (astro-ph), Stars: AGB and post-AGB, Astronomy and Astrophysics, Circumstellar matter, AGB and post-AGB [Stars], Planetary nebula, ISM: molecules, Stars: carbon, Stars, chemistry, Space and Planetary Science, Excited state, Stars: individual (CRL 618), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], carbon [Stars], Order of magnitude
Abstract: The abundance ratio of consecutive members of the cyanopolyyne family has been explored in CRL 618 using data acquired in a complete line survey covering the frequency range 81–356 GHz. The Jup range explored for the different molecules is 1–4 for HCN and HNC, 9–39 for HC3N, 31–133 for HC5N, and 72–85 for HC7N (not detected beyond Jup=85). The lowest vibrationally excited state of HC7N (nu_15 at 62 cm^-1) has been tentatively detected. Data analysis has been performed by extending our previous geometric and radiative transfermodel of the slowly expanding envelope (SEE) surrounding the compact central continuum source of CRL 618, which was established from the study of rotational lines in several vibrationally excited states of HC3N. The new lines analyzed here require modeling of the high-velocity wind (HVW) component and the colder circumstellar gas, a remnant of the AGB phase of CRL 618. The derived HC3N/HC5N and HC5N/HC7N abundance ratios from this set of uniformly calibrated lines are between ~3 and 6 in the different regions, similar to standard values in the circumstellar and interstellar media and consistent with previous estimates obtained from ISO observations and chemical models. However, the abundance ratios of HC3N, HC5N, and HC7N with respect to HCN are at least 2 orders of magnitude larger than those typical for AGB C-rich stars, such as IRC +10216. This fact indicates that in the short transition toward the planetary nebula phase, HCN is quickly reprocessed into longer cyanopolyyne chains. A similar behavior was previously found in this object for the polyacetylenic chains (C2nH2)., We acknowledge the support of the IRAM 30 m staff during the long completion of the line survey. CSO operations are supported by US NSF grant AST 22-09008. This work has also been supported by Spanish DGES and PNIE grants ESP 2002-01627, AYA 2002-10113-E, and AYA 2003-02785-E.
Published: 2005
Full Text: View/download PDF

39. Very Large Array H92α and H53α Radio Recombination Line Observations of M82

Author: J. H. Zhao, C. A. Rodriguez-Rico, K. R. Anantharamaiah, F. Viallefond, W. M. Goss, National Radio Astronomy Observatory, Socorro (NRAO), 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), Harvard-Smithsonian Center for Astrophysics, and Raman Research Institute
Subjects: Physics, Plane (geometry), Velocity gradient, Continuum (design consultancy), Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Galaxy, Space and Planetary Science, Ionization, Outflow, Halo, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Astrophysics::Galaxy Astrophysics, Line (formation)
Abstract: International audience; We present high angular resolution (0.6") observations made with the Very Large Array of the radio continuum at 8.3 and 43 GHz, as well as H92alpha and H53alpha radio recombination lines from the nearby (~3 Mpc) starburst galaxy M82. In the continuum we identify 58 sources at 8.3 GHz, of which 19 have no counterparts in catalogs published at other frequencies. At 43 GHz we identify 18 sources, unresolved at 0.6" resolution, of which five were unknown previously. The spatial distribution of the H92alpha line is inhomogeneous; we identify 27 features; about half of them are associated with continuum emission sources. Their sizes are typically in the range 2-10 pc. Although observed with poorer signal-to-noise ratio, the H53alpha line is detected. The line and continuum emission are modeled using a collection of H II regions at different distances from the nucleus. The observations can be interpreted assuming a single-density component, but equally well with two components if constraints originating from previous high-resolution continuum observations are used. The high-density component has a density of ~4×104 cm-3. However, the bulk of the ionization is in regions with densities that are typically a factor of 10 lower. The gas kinematics, using the H92alpha line, confirms the presence of steep velocity gradient (26 km s-1 arcsec-1) in the nuclear region, as previously reported, in particular from observations of the [Ne II] line at 12 mum. This gradient has about the same amplitude on both sides of the nucleus. Since this steep gradient is observed not only on the major axis but also at large distances along a band at P.A.~150deg, the interpretation in terms of x2 orbits elongated along the minor axis of the bar, which would be observed at an angle close to the inclination of the main disk, seems inadequate. The observed kinematics cannot be modeled using a simple model that consists of a set of circular orbits observed at different tilt angles. Ad hoc radial motions must be introduced to reproduce the pattern of the velocity field. Different families of orbits are indicated since we detect a signature in the kinematics at the transition between the two plateaus observed in the NIR light distribution. These H92alpha data also reveal the base of the outflow where the injection toward the halo on the northern side occurs. The outflow has a major effect on the observed kinematics, present even in the disk at distances close to the nucleus. The kinematic pattern suggests a connection between the gas flowing in the plane of M82 toward the center; this behavior most likely is due to the presence of a bar and the outflow out of the plane.
Published: 2004
Full Text: View/download PDF

