Author: "Javier R. Goicoechea" - Searchworks@Jio Institute Digital Library Search Results

Your search keyword '"Javier R. Goicoechea"' showing total 154 results

Start Over Author "Javier R. Goicoechea"

154 results on '"Javier R. Goicoechea"'

1. The VLT MUSE NFM view of outflows and externally photoevaporating discs near the orion bar★

Author: Thomas J Haworth, Megan Reiter, C Robert O’Dell, Peter Zeidler, Olivier Berne, Carlo F Manara, Giulia Ballabio, Jinyoung S Kim, John Bally, Javier R Goicoechea, Mari-Liis Aru, Aashish Gupta, and Anna Miotello
Published: 2023
Full Text: View/download PDF

2. Mixture of noises and sampling of non-log-concave posterior distributions.

Author: Pierre Palud, Pierre Chainais, Franck Le Petit, Emeric Bron, Pierre-Antoine Thouvenin, Maxime Vono, L. Einig, M. Garcia Santa-Maria, Mathilde Gaudel, Jan H. Orkisz, Victor de Souza Magalhaes, Sébastien Bardeau, Maryvonne Gerin, Javier R. Goicoechea, Pierre Gratier, Viviana V. Guzmán, Jouni Kainulainen, François Levrier, Nicolas Peretto, Jérome Pety, Antoine Roueff, and Albrecht Sievers
Published: 2022

3. A Fully Bayesian Approach For Inferring Physical Properties With Credibility Intervals From Noisy Astronomical Data.

Author: Maxime Vono, Javier R. Goicoechea, Pierre Gratier, Viviana V. Guzmán, Annie Hughes, Jouni Kainulainen, David Languignon, Jacques Le Bourlot, François Levrier, Harvey S. Listz, Karin I. Oberg, Emeric Bron, Jan H. Orkisz, Nicolas Peretto, Jérome Pety, Antoine Roueff, èvelyne Roueff, Albrecht Sievers, Victor de Souza Magalhaes, Pascal Tremblin, Pierre Chainais, Franck Le Petit, Sébastien Bardeau, Sébastien Bourguignon, Jocelyn Chanussot, Mathilde Gaudel, and Maryvonne Gerin
Published: 2019
Full Text: View/download PDF