40. Evolution of Self‐Gravitating Magnetized Disks. I. Axisymmetric Simulations

Author: Steven A. Balbus, Sebastien Fromang, Jean-Pierre De Villiers, 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), Department of Astronomy, Virginia Institute of Theoretical Astronomy, University of Virginia, 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: Physics, Angular momentum, Turbulence, Astrophysics (astro-ph), Rotational symmetry, FOS: Physical sciences, Astronomy and Astrophysics, Torus, Mechanics, Astrophysics, 01 natural sciences, Space and Planetary Science, Magnetorotational instability, 0103 physical sciences, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010306 general physics, Global structure, Linear growth, 010303 astronomy & astrophysics, Coherence (physics)
Abstract: In this paper and a companion work, we report on the first global numerical simulations of self-gravitating magnetized tori, subject in particular to the influence of the magnetorotational instability (MRI). In this work, paper I, we restrict our calculations to the study of the axisymmetric evolution of such tori. Our goals are twofold: (1) to investigate how self-gravity influences the global structure and evolution of the disks; and (2) to determine whether turbulent density inhomogeneities can be enhanced by self-gravity in this regime. As in non self-gravitating models, the linear growth of the MRI is followed by a turbulent phase during which angular momentum is transported outward. As a result, self-gravitating tori quickly develop a dual structure composed of an inner thin Keplerian disk fed by a thicker self-gravitating disk, whose rotation profile is close to a Mestel disk. Our results show that the effects of self-gravity enhance density fluctuations much less than they smooth the disk, and giving it more coherence. We discuss the expected changes that will occur in 3D simulations, the results of which are presented in a companion paper., 20 pages, 7 figures, accepted for publication in ApJ
Published: 2004
Full Text: View/download PDF

41. Laboratory Detection of the Lyβ 1150 Å Quasi-molecular Satellite Seen in Far Ultraviolet Spectroscopic Explorer Observations of the White Dwarf G226-29

Author: N. F. Allard, J. Huber, John F. Kielkopf, Department of Physics, University of Louisville, 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'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: Physics, Hydrogen, Absorption spectroscopy, Stellar atmosphere, Astronomy, White dwarf, chemistry.chemical_element, Astronomy and Astrophysics, Molecular orbital theory, Plasma, Astrophysics, Spectral line, chemistry, Space and Planetary Science, Astrophysics::Solar and Stellar Astrophysics, Physics::Atomic Physics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Absorption (electromagnetic radiation)
Abstract: International audience; We report a laboratory measurement of the 1150 Å collision-induced quasi-molecular satellite of Lybeta. It was first identified in Far Ultraviolet Spectroscopic Explorer observations of the cool DA white dwarf G226-29. The satellite, predicted by theoretical calculations of the complete profile of the hydrogen Lyalpha and Lybeta lines, arises from transitions occurring during close collisions of hydrogen atoms. Fits of model atmospheres with these profiles to observed spectra provide accurate constraints on stellar temperature and gravity. The comparison here of the far-ultraviolet absorption spectrum of a laser-produced hydrogen plasma with the theoretical absorption profiles and a model of the plasma confirms the underpinning atomic and molecular theory.
Published: 2004
Full Text: View/download PDF