4. PDRs4All: A JWST Early Release Science Program on Radiative Feedback from Massive Stars

Author: Olivier Berné, Émilie Habart, Els Peeters, Alain Abergel, Edwin A. Bergin, Jeronimo Bernard-Salas, Emeric Bron, Jan Cami, Emmanuel Dartois, Asunción Fuente, Javier R. Goicoechea, Karl D. Gordon, Yoko Okada, Takashi Onaka, Massimo Robberto, Markus Röllig, Alexander G. G. M. Tielens, Sílvia Vicente, Mark G. Wolfire, Felipe Alarcón, C. Boersma, Amélie Canin, Ryan Chown, Daniel Dicken, David Languignon, Romane Le Gal, Marc W. Pound, Boris Trahin, Thomas Simmer, Ameek Sidhu, Dries Van De Putte, Sara Cuadrado, Claire Guilloteau, Alexandros Maragkoudakis, Bethany R. Schefter, Thiébaut Schirmer, Stéphanie Cazaux, Isabel Aleman, Louis Allamandola, Rebecca Auchettl, Giuseppe Antonio Baratta, Salma Bejaoui, Partha P. Bera, Goranka Bilalbegović, John H. Black, Francois Boulanger, Jordy Bouwman, Bernhard Brandl, Philippe Brechignac, Sandra Brünken, Andrew Burkhardt, Alessandra Candian, Jose Cernicharo, Marin Chabot, Shubhadip Chakraborty, Jason Champion, Sean W. J. Colgan, Ilsa R. Cooke, Audrey Coutens, Nick L. J. Cox, Karine Demyk, Jennifer Donovan Meyer, Cécile Engrand, Sacha Foschino, Pedro García-Lario, Lisseth Gavilan, Maryvonne Gerin, Marie Godard, Carl A. Gottlieb, Pierre Guillard, Antoine Gusdorf, Patrick Hartigan, Jinhua He, Eric Herbst, Liv Hornekaer, Cornelia Jäger, Eduardo Janot-Pacheco, Christine Joblin, Michael Kaufman, Francisca Kemper, Sarah Kendrew, Maria S. Kirsanova, Pamela Klaassen, Collin Knight, Sun Kwok, Álvaro Labiano, Thomas S.-Y. Lai, Timothy J. Lee, Bertrand Lefloch, Franck Le Petit, Aigen Li, Hendrik Linz, Cameron J. Mackie, Suzanne C. Madden, Joëlle Mascetti, Brett A. McGuire, Pablo Merino, Elisabetta R. Micelotta, Karl Misselt, Jon A. Morse, Giacomo Mulas, Naslim Neelamkodan, Ryou Ohsawa, Alain Omont, Roberta Paladini, Maria Elisabetta Palumbo, Amit Pathak, Yvonne J. Pendleton, Annemieke Petrignani, Thomas Pino, Elena Puga, Naseem Rangwala, Mathias Rapacioli, Alessandra Ricca, Julia Roman-Duval, Joseph Roser, Evelyne Roueff, Gaël Rouillé, Farid Salama, Dinalva A. Sales, Karin Sandstrom, Peter Sarre, Ella Sciamma-O’Brien, Kris Sellgren, Matthew J. Shannon, Sachindev S. Shenoy, David Teyssier, Richard D. Thomas, Aditya Togi, Laurent Verstraete, Adolf N. Witt, Alwyn Wootten, Nathalie Ysard, Henning Zettergren, Yong Zhang, Ziwei E. Zhang, Junfeng Zhen, Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Institut d'astrophysique spatiale (IAS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), University of Western Ontario (UWO), Carl Sagan Center, SETI Institute, University of Michigan [Ann Arbor], University of Michigan System, Analytic and Computational Research, Inc. - Earth Sciences (ACRI-ST), 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), École normale supérieure - Paris (ENS-PSL), 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), Institut des Sciences Moléculaires d'Orsay (ISMO), Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Observatorio Astronomico Nacional, Madrid, Instituto de Física Fundamental [Madrid] (IFF), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Universiteit Gent = Ghent University (UGENT), Space Telescope Science Institute (STSci), Physikalisches Institut [Köln], Universität zu Köln = University of Cologne, Meisei University, The University of Tokyo (UTokyo), Leiden Observatory [Leiden], Universiteit Leiden, Johns Hopkins University (JHU), Instituto de Astrofísica e Ciências do Espaço (IASTRO), University of Maryland [College Park], University of Maryland System, NASA Ames Research Center (ARC), Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France, Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), Signal et Communications (IRIT-SC), Institut de recherche en informatique de Toulouse (IRIT), Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT)-Université de Toulouse (UT)-Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Toulouse Mind & Brain Institut (TMBI), Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT), Institut National Polytechnique (Toulouse) (Toulouse INP), Onsala Space Observatory (OSO), Chalmers University of Technology [Göteborg], Delft University of Technology (TU Delft), Universidade Federal de Itajubá, Bay Area Environmental Research Institute (BAER), Australian Synchrotron [Clayton], INAF - Osservatorio Astrofisico di Catania (OACT), Istituto Nazionale di Astrofisica (INAF), University of Zagreb, Laboratoire de physique de l'ENS - ENS Paris (LPENS), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Département de Physique de l'ENS-PSL, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), University of Colorado [Boulder], Institute for Molecules and Materials [Nijmegen], Radboud University [Nijmegen], Wellesley College, Laboratoire de Physique des 2 Infinis Irène Joliot-Curie (IJCLab), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut de Physique de Rennes (IPR), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), University of British Columbia (UBC), National Radio Astronomy Observatory [Charlottesville] (NRAO), National Radio Astronomy Observatory (NRAO), European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA), Harvard-Smithsonian Center for Astrophysics (CfA), Harvard University-Smithsonian Institution, Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut Universitaire de France (IUF), Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.), Rice University [Houston], Yunnan Observatories, Chinese Academy of Sciences [Changchun Branch] (CAS), Universidad de Chile = University of Chile [Santiago] (UCHILE), University of Virginia, Aarhus University [Aarhus], Friedrich-Schiller-Universität = Friedrich Schiller University Jena [Jena, Germany], Instituto de Astronomia, Geofísica e Ciências Atmosféricas [São Paulo] (IAG), Universidade de São Paulo = University of São Paulo (USP), San Jose State University [San Jose] (SJSU), European Southern Observatory (ESO), Academia Sinica Institute of Astronomy and Astrophysics (ASIAA), Academia Sinica, Institute of Astronomy of the Russian Academy of Sciences (INASAN), Russian Academy of Sciences [Moscow] (RAS), UK Astronomy Technology Centre (UK ATC), Science and Technology Facilities Council (STFC), Telespazio, Services par satellites, Infrared Processing and Analysis Center (IPAC), California Institute of Technology (CALTECH), University of Missouri [Columbia] (Mizzou), University of Missouri System, Max Planck Institute for Astronomy (MPIA), CAS Key Laboratory of Crust–Mantle Materials and Environments [Hefei], School of Earth and Space Sciences [Hefei], University of Science and Technology of China [Hefei] (USTC)-University of Science and Technology of China [Hefei] (USTC)-Chinese Academy of Sciences [Beijing] (CAS), Lawrence Berkeley National Laboratory [Berkeley] (LBNL), University of California [Berkeley] (UC Berkeley), University of California (UC), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Institut des Sciences Moléculaires (ISM), Université Montesquieu - Bordeaux 4-Université Sciences et Technologies - Bordeaux 1 (UB)-École Nationale Supérieure de Chimie et de Physique de Bordeaux (ENSCPB)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Massachusetts Institute of Technology (MIT), Instituto de Ciencia de Materiales de Madrid (ICMM), Helsingin yliopisto = Helsingfors universitet = University of Helsinki, Steward Observatory, University of Arizona, INAF - Osservatorio Astronomico di Cagliari (OAC), United Arab Emirates University (UAEU), National Astronomical Observatory of Japan (NAOJ), Banaras Hindu University [Varanasi] (BHU), University of Amsterdam [Amsterdam] (UvA), Laboratoire de Chimie et Physique Quantiques Laboratoire (LCPQ), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Fédération de recherche « Matière et interactions » (FeRMI), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Universidade Federal do Rio Grande do Sul [Porto Alegre] (UFRGS), University of California [San Diego] (UC San Diego), University of Nottingham, UK (UON), Ohio State University [Columbus] (OSU), Space Science Institute [Boulder] (SSI), Stockholm University, Texas State University, Ritter Astrophysical Research Center, University of Toledo, National Sun Yat-Sen University (NSYSU), Star and Planet Formation Laboratory, ITA, USA, GBR, FRA, DEU, ESP, AUS, BEL, BRA, CHL, TWN, HRV, DNK, JPN, IND, NLD, PRT, CHN, RUS, SWE, National Aeronautics and Space Administration (US), University of Maryland, University of Michigan, Centre National de la Recherche Scientifique (France), Centre National D'Etudes Spatiales (France), Natural Sciences and Engineering Research Council of Canada, Ministerio de Ciencia e Innovación (España), German Research Foundation, Japan Society for the Promotion of Science, San José State University Research Foundation, Berné, Olivier, Habart, Émilie, Peeters, Els, Abergel, Alain, Bergin, Edwin A., Bernard-Salas, Jeronimo, Bron, Emeric, Cami, Jan, Dartois, Emmanuel, Fuente, Asunción, Goicoechea, Javier R., Gordon, Karl D., Okada, Yoko, Onaka, Takashi, Robberto, Massimo, Röllig, Markus, Tielens, Alexander G.G.M., Vicente, Sílvia, Wolfire, Mark G., Alarcón, Felipe, Boersma, C., Canin, Amélie, Chown, Ryan, Dicken, Daniel, Le Gal, Romane, Pound, Marc W., Trahin, Boris, Sidhu, Ameek, Van De Putte, Dries, Cuadrado, Sara, Guilloteau, Claire, Maragkoudakis, Alexandros, Schefter, Bethany R., Schirmer, Thiébaut, Aleman, Isabel, Allamandola, Louis, Auchettl, Rebecca, Antonio Baratta, Giuseppe, Bejaoui, Salma, Bera, Partha P., Bilalbegović, Goranka, Black, John H., Boulanger, Francois, Bouwman, Jordy, Brandl, Bernhard, Brünken, Sandra, Burkhardt, Andrew, Candian, Alessandra, Cernicharo, José, Chakraborty, Shubhadip, Champion, Jason, Colgan, Sean W.J., Cooke, Ilsa R., Coutens, Audrey, Cox, Nick L.J., Demyk, Karine, Donovan Meyer, Jennifer, Engrand, Cécile, Foschino, Sacha, Gavilan, Lisseth, Gerin, Maryvonne, Godard, Marie, Gottlieb, Carl A., Guillard, Pierre, Gusdorf, Antoine, Hartigan, Patrick, He, Jinhua, Herbst, Eric, Hornekaer, Liv, Janot-Pacheco, Eduardo, Joblin, Christine, Kaufman, Michael, Kemper, Francisca, Kendrew, Sarah, Kirsanova, Maria S., Klaassen, Pamela, Knight, Collin, Kwok, Sun, Labiano, Álvaro, Lai, Thomas S.Y., Lee, Timothy J., Lefloch, Bertrand, Le Petit, Franck, Li, Aigen, Linz, Hendrik, MacKie, Cameron J., Madden, Suzanne C., Mascetti, Joëlle, McGuire, Brett A., Merino, Pablo, Micelotta, Elisabetta R., Morse, Jon A., Molecular Spectroscopy (HIMS, FNWI), and HIMS (FNWI)
Subjects: Gaseous Nebulae, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, FELIX Infrared and Terahertz Spectroscopy, Star Forming Regions, Astrophysics - Astrophysics of Galaxies, Infrared Telescopes, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Astrophysics::Solar and Stellar Astrophysics, [INFO]Computer Science [cs], Photodissociation Regions, Astrophysics::Earth and Planetary Astrophysics, Polycyclic Aromatic Hydrocarbons, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], James Webb Space Telescope (JWST), Photo-Dissociation Regions (PDRs), Massive stars, Orion Bar, MIRI, NIRSpec, NIRCam, Astrophysics::Galaxy Astrophysics
Abstract: 22 pags., 8 figs., 1 tab., Massive stars disrupt their natal molecular cloud material through radiative and mechanical feedback processes. These processes have profound effects on the evolution of interstellar matter in our Galaxy and throughout the universe, from the era of vigorous star formation at redshifts of 1-3 to the present day. The dominant feedback processes can be probed by observations of the Photo-Dissociation Regions (PDRs) where the far-ultraviolet photons of massive stars create warm regions of gas and dust in the neutral atomic and molecular gas. PDR emission provides a unique tool to study in detail the physical and chemical processes that are relevant for most of the mass in inter-and circumstellar media including diffuse clouds, proto-planetary disks, and molecular cloud surfaces, globules, planetary nebulae, and star-forming regions. PDR emission dominates the infrared (IR) spectra of star-forming galaxies. Most of the Galactic and extragalactic observations obtained with the James Webb Space Telescope (JWST) will therefore arise in PDR emission. In this paper we present an Early Release Science program using the MIRI, NIRSpec, and NIRCam instruments dedicated to the observations of an emblematic and nearby PDR: the Orion Bar. These early JWST observations will provide template data sets designed to identify key PDR characteristics in JWST observations. These data will serve to benchmark PDR models and extend them into the JWST era. We also present the Science-Enabling products that we will provide to the community. These template data sets and Science-Enabling products will guide the preparation of future proposals on star-forming regions in our Galaxy and beyond and will facilitate data analysis and interpretation of forthcoming JWST observations., Support for JWST-ERS program ID 1288 was provided through grants from the STScI under NASA contract NAS5-03127 to STScI (K.G., D.V.D.P., M.R.), Univ. of Maryland (M.W., M.P.), Univ. of Michigan (E.B., F.A.), and Univ. of Toledo (T.S.-Y.L.). O.B. and E.H. are supported by the Programme National “Physique et Chimie du Milieu Interstellaire” (PCMI) of CNRS/INSU with INC/INP co-funded by CEA and CNES, and through APR grants 6315 and 6410 provided by CNES. E. P. and J.C. acknowledge support from the National Science and Engineering Council of Canada (NSERC) Discovery Grant program (RGPIN-2020-06434 and RGPIN-2021-04197 respectively). E.P. acknowledges support from a Western Strategic Support Accelerator Grant (ROLA ID 0000050636). J.R.G. and S.C. thank the Spanish MCINN for funding support under grant PID2019-106110GB-I00. Work by M.R. and Y.O. is carried out within the Collaborative Research Centre 956, subproject C1, funded by the Deutsche Forschungsgemeinschaft (DFG)—project ID 184018867. T.O. acknowledges support from JSPS Bilateral Program, grant No. 120219939. M.P. and M.W. acknowledge support from NASA Astrophysics Data Analysis Program award #80NSSC19K0573. C.B. is grateful for an appointment at NASA Ames Research Center through the San José State University Research Foundation (NNX17AJ88A) and acknowledges support from the Internal Scientist Funding Model (ISFM) Directed Work Package at NASA Ames titled: “Laboratory Astrophysics—The NASA Ames PAH IR Spectroscopic Database.”
Published: 2022
Full Text: View/download PDF