42. Far Ultraviolet Spectroscopic ExplorerObservation of the Ultramassive White Dwarf PG 1658+441

Author: J. Dupuis, Pierre Chayer, Guillaume Hébrard, Stephane Vennes, N. F. Allard, 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'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: Stars: Individual: Alphanumeric: PG 1658+441, Physics, Stars: White Dwarfs, Solar mass, Far ultraviolet, Line: Profiles, Balmer series, White dwarf, Stars: Abundances, Astronomy and Astrophysics, Astrophysics, symbols.namesake, [SDU]Sciences of the Universe [physics], Space and Planetary Science, symbols, Fuse (electrical), Satellite, Ultraviolet: Stars
Abstract: International audience; We present an analysis of the Far Ultraviolet Spectroscopic Explorer (FUSE) spectrum of the ultramassive (M=1.31 Msolar), magnetic (Bs=2.3 MG) white dwarf PG 1658+441. The far-ultraviolet (FUV) spectrum exhibits very broad Lyman lines and quasi-molecular Lyβ satellites, but weak Lyγ satellites may also be present. PG 1658+441 is the hottest white dwarf known to show these satellite features. We fit the Lyman lines with stellar models and obtain atmospheric parameters consistent with a published analysis of the Balmer lines. By averaging results obtained for the different FUSE segments, we determine Teff=29,620+/-500 K and logg=9.31+/-0.07. The models match the data over large portions of the spectrum, but discrepancies remain near the satellite features. Finally, no trace elements have been identified in the FUV spectrum, and we provide abundance upper limits for C, N, Si, and P.
Published: 2003
Full Text: View/download PDF

43. Detection of Dark Matter Skewness in the VIRMOS‐DESCART Survey: Implications for Ω0

Author: Yannick Mellier, Tong-Jie Zhang, Ludovic Van Waerbeke, Pengjie Zhang, John Dubinski, Ue-Li Pen, 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'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: Physics, 010308 nuclear & particles physics, Cosmology: Dark Matter- Cosmology: Gravitational Lensing, Gaussian, Dark matter, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, Cosmology: Observations, 01 natural sciences, Omega, Measure (mathematics), symbols.namesake, Distribution (mathematics), Cosmology: Large-Scale Structure of Universe, [SDU]Sciences of the Universe [physics], Space and Planetary Science, Skewness, 0103 physical sciences, symbols, Degeneracy (mathematics), 010303 astronomy & astrophysics, Weak gravitational lensing, Cosmology: Theory
Abstract: Weak gravitational lensing provides a direct statistical measure of the dark matter distribution. The variance is easiest to measure, which constrains the degenerate product \sigma_8\Omega^0.6. The degeneracy is broken by measuring the skewness arising from the fact that densities must remain positive, which is not possible when the initially symmetric perturbations become non-linear. Skewness measures the non-linear mass scale, which in combination with the variance measures \Omega directly. We present the first detection of dark matter skewness from the Virmos-Decart survey. We have measured the full three point function, and its projections onto windowed skewness. We separate the lensing mode and the B mode. The lensing skewness is detected for a compensated Gaussian on scales of 5.37 arc minutes to be \kappa^3=1.06+/-0.06x10^-6. The B-modes are consistent with zero at this scale. The variance for the same window function is \kappa^2= 5.32+/-0.62+/-0.98x10^-5, resulting in S_3=375^{+342}_{-124}. Comparing to N-body simulations, we find \Omega_0, Comment: 26 pages 8 figures, accepted by ApJ, minor revisions, corrected eqn (21)
Published: 2003
Full Text: View/download PDF

44. Deep, Broadband Spectral Line Surveys of Molecule-rich Interstellar Clouds

Author: Brian M. Hays, Nadine Wehres, M. C. Sumner, Dariusz C. Lis, James L. Sanders, Mary L. Rad, Jacob C. Laas, Susanna L. Widicus Weaver, Trevor Cross, Jay A. Kroll, Luyao Zou, Brett A. McGuire, 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), and École normale supérieure - Paris (ENS Paris)
Subjects: [PHYS]Physics [physics], Physics, Astrochemistry, 010504 meteorology & atmospheric sciences, Interstellar cloud, Astronomy, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, 7. Clean energy, Spectral line, Interstellar medium, Wavelength, Caltech Submillimeter Observatory, 13. Climate action, Space and Planetary Science, 0103 physical sciences, Broadband, Emission spectrum, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences
Abstract: Spectral line surveys are an indispensable tool for exploring the physical and chemical evolution of astrophysical environments due to the vast amount of data that can be obtained in a relatively short amount of time. We present deep, broadband spectral line surveys of 30 interstellar clouds using two broadband λ = 1.3 mm receivers at the Caltech Submillimeter Observatory. This information can be used to probe the influence of physical environment on molecular complexity. We observed a wide variety of sources to examine the relative abundances of organic molecules as they relate to the physical properties of the source (i.e., temperature, density, dynamics, etc.). The spectra are highly sensitive, with noise levels ≤25 mK at a velocity resolution of ~0.35 km s^(−1). In the initial analysis presented here, column densities and rotational temperatures have been determined for the molecular species that contribute significantly to the spectral line density in this wavelength regime. We present these results and discuss their implications for complex molecule formation in the interstellar medium.
Published: 2017
Full Text: View/download PDF

45. ALMA Mapping of Rapid Gas and Dust Variations in Comet C/2012 S1 (ISON):New Insights into the Origin of Cometary HNC

Author: Dariusz C. Lis, Iain Coulson, Dominique Bockelée-Morvan, Anthony J. Remijan, Jacques Crovisier, Martin A. Cordiner, Lucas Paganini, Geronimo L. Villanueva, Nicolas Biver, Steven B. Charnley, Yi-Jehng Kuan, Jérémie Boissier, Stefanie N. Milam, M. J. Mumma, Biologie et écologie tropicale et méditerranéenne [2007-2010] (BETM), Université de Perpignan Via Domitia (UPVD)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), NASA Goddard Space Flight Center (GSFC), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris), 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), 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), Université de Perpignan Via Domitia (UPVD)-École Pratique des Hautes Études (EPHE), and École normale supérieure - Paris (ENS-PSL)
Subjects: Earth and Planetary Astrophysics (astro-ph.EP), [PHYS]Physics [physics], Physics, 010504 meteorology & atmospheric sciences, Molecular line, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Submillimeter Array, medicine.anatomical_structure, 13. Climate action, Space and Planetary Science, 0103 physical sciences, medicine, Outflow, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, Nucleus, ComputingMilieux_MISCELLANEOUS, Astrophysics - Earth and Planetary Astrophysics, 0105 earth and related environmental sciences, Production rate
Abstract: Observations of the sungrazing comet C/2012 S1 (ISON) were carried out using the Atacama Large Millimeter/submillimeter Array (ALMA) at a heliocentric distance of 0.58-0.54 AU (pre-perihelion) on 2013 November 16-17. Temporally resolved measurements of the coma distributions of HNC, CH$_3$OH, H$_2$CO and dust were obtained over the course of about an hour on each day. During the period UT 10:10-11:00 on Nov. 16, the comet displayed a remarkable drop in activity, manifested as a $>42$% decline in the molecular line and continuum fluxes. The H$_2$CO observations are consistent with an abrupt, $\approx50$% reduction in the cometary gas production rate soon after the start of our observations. On Nov. 17, the total observed fluxes remained relatively constant during a similar period, but strong variations in the morphology of the HNC distribution were detected as a function of time, indicative of a clumpy, intermittent outflow for this species. Our observations suggest that at least part of the detected HNC originated from degradation of nitrogen-rich organic refractory material, released intermittently from confined regions of the nucleus. By contrast, the distributions of CH$_3$OH and H$_2$CO during the Nov. 17 observations were relatively uniform, consistent with isotropic outflow and stable activity levels for these species. These results highlight a large degree of variability in the production of gas and dust from comet ISON during its pre-perihelion outburst, consistent with repeated disruption of the nucleus interspersed with periods of relative quiescence., 9 pages. Accepted for publication in ApJ, February 2017
Published: 2017
Full Text: View/download PDF