5. The role of highly vibrationally excited H2 initiating the N chemistry: Quantum study and 3-sigma detection of NH emission in the Orion Bar PDR

Author: Javier R. Goicoechea, Octavio Roncero, and Ministerio de Ciencia e Innovación (España)
Subjects: Photon-dominated region (PDR), Space and Planetary Science, Line: identification, Astrophysics of Galaxies (astro-ph.GA), FOS: Physical sciences, Astronomy and Astrophysics, Astro-ph.GA, Molecular processes, Astrophysics - Astrophysics of Galaxies, ISM: molecules
Abstract: 14 pags., 11 figs., 5 tabs., The formation of hydrides by gas-phase reactions between H2 and a heavy element atom is a very selective process. Reactions with ground-state neutral carbon, oxygen, nitrogen, and sulfur atoms are very endoergic and have high energy barriers because the H2 molecule has to be fragmented before a hydride bond is formed. In cold interstellar clouds, these barriers exclude the formation of CH, OH, NH, and SH radicals through hydrogen abstraction reactions. Here we study a very energetically unfavorable process, the reaction of N(4S) atoms with H2 molecules. We calculated the reaction rate coefficient for H2 in different vibrational levels, using quantum methods for v=0-7 and quasi-classical methods up to v=12. Owing to the high energy barrier, these rate coefficients increase with v and also with the gas temperature. We implemented the new rates in the Meudon PDR code and studied their effect on models with different ultraviolet (UV) illumination conditions. In strongly UV-irradiated dense gas (Orion Bar conditions), the presence of H2 in highly vibrationally excited levels (v>7) enhances the NH abundance by two orders of magnitude (at the PDR surface) compared to models that use the thermal rate coefficient for reaction N(4S) + H2 -> NH + H. The increase in NH column density across the PDR is a factor of ~25. We explore existing Herschel/HIFI observations of the Orion Bar and Horsehead PDRs. We report a 3-sigma emission feature at the ~974 GHz frequency of the NH N_J=1_2-0_1 line toward the Bar. The emission level implies N(NH)~10^13 cm^-2, which is consistent with PDR models using the new rate coefficients for reactions between N and UV-pumped H2. This formation route dominates over hydrogenation reactions involving the less abundant N+ ion. JWST observations will soon quantify the amount and reactivity of UV-pumped H2 in many interstellar and circumstellar environments., We thank the Spanish MCINN for funding support under grants PID2019-106110GB-I00 and PID2021-122549NB-C21.
Published: 2022

6. High angular resolution near-IR view of the Orion Bar revealed by Keck/NIRC2

Author: Emilie Habart, Romane Le Gal, Carlos Alvarez, Els Peeters, Olivier Berné, Mark G. Wolfire, Javier R. Goicoechea, Thiébaut Schirmer, Emeric Bron, and Markus Röllig
Subjects: Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Solar and Stellar Astrophysics (astro-ph.SR)
Abstract: Context. Nearby photo-dissociation regions (PDRs), where the gas and dust are heated by the far-ultraviolet (FUV) irradiation emitted from stars, are ideal templates with which to study the main stellar feedback processes. Aims. With this study, we aim to probe the detailed structures at the interfaces between ionized, atomic, and molecular gas in the Orion Bar. This nearby prototypical strongly irradiated PDR are among the first targets of the James Webb Space Telescope (JWST) within the framework of the PDRs4All Early Release Science program. Methods. We employed the subarcsecond resolution accessible with Keck-II NIRC2 and its adaptive optics system to obtain images of the vibrationally excited line H2 1−0 S(1) at 2.12 µm that are more detailed and complete than ever before. H2 1−0 S(1) traces the dissociation front (DF), and the [FeII] and Brγ lines, at 1.64 and 2.16 µm, respectively, trace the ionization front (IF). The former is a powerful tracer of the FUV radiation field strength and gas density distribution at the PDR edge, while the last two trace the temperature and density distribution from the ionized gas to the PDR. We obtained narrow-band filter images in these key gas line diagnostics over ~40″ at spatial scales of ~0.1″ (~0.0002 pc or ~40 AU at 414 pc). Results. The Keck/Near Infrared Camera 2 (NIRC2) observations spatially resolve a plethora of irradiated substructures such as ridges, filaments, globules, and proplyds. This portends what JWST should accomplish and how it will complement the highest resolution Atacama Large Millimeter/submillimeter Array (ALMA) maps of the molecular cloud. We observe a remarkable spatial coincidence between the H2 1−0 S(1) vibrational and HCO+ J = 4−3 rotational emission previously obtained with ALMA. This likely indicates the intimate link between these two molecular species and highlights that in high-pressure PDRs, the H/H2 and C+/C/CO transitions zones come closer than in a typical layered structure of a constant density PDR. The H/H2 dissociation front appears as a highly structured region containing substructures with a typical thickness of a few ~10−3 pc.
Published: 2022

7. Anomalous HCN emission from warm giant molecular clouds

Author: François Lique, M. G. Santa-Maria, Javier R. Goicoechea, Ministerio de Ciencia e Innovación (España), Spanish National Research Council (CSIC), Instituto de Física Fundamental [Madrid] (IFF), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institut de Physique de Rennes (IPR), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), and Spanish MCINN Spanish Government [PID2019-106110GB-I00]
Subjects: FOS: Physical sciences, Astrophysics, Molecular physics, ISM: clouds, Molecular processes, Radiative transfer, Astrophysics::Solar and Stellar Astrophysics, Hyperfine structure, Astrophysics::Galaxy Astrophysics, Line (formation), [PHYS]Physics [physics], Physics, Star formation, Molecular data, Molecular cloud, Astronomy and Astrophysics, Line: formation, Astrophysics - Astrophysics of Galaxies, Space and Planetary Science, Electron excitation, formation [Line], Astrophysics of Galaxies (astro-ph.GA), Excited state, Astrophysics::Earth and Planetary Astrophysics, clouds [ISM], Excitation
Abstract: 17 pags., 16 figs., 2 tabs., 3 apps., Hydrogen cyanide (HCN) is considered a good tracer of the dense molecular gas that serves as fuel for star formation. However, recent large-scale surveys of giant molecular clouds (GMCs) have detected extended HCN rotational line emission far from star-forming cores. Such observations often spectroscopically resolve the HCN J = 1-0 (partially also the J = 2-1 and 3-2) hyperfine structure (HFS). A precise determination of the physical conditions of the gas requires treating the HFS line overlap effects. Here, we study the HCN HFS excitation and line emission using nonlocal radiative transfer models that include line overlaps and new HFS-resolved collisional rate coefficients for inelastic collisions of HCN with both para-H2 and ortho-H2 (computed via the scaled-infinite order sudden approximation up to Tk = 500 K). In addition, we account for the role of electron collisions in the HFS level excitation. We find that line overlap and opacity effects frequently produce anomalous HCN J = 1-0 HFS line intensity ratios (i.e., inconsistent with the common assumption of the same Tex for all HFS lines) as well as anomalous HFS line width ratios. Line overlap and electron collisions also enhance the excitation of the higher J rotational lines. Our models explain the anomalous HCN J = 1-0 HFS spectra observed in the Orion Bar and Horsehead photodissociation regions. As shown in previous studies, electron excitation becomes important for molecular gas with H2 densities below a few 105 cm-3 and electron abundances above ∼10-5. We find that when electron collisions are dominant, the relative intensities of the HCN J = 1-0 HFS lines can be anomalous too. In particular, electron excitation can produce low-surface-brightness HCN emission from very extended but low-density gas in GMCs. The existence of such a widespread HCN emission component may affect the interpretation of the extragalactic relationship HCN luminosity versus star-formation rate. Alternatively, extended HCN emission may arise from dense star-forming cores and become resonantly scattered by large envelopes of lower density gas. There are two scenarios-namely, electron-assisted (weakly) collisionally excited versus scattering-that lead to different HCN J = 1-0 HFS intensity ratios, which can be tested on the basis of observations., We thank A. Faure for sharing his HCN-HFS + e rate coefficients in tabulated form. We warmly thank S. Cuadrado, J. Pety, and M. Gerin for providing the HCN J = 1–0 spectra of the Orion Bar and Horsehead, and for useful discussion on the HCN J = 1–0 HFS emission in Orion B. We thank our referee for concise and illuminating comments. J.R.G. and M.G.S.M. thank the Spanish MCINN for funding support under grant PID2019-106110GB-I00.
Published: 2022
Full Text: View/download PDF

8. Gas kinematics around filamentary structures in the Orion B cloud

Author: Mathilde Gaudel, Jan H. Orkisz, Maryvonne Gerin, Jérôme Pety, Antoine Roueff, Antoine Marchal, François Levrier, Marc-Antoine Miville-Deschênes, Javier R. Goicoechea, Evelyne Roueff, Franck Le Petit, Victor de Souza Magalhaes, Pierre Palud, Miriam G. Santa-Maria, Maxime Vono, Sébastien Bardeau, Emeric Bron, Pierre Chainais, Jocelyn Chanussot, Pierre Gratier, Viviana Guzman, Annie Hughes, Jouni Kainulainen, David Languignon, Jacques Le Bourlot, Harvey Liszt, Karin Öberg, Nicolas Peretto, Albrecht Sievers, Pascal Tremblin, Agence Nationale de la Recherche (France), Centre National de la Recherche Scientifique (France), Centre National D'Etudes Spatiales (France), l'Observatoire de Paris, Ministerio de Ciencia, Innovación y Universidades (España), Swedish Research Council, Orkisz, Jan H., Pety, Jérôme, Roueff, Antoine, Marchal, Antoine, Levrier, François, Miville-Deschênes, Marc-Antoine, Goicoechea, Javier R., Roueff, Evelyne, Santa-Maria, Miriam G., Bron, Emeric, Chainais, Pierre, Chanussot, Jocelyn, Gratier, Pierre, Guzman, Viviana, Le Bourlot,Jacques, and Liszt, Harvey
Subjects: ISM: kinematics and dynamics, HII regions, ISM: individual objects: Orion B, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Stars: formation, FOS: Physical sciences, Astronomy and Astrophysics, ISM: clouds, Astrophysics - Astrophysics of Galaxies, Radio lines: ISM
Abstract: 39 pags., 78 figs., 2 tabs. 6 apps., Understanding the initial properties of star-forming material and how they affect the star formation process is key. From an observational point of view, the feedback from young high-mass stars on future star formation properties is still poorly constrained. In the framework of the IRAM 30m ORION-B large program, we obtained observations of the translucent and moderately dense gas, which we used to analyze the kinematics over a field of 5 deg^2 around the filamentary structures. We used the ROHSA algorithm to decompose and de-noise the C18O(1-0) and 13CO(1-0) signals by taking the spatial coherence of the emission into account. We produced gas column density and mean velocity maps to estimate the relative orientation of their spatial gradients. We identified three cloud velocity layers at different systemic velocities and extracted the filaments in each velocity layer. The filaments are preferentially located in regions of low centroid velocity gradients. By comparing the relative orientation between the column density and velocity gradients of each layer from the ORION-B observations and synthetic observations from 3D kinematic toy models, we distinguish two types of behavior in the dynamics around filaments: (i) radial flows perpendicular to the filament axis that can be either inflows (increasing the filament mass) or outflows and (ii) longitudinal flows along the filament axis. The former case is seen in the Orion B data, while the latter is not identified. We have also identified asymmetrical flow patterns, usually associated with filaments located at the edge of an HII region. This is the first observational study to highlight feedback from HII regions on filament formation and, thus, on star formation in the Orion B cloud. This simple statistical method can be used for any molecular cloud to obtain coherent information on the kinematics., This work was supported in part by the French Agence Nationale de la Recherche through the DAOISM grant ANR21-CE31-0010 and by the Programme National “Physique et Chimie du Milieu Interstellaire” (PCMI) of CNRS/INSU with INC/INP, co-funded by CEA and CNES. We thank “le centre Jules Jensen” from Observatoire de Paris for its hospitality during the workshops devoted to this project. This research has made use of data from the Herschel Gould Belt Survey (HGBS) project (http: //gouldbelt-herschel.cea.fr). The HGBS is a Herschel Key Programme jointly carried out by SPIRE Specialist Astronomy Group 3 (SAG 3), scientists of several institutes in the PACS Consortium (CEA Saclay, INAF-IFSI Rome and INAF-Arcetri, KU Leuven, MPIA Heidelberg), and scientists of the Herschel Science Center (HSC). J.R.G. and M.G.S.M. thank the Spanish MCIYU for funding support under grant PID2019-106110GB-I00. J.O. acknowledges funding from the Swedish Research Council, grant No. 2017-03864.
Published: 2023
Full Text: View/download PDF

9. Importance of radiative pumping for the excitation of the H2O submillimeter lines in galaxies

Author: Eduardo González-Alfonso, Jacqueline Fischer, Javier R. Goicoechea, Chentao Yang, Miguel Pereira-Santaella, and Kenneth P. Stewart
Subjects: Space and Planetary Science, Astronomy and Astrophysics
Abstract: H2O submillimeter emission is a powerful diagnostic of the molecular interstellar medium in a variety of sources, including low- and high-mass star-forming regions of the Milky Way, and from local to high-redshift galaxies. However, the excitation mechanism of these lines in galaxies has been debated, preventing a basic consensus on the physical information that H2O provides. Radiative pumping due to H2O absorption of far-infrared photons emitted by dust and collisional excitation in dense shocked gas have both been proposed to explain the H2O emission. Here we propose two basic diagnostics to distinguish between the two mechanisms: First, the ortho-H2O 321 − 212 75 μm and the para-H2O 220 − 111 101 μm rotational lines in shock-excited regions are expected to be in emission, while when radiative pumping dominates, the two far-infrared lines are expected to be in absorption. Second, the radiative pumping scenario predicts, based on the statistical equilibrium of H2O level populations, that the apparent isotropic net rate of far-infrared absorption in the 321 ← 212 (75 μm) and 220 ← 111 (101 μm) lines should be higher than or equal to the apparent isotropic net rate of submillimeter emission in the 321 → 312 (1163 GHz) and 220 → 211 (1229 GHz) lines, respectively. Applying both criteria to all 16 galaxies and several Galactic high-mass star-forming regions in which the H2O 75 μm and submillimeter lines have been observed with Herschel/PACS and SPIRE, we show that in most (extra)galactic sources, the H2O submillimeter line excitation is dominated by far-infrared pumping, combined in some cases with collisional excitation of the lowest energy levels. Based on this finding, we revisit the interpretation of the correlation between the luminosity of the H2O 988 GHz line and the source luminosity in the combined Galactic and extragalactic sample.
Published: 2022
Full Text: View/download PDF

10. Observation and calibration strategies for large-scale multi-beam velocity-resolved mapping of the [CII] emission in the Orion molecular cloud