46. Herschel HIFI observations of O2toward Orion: Special conditions for shock enhanced emission

Author: Pierre Encrenaz, Arnold O. Benz, John H. Black, Åke Hjalmarson, Serena Viti, Dariusz C. Lis, Jo-Hsin Chen, David A. Neufeld, Paul F. Goldsmith, Ewine F. van Dishoeck, Laurent Pagani, David Hollenbach, Edith Falgarone, Floris van der Tak, Umut A. Yildiz, Gary J. Melnick, Paola Caselli, Michael J. Kaufman, Edwin A. Bergin, Ronald L. Snell, Javier R. Goicoechea, Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris), 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), Harvard-Smithsonian Center for Astrophysics (CfA), Harvard University [Cambridge]-Smithsonian Institution, Onsala Space Observatory (OSO), Chalmers University of Technology [Göteborg], INAF - Osservatorio Astrofisico di Arcetri (OAA), Istituto Nazionale di Astrofisica (INAF), SRON Netherlands Institute for Space Research (SRON), Leiden Observatory [Leiden], Universiteit Leiden [Leiden], Astronomy, NASA-California Institute of Technology (CALTECH), École normale supérieure - Paris (ENS-PSL), Harvard University-Smithsonian Institution, and Universiteit Leiden
Subjects: 010504 meteorology & atmospheric sciences, media_common.quotation_subject, Interstellar cloud, FOS: Physical sciences, Flux, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Radiation, 01 natural sciences, 7. Clean energy, law.invention, Shock waves, law, 0103 physical sciences, Maser, 010303 astronomy & astrophysics, molecules [ISM], ComputingMilieux_MISCELLANEOUS, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, media_common, Line (formation), Astrochemistry, [PHYS]Physics [physics], Physics, Line-of-sight, Molecular cloud, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, ISM: molecules, 13. Climate action, Space and Planetary Science, Sky, Astrophysics of Galaxies (astro-ph.GA), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: We report observations of molecular oxygen (O$_2$) rotational transitions at 487 GHz, 774 GHz, and 1121 GHz toward Orion Peak A. The O2 lines at 487 GHz and 774 GHz are detected at velocities of 10-12 km/s with line widths 3 km/s; however, the transition at 1121 GHz is not detected. The observed line characteristics, combined with the results of earlier observations, suggest that the region responsible for the O$_2$ emission is 9" (6e16 cm) in size, and is located close to the H2 Peak 1position (where vibrationally-excited H$_2$ emission peaks), and not at Peak A, 23" away. The peak O2 column density is 1.1e18/cm2. The line velocity is close to that of 621 GHz water maser emission found in this portion of the Orion Molecular Cloud, and having a shock with velocity vector lying nearly in the plane of the sky is consistent with producing maximum maser gain along the line-of-sight. The enhanced O$_2$ abundance compared to that generally found in dense interstellar clouds can be explained by passage of a low-velocity C-shock through a clump with preshock density 2e4/cm3, if a reasonable flux of UV radiation is present. The postshock O$_2$ can explain the emission from the source if its line of sight dimension is ~10 times larger than its size on the plane of the sky. The special geometry and conditions required may explain why O$_2$ emission has not been detected in the cores of other massive star-forming molecular clouds., 28 pages, 13 figures
Published: 2014
Full Text: View/download PDF