Author: Rolf Güsten, S. Suri, Olivier Berné, S. Kabanovic, Mark G. Wolfire, Alexander G. G. M. Tielens, C. H. M. Pabst, Ronan Higgins, Javier R. Goicoechea, Yoko Okada, Heiko Richter, A. Parikka, Juergen Stutzki, E. Chambers, D. Teyssier, Christof Buchbender, M. Mertens, Rebeca Aladro, National Aeronautics and Space Administration (US), Universities Space Research Association (US), University of Stuttgart, German Research Foundation, Ministerio de Ciencia, Innovación y Universidades (España), Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)
Subjects: Heterodyne, ISM: individual (Orion), Instrumentation: spectrometer, ISM: structure, Local insterstellar matter, FOS: Physical sciences, Context (language use), Instrumentation: spectrographs, Astrophysics, Methods: observational, ISM: photon-dominated region (PDR), Radiative transfer, observational [Methods], Spectral resolution, spectrographs [Instrumentation], Submillimeter: ISM, Instrumentation and Methods for Astrophysics (astro-ph.IM), Physics, ISM: kinematics and dynamics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Stratospheric Observatory for Infrared Astronomy, Molecular cloud, ISM [Submillimeter], Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Interstellar medium, kinematics and dynamics [ISM], Far-infrared: ISM, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Astrophysics of Galaxies (astro-ph.GA), ISM: bubbles, Photon-dominated region, Astrophysics - Instrumentation and Methods for Astrophysics, Data reduction
Abstract: 24 pags., 32 figs., 3 tabs., Context. The [CII] 158 μm far-infrared fine-structure line is one of the dominant cooling lines of the star-forming interstellar medium. Hence [CII] emission originates in and thus can be used to trace a range of ISM processes. Velocity-resolved large-scale mapping of [CII] in star-forming regions provides a unique perspective of the kinematics of these regions and their interactions with the exciting source of radiation. Aims. We explore the scientific applications of large-scale mapping of velocity-resolved [CII] observations. With the [CII] observations, we investigate the effect of stellar feedback on the ISM. We present the details of observation, calibration, and data reduction using a heterodyne array receiver mounted on an airborne observatory. Methods. A 1.15 square degree velocity-resolved map of the Orion molecular cloud centred on the bar region was observed using the German REceiver for Astronomy at Terahertz Frequencies (upGREAT) heterodyne receiver flying on board the Stratospheric Observatory for Infrared Astronomy. The data were acquired using the 14 pixels of the German REceiver for Astronomy at Terahertz Frequencies that were observed in an on-the-fly mapping mode. 2.4 million spectra were taken in total. These spectra were gridded into a three-dimensional cube with a spatial resolution of 14.1 arcseconds and a spectral resolution of 0.3 km s-1. Results. A square-degree [CII] map with a spectral resolution of 0.3 km s-1 is presented. The scientific potential of this data is summarized with discussion of mechanical and radiative stellar feedback, filament tracing using [CII], [CII] opacity effects, [CII] and carbon recombination lines, and [CII] interaction with the large molecular cloud. The data quality and calibration is discussed in detail, and new techniques are presented to mitigate the effects of unavoidable instrument deficiencies (e.g. baseline stability) and thus to improve the data quality. A comparison with a smaller [CII] map taken with the Herschel/Heterodyne Instrument for the Far-Infrared spectrometer is presented. Conclusions. Large-scale [CII] mapping provides new insight into the kinematics of the ISM. The interaction between massive stars and the ISM is probed through [CII] observations. Spectrally resolving the [CII] emission is necessary to probe the microphysics induced by the feedback of massive stars. We show that certain heterodyne instrument data quality issues can be resolved using a spline-based technique, and better data correction routines allow for more efficient observing strategies., This work is based 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. This work is carried out within the Collaborative Research Centre 956, subproject [A4], funded by the Deutsche Forschungsgemeinschaft (DFG) – project ID 184018867. We thank the Spanish MICIU for funding support under grant AYA2017-85111-P.
Published: 2021
Full Text: View/download PDF

11. Gas phase Elemental abundances in Molecular cloudS (GEMS). IV. Observational results and statistical trends

Author: R. Le Gal, Izaskun Jiménez-Serra, Nuria Marcelino, Jaime E. Pineda, G. B. Esplugues, S. P. Treviño-Morales, Carsten Kramer, Maryvonne Gerin, G. Muñoz-Caro, Javier R. Goicoechea, Silvia Spezzano, Santiago García-Burillo, M. Rodríguez-Baras, Rafael Bachiller, D. Navarro-Almaida, Stéphanie Cazaux, Barbara M. Giuliano, Asunción Fuente, Benoît Commerçon, Rachel Friesen, Belén Tercero, Pablo Riviere-Marichalar, Octavio Roncero, Rafael Martín-Doménech, Valerio Lattanzi, Evelyne Roueff, M. Tafalla, Alvaro Hacar, Jean-Christophe Loison, Derek Ward-Thompson, T. Alonso-Albi, Paola Caselli, Johanna Malinen, Valentine Wakelam, Jason M. Kirk, Jacob C. Laas, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), 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)-CY Cergy Paris Université (CY), 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), Ministerio de Economía y Competitividad (España), Ministerio de Ciencia, Innovación y Universidades (España), European Commission, and Department of Physics
Subjects: Mean kinetic temperature, Abundances [ISM], FOS: Physical sciences, Astrophysics, F500, 01 natural sciences, ISM: clouds, ISM: abundances, Clouds [ISM], Abundance (ecology), TheoryofComputation_ANALYSISOFALGORITHMSANDPROBLEMCOMPLEXITY, Ionization, ISM [Galaxies], 0103 physical sciences, Protostar, Molecule, 010303 astronomy & astrophysics, formation [Stars], Astrochemistry, Physics, stars: formation, Molecules [ISM], 010308 nuclear & particles physics, Star formation, astrochemistry, Molecular cloud, F510, Astronomy and Astrophysics, 115 Astronomy, Space science, Astrophysics - Astrophysics of Galaxies, Galaxy, ISM: molecules, 3. Good health, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Astrophysics of Galaxies (astro-ph.GA), galaxies: ISM
Abstract: 28 pags., 22 figs., 4 tabs., Gas phase Elemental abundances in Molecular CloudS (GEMS) is an IRAM 30 m Large Program designed to provide estimates of the S, C, N, and O depletions and gas ionization degree, X(e−), in a selected set of star-forming filaments of Taurus, Perseus, and Orion. Our immediate goal is to build up a complete and large database of molecular abundances that can serve as an observational basis for estimating X(e−) and the C, O, N, and S depletions through chemical modeling. We observed and derived the abundances of 14 species (13CO, C18O, HCO+, H13CO+, HC18O+, HCN, H13CN, HNC, HCS+, CS, SO, 34SO, H2S, and OCS) in 244 positions, covering the AV ~3 to ~100 mag, n(H2) ~ a few 103 to 106 cm−3, and Tk ~10 to ~30 K ranges in these clouds, and avoiding protostars, HII regions, and bipolar outflows. A statistical analysis is carried out in order to identify general trends between different species and with physical parameters. Relations between molecules reveal strong linear correlations which define three different families of species: (1) 13CO and C18O isotopologs; (2) H13CO+, HC18O+, H13 CN, and HNC; and (3) the S-bearing molecules. The abundances of the CO isotopologs increase with the gas kinetic temperature until TK ~ 15 K. For higher temperatures, the abundance remains constant with a scatter of a factor of ~3. The abundances of H13 CO+, HC18 O+, H13 CN, and HNC are well correlated with each other, and all of them decrease with molecular hydrogen density, following the law ∝ n(H2)−0.8 ± 0.2. The abundances of S-bearing species also decrease with molecular hydrogen density at a rate of (S-bearing/H)gas ∝ n(H2)−0.6 ± 0.1. The abundances of molecules belonging to groups 2 and 3 do not present any clear trend with gas temperature. At scales of molecular clouds, the C18O abundance is the quantity that better correlates with the cloud mass. We discuss the utility of the 13CO/C18O, HCO+/H13CO+, and H13 CO+/H13CN abundance ratios as chemical diagnostics of star formation in external galaxies., We thank the Spanish the Spanish Ministerio de Ciencia e Innovación for funding support through AYA2016-75066-C2-1/2-P and PID2019-106235GB-I00. SG-B acknowledges support through grants PGC2018-094671-B-I00 (MICIU/AEI/FEDER,UE) and PID2019-106027GAC44. JRG acknowledges support through grants AYA2017-85111-P and PID2019-106110GB-I00. I.J.-S. has received partial support from the Spanish FEDER (project number ESP2017-86582-C4-1-R) and the State Research Agency (AEI; project number PID2019-105552RB-C41). SPTM acknowledges to the European Union’s Horizon 2020 research and innovation program for funding support given under grant agreement No 639459 (PROMISE).
Published: 2021
Full Text: View/download PDF