47. Connection between dynamically derived Initial Mass Function normalization and stellar population parameters

Author: Richard M. McDermid, Anne-Marie Weijmans, Tom Oosterloo, Lisa M. Young, Alison F. Crocker, Sadegh Khochfar, Eric Emsellem, P. T. de Zeeuw, Katherine Alatalo, Maxime Bois, Davor Krajnović, Leo Blitz, Pierre-Alain Duc, Frédéric Bournaud, Michele Cappellari, Harald Kuntschner, Raffaella Morganti, Timothy A. Davis, Paolo Serra, Nicholas Scott, Roger L. Davies, Thorsten Naab, Martin Bureau, Marc Sarzi, E. Bayet, Sub-department of Astrophysics [Oxford], Department of Physics [Oxford], University of Oxford [Oxford]-University of Oxford [Oxford], Department of Astronomy [Berkeley], University of California [Berkeley], University of California-University of California, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris), 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), Centre de Recherche Astrophysique de Lyon (CRAL), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), 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), European Southern Observatory (ESO), Max-Planck-Institut für Extraterrestrische Physik (MPE), Kapteyn Astronomical Institute [Groningen], University of Groningen [Groningen], Max-Planck-Institut für Astrophysik (MPA), Max-Planck-Gesellschaft, Netherlands Institute for Radio Astronomy (ASTRON), Centre for Astrophysics Research [Hatfield], University of Hertfordshire [Hatfield] (UH), CSIRO Astronomy and Space Science, Commonwealth Scientific and Industrial Research Organisation [Canberra] (CSIRO), Dunlap Institute for Astronomy and Astrophysics [Toronto], University of Toronto, Astronomy, University of St Andrews. School of Physics and Astronomy, University of Oxford-University of Oxford, University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), École normale supérieure - Paris (ENS-PSL), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), and 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)
Subjects: Initial mass function, Stellar population, Metallicity, Population, abundances [Galaxies], Astrophysics, elliptical and lenticular, cD [Galaxies], Measure (mathematics), Spectral line, cD, QB Astronomy, Spectral analysis, galaxies: elliptical and lenticular, education, QC, galaxies: kinematics and dynamics, ComputingMilieux_MISCELLANEOUS, QB, Physics, [PHYS]Physics [physics], education.field_of_study, kinematics and dynamics [Galaxies], Astronomy and Astrophysics, Galaxy, QC Physics, Space and Planetary Science, galaxies: stellar content, stellar content [Galaxies], galaxies: abundances, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: The authors thank the referee for helping to improve this article. The research leading to these results has received funding from the European Community’s Seventh Framework Programme (/FP7/2007-2013/) under grant agreement No 229517. MC acknowledges support from a Royal Society University Research Fellowship. This work was supported by the rolling grants PP/E001114/1 and ST/H002456/1 and visitors grants PPA/V/S/2002/00553, PP/E001564/1 and ST/H504862/1 from the UK Research Councils. RLD acknowledges grants from Christ Church, Oxford and support from the Royal Society Wolfson Merit Award 502011.K502/jd. SK acknowledges support from the Royal Society Joint Projects Grant JP0869822. TN and MBois acknowledge support from the DFG Cluster of Excellence ‘Origin and Structure of the Universe’. MS acknowledges support from a STFC Advanced Fellowship ST/F009186/1. LY acknowledges support from NSF grant AST-1109803. The authors acknowledge financial support from ESO. We report on empirical trends between the dynamically determined stellar initial mass function (IMF) and stellar population properties for a complete, volume-limited sample of 260 early-type galaxies from the Atlas3D project. We study trends between our dynamically-derived IMF normalisation and absorption line strengths, and interpret these via single stellar population- (SSP-) equivalent ages, abundance ratios(measured as [alpha/Fe]), and total metallicity, [Z/H]. We find that old and alpha-enhanced galaxies tend to have on average heavier (Salpeter-like) mass normalisation of the IMF, but stellar population does not appear to be a good predictor of the IMF, with a large range of normalisation at a given population parameter. As a result, we find weak IMF-[alpha/Fe] and IMF-age correlations, and no significant IMF-[Z/H]correlation. The observed trends appear significantly weaker than those reported in studies that measure the IMF normalisation via low-mass star demographics inferred through stellar spectral analysis. Postprint
Published: 2014
Full Text: View/download PDF