12. Bottlenecks to interstellar sulfur chemistry: Sulfur-bearing hydrides in UV-illuminated gas and grains

Author: Cinthya N. Herrera, S. Cuadrado, C. Duran, Denise Riquelme, Octavio Roncero, Edwige Chapillon, Emeric Bron, Jérôme Pety, Javier R. Goicoechea, Alfredo Aguado, Asunción Fuente, Ministerio de Ciencia, Innovación y Universidades (España), Ministerio de Economía y Competitividad (España), Centro de Supercomputación de Galicia, UAM.Departamento de Química Física Aplicada, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Observatoire de Paris, and 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)-CY Cergy Paris Université (CY)
Subjects: Line: identification, (ISM:) photon-dominated region (PDR), Binding energy, Analytical chemistry, Ab initio, FOS: Physical sciences, Astrophysics, 010402 general chemistry, Hydrogen atom abstraction, ISM: clouds, 01 natural sciences, 7. Clean energy, Dissociation (chemistry), 0103 physical sciences, Molecule, identification [Line], 010303 astronomy & astrophysics, Astrochemistry, [PHYS]Physics [physics], Hydride, Chemistry, ) photon-dominated region (PDR) [(ISM], Molecular cloud, Física, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, 0104 chemical sciences, 3. Good health, Astronomía, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Excited state, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Photon-dominated region, clouds [ISM]
Abstract: 25 pags., 24 figs., 9 tabs., Hydride molecules lie at the base of interstellar chemistry, but the synthesis of sulfuretted hydrides is poorly understood and their abundances often crudely constrained. Motivated by new observations of the Orion Bar photodissociation region (PDR) - 100 resolution ALMA images of SH+; IRAM 30 m detections of bright H32 2 S, H34 2 S, and H33 2 S lines; H3S+ (upper limits); and SOFIA/GREAT observations of SH (upper limits) we perform a systematic study of the chemistry of sulfur-bearing hydrides. We self-consistently determine their column densities using coupled excitation, radiative transfer as well as chemical formation and destruction models. We revise some of the key gas-phase reactions that lead to their chemical synthesis. This includes ab initio quantum calculations of the vibrational-state-dependent reactions SH+ + H2(v) H2S+ + H and S + H2 (v) SH + H.We find that reactions of UV-pumped H2(v 2) molecules with S+ ions explain the presence of SH+ in a high thermal-pressure gas component, Pth=k 108 cm-3 K, close to the H2 dissociation front (at AV < 2 mag). These PDR layers are characterized by no or very little depletion of elemental sulfur from the gas. However, subsequent hydrogen abstraction reactions of SH+, H2S+, and S atoms with vibrationally excited H2, fail to form enough H2S+, H3S+, and SH to ultimately explain the observed H2S column density (∼2.5 1014 cm-2, with an ortho-to-para ratio of 2.9 .3; consistent with the high-temperature statistical value). To overcome these bottlenecks, we build PDR models that include a simple network of grain surface reactions leading to the formation of solid H2S (s-H2S). The higher adsorption binding energies of S and SH suggested by recent studies imply that S atoms adsorb on grains (and form s-H2S) at warmer dust temperatures (Td < 50 K) and closer to the UV-illuminated edges of molecular clouds. We show that everywhere s-H2S mantles form(ed), gas-phase H2S emission lines will be detectable. Photodesorption and, to a lesser extent, chemical desorption, produce roughly the same H2S column density (a few 1014 cm-2) and abundance peak (a few 10-8) nearly independently of nH and G0. This agrees with the observed H2S column density in the Orion Bar as well as at the edges of dark clouds without invoking substantial depletion of elemental sulfur abundances., We thank the Spanish MICIU for funding support under grants AYA2016-75066-C2-2-P, AYA2017-85111-P, FIS2017-83473-C2 PID2019-106110GB-I00, and PID2019-106235GB-I00 and the French-Spanish collaborative project PICS (PIC2017FR). We finally acknowledge computing time at Finisterrae (CESGA) under RES grant ACCT-2019-3-0004.
Published: 2021
Full Text: View/download PDF

13. The initial gas-phase sulfur abundance in the Orion Molecular Cloud from sulfur radio recombination lines

Author: S. Cuadrado, Javier R. Goicoechea, Ministerio de Economía y Competitividad (España), and Ministerio de Ciencia, Innovación y Universidades (España)
Subjects: Line: identification, Interstellar cloud, chemistry.chemical_element, FOS: Physical sciences, Astrophysics, Photodissociation region, 01 natural sciences, ISM: abundances, Planet, 0103 physical sciences, identification [Line], 010303 astronomy & astrophysics, Radio lines: ISM, Line (formation), abundances [ISM], Physics, 010308 nuclear & particles physics, Molecular cloud, Astronomy and Astrophysics, Sulfur, Astrophysics - Astrophysics of Galaxies, ISM [Radio lines], Delta-v (physics), Stars, chemistry, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Photon-dominated region
Abstract: 8 pags., 5 figs., 2 tabs., The abundances of chemical elements and their depletion factors are essential parameters for understanding the composition of the gas and dust that are ultimately incorporated into stars and planets. Sulfur is an abundant but peculiar element in the sense that, despite being less volatile than other elements (e.g., carbon), it is not a major constituent of dust grains in diffuse interstellar clouds. Here, we determine the gas-phase carbon-to-sulfur abundance ratio, [C]/[S], and the [S] in a dense star-forming cloud from new radio recombination lines (RRLs) detected with the Yebes 40m telescope-at relatively high frequencies (∼40 GHz ∼7 mm) and angular resolutions (down to 36″)-in the Orion Bar, a rim of the Orion Molecular Cloud (OMC). We detect nine Cnα RRLs (with n = 51-59) as well as nine narrow line features separated from the Cnα lines by δv =-8.4 ± 0.3 km s-1. Based on this velocity separation, we assign these features to sulfur RRLs, with little contribution of RRLs from the more condensable elements Mg, Si, or Fe. Sulfur RRLs lines trace the photodissociation region of the OMC. In these neutral gas layers, up to AV ∼4, the ions C+ and S+ lock in most of the C and S gas-phase reservoir. We determine a relative abundance of [C]Ori/[S]Ori = 10.4 ± 0.6 and, adopting the same [C]Ori measured in the translucent gas toward star θ1 Ori B, an absolute abundance of [S]Ori = (1.4 ± 0.4) 10-5. This value is consistent with emission models of the observed sulfur RRLs if N(S+) ∼7 1017 cm-2 (beam-averaged). The [S]Ori is the "initial"sulfur abundance in the OMC, before an undetermined fraction of the [S]Ori goes into molecules and ice mantles in the cloud interior. The inferred abundance [S]Ori matches the solar abundance, thus implying that there is little depletion of sulfur onto rocky dust grains, with D(S) = 0.0 ± 0.2 dex., We thank the Spanish MCIYU for funding support under grants PID2019-106110GB-I00 and AYA2016-75066-C2-1-P.
Published: 2021
Full Text: View/download PDF

14. Submillimeter imaging of the Galactic Center starburst Sgr B2: Warm molecular, atomic, and ionized gas far from massive star-forming cores