48. Confirmation of circumstellar phosphine

Author: Pierre Encrenaz, José Cernicharo, Marcelino Agúndez, D. Teyssier, Leen Decin, Ministerio de Ciencia e Innovación (España), SSE 2014, Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB), Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Instituut voor Sterrenkunde [Leuven], Catholic University of Leuven - Katholieke Universiteit Leuven (KU Leuven), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS Paris), 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), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), and École normale supérieure - Paris (ENS-PSL)
Subjects: Solar System, Infrared, Line: identification, individual (IRC+10216) [stars], FOS: Physical sciences, Rotational transition, Astrophysics, Stars: individual (IRC +10216), 010402 general chemistry, 01 natural sciences, Molecular processes, chemistry.chemical_compound, 0103 physical sciences, Radiative transfer, Emission spectrum, identification [Line], individual (IRC +10216) [Stars], 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, Astrochemistry, [PHYS]Physics [physics], Physics, Stars: AGB and post-AGB, Astronomy and Astrophysics, AGB and post-AGB [Stars], Circumstellar matter, Astrophysics - Astrophysics of Galaxies, Carbon star, 0104 chemical sciences, chemistry, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Excited state, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Phosphine
Abstract: Phosphine (PH3) was tentatively identified a few years ago in the carbon star envelopes IRC +10216 and CRL 2688 from observations of an emission line at 266.9 GHz attributable to the J = 1-0 rotational transition. We report the detection of the J = 2-1 rotational transition of PH3 in IRC +10216 using the HIFI instrument on board Herschel, which definitively confirms the identification of PH3. Radiative transfer calculations indicate that infrared pumping in excited vibrational states plays an important role in the excitation of PH3 in the envelope of IRC +10216, and that the observed lines are consistent with phosphine being formed anywhere between the star and 100 R* from the star, with an abundance of 10-8 relative to H2. The detection of PH3 challenges chemical models, none of which offer a satisfactory formation scenario. Although PH 3 holds just 2% of the total available phosphorus in IRC +10216, it is, together with HCP, one of the major gas phase carriers of phosphorus in the inner circumstellar layers, suggesting that it could also be an important phosphorus species in other astronomical environments. This is the first unambiguous detection of PH3 outside the solar system, and is a further step toward a better understanding of the chemistry of phosphorus in space., M.A. and J.C. thank Spanish MICINN for funding support through grant CSD2009-00038.
Published: 2014
Full Text: View/download PDF

49. An Optical Spectroscopic Study of T Tauri Stars. I. Photospheric Properties

Author: Lynne A. Hillenbrand, Gregory J. Herczeg, Kavli Institute for Astronomy and Astrophysics [Beijing] (KIAA-PKU), Peking University [Beijing], 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), Caltech Department of Astronomy [Pasadena], California Institute of Technology (CALTECH), and École normale supérieure - Paris (ENS Paris)
Subjects: Hertzsprung–Russell diagram, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Stellar classification, symbols.namesake, Binary star, Astrophysics::Solar and Stellar Astrophysics, ComputingMilieux_MISCELLANEOUS, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, Physics, [PHYS]Physics [physics], Photosphere, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Accretion (astrophysics), Stars, T Tauri star, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Extinction (optical mineralogy), Astrophysics of Galaxies (astro-ph.GA), symbols, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: Measurements of masses and ages of young stars from their location in the HR diagram are limited by not only the typical observational uncertainties that apply to field stars, but also by large systematic uncertainties related to circumstellar phenomena. In this paper, we analyze flux calibrated optical spectra to measure accurate spectral types and extinctions of 283 nearby T Tauri stars. The primary advances in this paper are (1) the incorporation of a simplistic accretion continuum in optical spectral type and extinction measurements calculated over the full optical wavelength range and (2) the uniform analysis of a large sample of stars. Comparisons between the non-accreting TTS photospheric templates and stellar photosphere models are used to derive conversions from spectral type to temperature. Differences between spectral types can be subtle and difficult to discern, especially when accounting for accretion and extinction. The spectral types measured here are mostly consistent with spectral types measured over the past decade. However, our new spectral types are 1-2 subclasses later than literature spectral types for the original members of the TWA and are discrepant with literature values for some well known Taurus CTTSs. Our extinction measurements are consistent with other optical extinction measurements but are typically 1 mag lower than nIR measurements, likely the result of methodological differences and the presence of nIR excesses in most CTTSs. As an illustration of the impact of accretion, SpT, and extinction uncertainties on the HR diagrams of young clusters, we find that the resulting luminosity spread of stars in the TWA is 15-30%. The luminosity spread in the TWA and previously measured for binary stars in Taurus suggests that for a majority of stars, protostellar accretion rates are not large enough to significantly alter the subsequent evolution., Comment: Accepted by ApJ. 30 pages plus 12 pages of Tables and References
Published: 2014
Full Text: View/download PDF