Author: S. Cuadrado, M. Etxaluze, José Cernicharo, Javier R. Goicoechea, M. G. Santa-Maria, and Ministerio de Ciencia, Innovación y Universidades (España)
Subjects: 010504 meteorology & atmospheric sciences, ISM [Infrared], FOS: Physical sciences, Astrophysics, Star (graph theory), 01 natural sciences, Luminosity, law.invention, Telescope, law, Ionization, 0103 physical sciences, 010303 astronomy & astrophysics, Dust, extinction, 0105 earth and related environmental sciences, Luminous infrared galaxy, Physics, Infrared: ISM, Galaxy: center, Galactic Center, Astronomy and Astrophysics, Plasma, center [Galaxy], Astrophysics - Astrophysics of Galaxies, Galaxy, ISM: lines and bands, individual (Sagittarius B2) [ISM], Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), ISM: individual (Sagittarius B2), lines and bands [ISM]
Abstract: 28 pags., 21 figs., 9 tabs. -- This paper is dedicated to the memory of Bruce Swinyard, for his mentorship and his major contributions to the SPIRE-FTS performance and calibration., Context. Star-forming galaxies emit bright molecular and atomic lines in the submillimeter and far-infrared (FIR) domains. However, it is not always clear which gas heating mechanisms dominate and which feedback processes drive their excitation. Aims. The Sgr B2 complex is an excellent template to spatially resolve the main OB-type star-forming cores from the extended cloud environment and to study the properties of the warm molecular gas in conditions likely prevailing in distant extragalactic nuclei. Methods. We present 168 arcminspectral images of Sgr B2 taken with Herschel/SPIRE-FTS in the complete ∼450-1545 GHz band. We detect ubiquitous emission from mid-J CO (up to J = 12-11), HO 2-2, [C I] 492, 809 GHz, and [N II] 205 μm lines. We also present velocity-resolved maps of the SiO (2-1), NH, HCN, and HCO(1-0) emission obtained with the IRAM 30 m telescope. Results. The cloud environment (∼1000 pcaround the main cores) dominates the emitted FIR (∼80%), HO 752 GHz (∼60%) mid-J CO (∼91%), [C I] (∼93%), and [N II] 205 μm (∼95%) luminosity. The region shows very extended [N II] 205 μm emission (spatially correlated with the 24 and 70 μm dust emission) that traces an extended component of diffuse ionized gas of low ionization parameter (U 10) and low L/M4-11 LMratios (scaling as ≈ T). The observed FIR luminosities imply a flux of nonionizing photons equivalent to G≈ 10. All these diagnostics suggest that the complex is clumpy and this allows UV photons from young massive stars to escape from their natal molecular cores. The extended [C I] emission arises from a pervasive component of neutral gas with n≃ 10cm. The high ionization rates in the region, produced by enhanced cosmic-ray (CR) fluxes, drive the gas heating in this component to T≃ 40-60 K. The mid-J CO emission arises from a similarly extended but more pressurized gas component (P/≃ 10K cm): Spatially unresolved clumps, thin sheets, or filaments of UV-illuminated compressed gas (n≃ 10cm). Specific regions of enhanced SiO emission and high CO-to-FIR intensity ratios (I/I≃ 10) show mid-J CO emission compatible with C-type shock models. A major difference compared to more quiescent star-forming clouds in the disk of our Galaxy is the extended nature of the SiO and NHemission in Sgr B2. This can be explained by the presence of cloud-scale shocks, induced by cloud-cloud collisions and stellar feedback, and the much higher CR ionization rate (>10s) leading to overabundant Hand NH. Conclusions. Sgr B2 hosts a more extreme environment than star-forming regions in the disk of the Galaxy. As a usual template for extragalactic comparisons, Sgr B2 shows more similarities to nearby ultra luminous infrared galaxies such as Arp 220, including a "deficit" in the [C I]/FIR and [N II]/FIR intensity ratios, than to pure starburst galaxies such as M 82. However, it is the extended cloud environment, rather than the cores, that serves as a useful template when telescopes do not resolve such extended regions in galaxies., We thank the Spanish MICIU for funding support under grants AYA2017-85111-P and PID2019-106110GB-I00.
Published: 2021

15. Tracers of the ionization fraction in dense and translucent gas: I. Automated exploitation of massive astrochemical model grids

Author: Emeric Bron, Antoine Roueff, Nicolas Peretto, Franck Le Petit, Albrecht Sievers, Viviana V. Guzmán, François Levrier, David Languignon, Victor de Souza Magalhaes, Javier R. Goicoechea, E. Roueff, Annie Hughes, Pierre Chainais, Mathilde Gaudel, Karin I. Öberg, Sébastien Bardeau, Maryvonne Gerin, Jacques Le Bourlot, Jouni Kainulainen, Harvey S. Liszt, Pierre Gratier, Jan H. Orkisz, Maxime Vono, Jérôme Pety, Centre National de la Recherche Scientifique (France), Centre National D'Etudes Spatiales (France), Ministerio de Ciencia, Innovación y Universidades (España), 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)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), FORMATION STELLAIRE 2020, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Pontificia Universidad Católica de Chile (UC), Onsala Space Observatory (OSO), Chalmers University of Technology [Göteborg], Signal et Communications (IRIT-SC), Institut de recherche en informatique de Toulouse (IRIT), Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées, Centre de Recherche en Informatique, Signal et Automatique de Lille - UMR 9189 (CRIStAL), Centrale Lille-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Instituto de Física Fundamental [Madrid] (IFF), 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), Astrophysique, Laboratoire de physique de l'ENS - ENS Paris (LPENS (UMR_8023)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), National Radio Astronomy Observatory [Charlottesville] (NRAO), National Radio Astronomy Observatory (NRAO), Harvard-Smithsonian Center for Astrophysics (CfA), Smithsonian Institution-Harvard University [Cambridge], School of Physics and Astronomy [Cardiff], Cardiff University, Institut FRESNEL (FRESNEL), Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU), PhyTI (PhyTI), Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU), Programme National 'Physique et Chimie du Milieu Interstel-laire' (PCMI) of CNRS/INSU with INC/INP, co-funded by CEA and CNES, MIT Iinterdisciplinary programs, Paris Observatory through the AFAstrochimie program, Spanish MICI - grant AYA2017-85111-P, 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), École normale supérieure - Paris (ENS-PSL), 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), Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT)-Université de Toulouse (UT)-Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Toulouse Mind & Brain Institut (TMBI), Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Laboratoire de physique de l'ENS - ENS Paris (LPENS), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Département de Physique de l'ENS-PSL, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Département de Physique de l'ENS-PSL, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Harvard University-Smithsonian Institution, Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), and Harvard University [Cambridge]-Smithsonian Institution
Subjects: Astrochemistry, 010504 meteorology & atmospheric sciences, FOS: Physical sciences, Flux, Fraction (chemistry), Context (language use), Astrophysics, ISM: clouds, 7. Clean energy, 01 natural sciences, Ionization, TRACER, 0103 physical sciences, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Methods: statistical, 0105 earth and related environmental sciences, Physics, Methods: numerical, Molecular cloud, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, ISM: molecules, ISM: lines and bands, Interstellar medium, [SDU]Sciences of the Universe [physics], 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA)
Abstract: 28 pags., 15 figs., 12 tabs., Context. The ionization fraction in the neutral interstellar medium (ISM) plays a key role in the physics and chemistry of the ISM, from controlling the coupling of the gas to the magnetic field to allowing fast ion-neutral reactions that drive interstellar chemistry. Most estimations of the ionization fraction have relied on deuterated species such as DCO+, whose detection is limited to dense cores representing an extremely small fraction of the volume of the giant molecular clouds that they are part of. As large field-of-view hyperspectral maps become available, new tracers may be found. The growth of observational datasets is paralleled by the growth of massive modeling datasets and new methods need to be devised to exploit the wealth of information they contain. Aims. We search for the best observable tracers of the ionization fraction based on a grid of astrochemical models, with the broader aim of finding a general automated method applicable to searching for tracers of any unobservable quantity based on grids of models. Methods. We built grids of models that randomly sample a large range of physical conditions (unobservable quantities such as gas density, temperature, elemental abundances, etc.) and computed the corresponding observables (line intensities, column densities) and the ionization fraction. We estimated the predictive power of each potential tracer by training a random forest model to predict the ionization fraction from that tracer, based on these model grids. Results. In both translucent medium and cold dense medium conditions, we found several observable tracers with very good predictive power for the ionization fraction. Many tracers in cold dense medium conditions are found to be better and more widely applicable than the traditional DCO+/HCO+ ratio. We also provide simpler analytical fits for estimating the ionization fraction from the best tracers, and for estimating the associated uncertainties. We discuss the limitations of the present study and select a few recommended tracers in both types of conditions. Conclusions. The method presented here is very general and can be applied to the measurement of any other quantity of interest (cosmic ray flux, elemental abundances, etc.) from any type of model (PDR models, time-dependent chemical models, etc.)., This work was supported in part by the Programme National “Physique et Chimie du Milieu Interstellaire” (PCMI) of CNRS/INSU with INC/INP, co-funded by CEA and CNES. This project has received financial support from the CNRS through the MITI interdisciplinary programs. The authors also acknowledge funding by Paris Observatory through the AF Astrochimie program. J.R.G. thanks Spanish MICI for funding support under grant AYA2017-85111-P.
Published: 2020
Full Text: View/download PDF