50. Filamentary Structure and Helical Magnetic Fields in the Environment of a Starless Dense Core

Author: Thomas G. Phillips, Jérôme Pety, Edith Falgarone, Laboratoire de Radioastronomie (LRA), Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), 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), Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), California Institute of Technology (CALTECH), École normale supérieure - Paris (ENS-PSL), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL)
Subjects: Physics, Range (particle radiation), Toroid, [SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], 010308 nuclear & particles physics, ISM: Clouds, Astronomy and Astrophysics, Astrophysics, ISM: Magnetic Fields -ISM: Molecules, 01 natural sciences, Instability, Magnetic field, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Transverse plane, Wavelength, Space and Planetary Science, 0103 physical sciences, Magnetohydrodynamic drive, 010303 astronomy & astrophysics, Line (formation)
Abstract: The environment of L1512, a starless dense core, has been mapped at high angular resolution in the ^(12)CO (J = 2-1) line over more than 1 pc, with a few positions observed in the ^(12)CO (J = 3-2) and (J = 4-3) lines. The gas outside the dense core is structured in several filaments, roughly 1 pc long and ~0.1 pc thick, converging at the dense core position. Small longitudinal (~1 km s^(-1) pc^(-1)) but large transverse (up to 8 km s^(-1) pc^(-1)) velocity gradients are observed. Remarkably, the transverse gradients can be seen to change sign periodically, along at least one of the filaments. Thus, there are oscillations in the toroidal velocity within the filaments, which may be a signature of a magnetohydrodynamic instability developing in filaments permeated by a helical magnetic field. In the case of L1512, according to the analysis of Fiege & Pudritz, the growth rate of the instability is low, corresponding to a timescale of the order of 1 Myr. We deduce from the wavelength of the oscillations that the toroidal component of the magnetic field dominates the poloidal component. The toroidal component helps confine the filaments, which are not otherwise confined by self-gravity (m/m_(vir) ~ 0.2), by the pressure of the galactic H I layer, or by external turbulent pressure. We find that the velocity gradients in the vicinity of the dense core provide an estimate for an upper limit to the accretion rate onto the dense core of Ṁ = 4 × 10-6 M_☉ yr^(-1). For the gas characteristics in the filaments, we find that a broad range of density and temperature is allowed for the gas, from n_(H(_2)) = 2 × 10^3 cm^(-3) for the coldest case (T_k = 20 K) down to n_(H(_2)) = 180 cm^(-3) for the warmest (T_k = 250 K).
Published: 2001
Full Text: View/download PDF

Catalog

Books, media, physical & digital resources

See catalog results

Searchworks

Select search scope, currently: Articles Catalog books, media & more in Jio Institute collections Articles journal articles & other e-resources

Search

Search Constraints

Refine your results

Search Limiters

Topic

Publication Year Range

Language

Journal

Database

90 results on '"Université de Cergy Pontoise (UCP)"'

Search Results

Catalog

Select search scope, currently: Articles

Catalog

books, media & more in Jio Institute collections

Articles

journal articles & other e-resources