16. C18O, 13CO, and 12CO abundances and excitation temperatures in the Orion B molecular cloud

Author: Emeric Bron, Marc-Antoine Miville-Deschenes, Pierre Gratier, Jérôme Pety, Jan H. Orkisz, Nicolas Peretto, Maxime Vono, Evelyne Roueff, Antoine Roueff, Albrecht Sievers, Javier R. Goicoechea, Jacques Le Bourlot, Victor de Souza Magalhaes, Jouni Kainulainen, Annie Hughes, Franck Petit, Viviana V. Guzmán, Maryvonne Gerin, Harvey S. Liszt, François Levrier, Antoine Marchal, Jocelyn Chanussot, David Languignon, Sébastien Bardeau, M. Gaudel, Pierre Chainais, Centre National de la Recherche Scientifique (France), Max Planck Society, Instituto Geográfico Nacional (España), European Space Agency, Centre National D'Etudes Spatiales (France), Agencia Estatal de Investigación (España), PhyTI (PhyTI), Institut FRESNEL (FRESNEL), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), 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), École normale supérieure - Paris (ENS-PSL), 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), FORMATION STELLAIRE 2020, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Astrophysique, Laboratoire de physique de l'ENS - ENS Paris (LPENS), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Département de Physique de l'ENS-PSL, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Département de Physique de l'ENS-PSL, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Instituto de Física Fundamental [Madrid] (IFF), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Onsala Space Observatory (OSO), Chalmers University of Technology [Göteborg], Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), Signal et Communications (IRIT-SC), Institut de recherche en informatique de Toulouse (IRIT), Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT)-Université de Toulouse (UT)-Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Toulouse Mind & Brain Institut (TMBI), Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT), GIPSA - Signal Images Physique (GIPSA-SIGMAPHY), GIPSA Pôle Sciences des Données (GIPSA-PSD), Grenoble Images Parole Signal Automatique (GIPSA-lab), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Grenoble Images Parole Signal Automatique (GIPSA-lab), Université Grenoble Alpes (UGA), Centre de Recherche en Informatique, Signal et Automatique de Lille - UMR 9189 (CRIStAL), Centrale Lille-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Pontificia Universidad Católica de Chile (UC), Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Laboratoire Univers et Théories (LUTH (UMR_8102)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), National Radio Astronomy Observatory [Charlottesville] (NRAO), National Radio Astronomy Observatory (NRAO), Canadian Institute for Theoretical Astrophysics (CITA), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Cardiff University, ANR-19-P3IA-0003,MIAI,MIAI @ Grenoble Alpes(2019), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), 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)-CY Cergy Paris Université (CY), Laboratoire de physique de l'ENS - ENS Paris (LPENS (UMR_8023)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Onsala Space Observatory, Université Toulouse 1 Capitole (UT1)-Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse 1 Capitole (UT1)-Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Ecole Centrale de Lille-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Météo France-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Météo France-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU), 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), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-École normale supérieure - Paris (ENS Paris), Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse 1 Capitole (UT1), 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), Université de Lille-Ecole Centrale de Lille-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)
Subjects: statistical [Methods], Astrophysics, 7. Clean energy, 01 natural sciences, Molecular physics, ISM: clouds, Spectral line, Methods: data analysis, 0103 physical sciences, Radiative transfer, Astrophysics::Solar and Stellar Astrophysics, Isotopologue, [INFO]Computer Science [cs], data analysis [Methods], 010303 astronomy & astrophysics, molecules [ISM], Astrophysics::Galaxy Astrophysics, Methods: statistical, Line (formation), Physics, 010308 nuclear & particles physics, Molecular cloud, Estimator, Velocity dispersion, Astronomy and Astrophysics, ISM: molecules, 3. Good health, 13. Climate action, Space and Planetary Science, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], clouds [ISM], Excitation
Abstract: 27 pags., 23 figs., 3 tabs., Context. CO isotopologue transitions are routinely observed in molecular clouds for the purpose of probing the column density of the gas and the elemental ratios of carbon and oxygen, in addition to tracing the kinematics of the environment. Aims. Our study is aimed at estimating the abundances, excitation temperatures, velocity field, and velocity dispersions of the three main CO isotopologues towards a subset of the Orion B molecular cloud, which includes IC 434, NGC 2023, and the Horsehead pillar. Methods. We used the Cramer Rao bound (CRB) technique to analyze and estimate the precision of the physical parameters in the framework of local-thermodynamic-equilibrium (LTE) excitation and radiative transfer with added white Gaussian noise. We propose a maximum likelihood estimator to infer the physical conditions from the 1-0 and 2-1 transitions of CO isotopologues. Simulations show that this estimator is unbiased and proves efficient for a common range of excitation temperatures and column densities (Tex > 6 K, N > 1014-1015 cm-2). Results. Contrary to general assumptions, the various CO isotopologues have distinct excitation temperatures and the line intensity ratios between different isotopologues do not accurately reflect the column density ratios. We find mean fractional abundances that are consistent with previous determinations towards other molecular clouds. However, significant local deviations are inferred, not only in regions exposed to the UV radiation field, but also in shielded regions. These deviations result from the competition between selective photodissociation, chemical fractionation, and depletion on grain surfaces. We observe that the velocity dispersion of the C18O emission is 10% smaller than that of 13CO. The substantial gain resulting from the simultaneous analysis of two different rotational transitions of the same species is rigorously quantified. Conclusions. The CRB technique is a promising avenue for analyzing the estimation of physical parameters from the fit of spectral lines. Future works will generalize its application to non-LTE excitation and radiative transfer methods., This work is based on observations carried out under project numbers 019-13, 022-14, 145-14, 122-15, 018-16, and finally the large program number 124-16 with the IRAM 30m telescope. IRAM is supported by INSU/CNRS (France), MPG (Germany) and IGN (Spain). This research also used data from the Herschel Gould Belt survey (HGBS) project (http:// gouldbelt-herschel.cea.fr). The HGBS is a Herschel Key Programme jointly carried out by SPIRE Specialist Astronomy Group 3 (SAG 3), scientists of several institutes in the PACS Consortium (CEA Saclay, INAF-IFSI Rome and INAF-Arcetri, KU Leuven, MPIA Heidelberg), and scientists of the Herschel Science Center (HSC). We thank CIAS for their hospitality during the many workshops devoted to the ORION-B project. This project has received financial support from the CNRS through the MITI interdisciplinary programs. This work was supported in part by the Programme National “Physique et Chimie du Milieu Interstellaire” (PCMI) of CNRS/INSU with INC/INP, co-funded by CEA and CNES. JRG thanks Spanish MICI for funding support under grant AYA2017- 85111-P. Finally, we thank the anonymous referee for helpful comments on the manuscript.
Published: 2020
Full Text: View/download PDF

17. CF+excitation in the interstellar medium

Author: Ernesto Quintas-Sánchez, Javier R. Goicoechea, François Lique, Richard Dawes, Benjamin Desrousseaux, Institut Universitaire de France, Centre National de la Recherche Scientifique (France), Centre National D'Etudes Spatiales (France), Agencia Estatal de Investigación (España), Department of Energy (US), Laboratoire Ondes et Milieux Complexes (LOMC), Centre National de la Recherche Scientifique (CNRS)-Université Le Havre Normandie (ULH), Normandie Université (NU)-Normandie Université (NU), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), 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), Department of Chemistry, Missouri University of Science and Technology, 142 Schrenk Hall, 400 West 11th Street, Rolla, Missouri 65409, United States, Missouri University of Science and Technology (Missouri S&T), University of Missouri System-University of Missouri System, AYA2017-85111-P, MICIU, DE-SC0019740, Department of Energy Office of Science, Office of Basic Energy Sciences, Université Le Havre Normandie (ULH), Normandie Université (NU)-Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS-PSL), Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), and Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Thermodynamic equilibrium, Interstellar cloud, FOS: Physical sciences, Astrophysics, 7. Clean energy, 01 natural sciences, Scattering, Ionization, 0103 physical sciences, Radiative transfer, Astrophysics::Solar and Stellar Astrophysics, Masers, Emission spectrum, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, ISM: general, Physics, 010304 chemical physics, general [ISM], Molecular data, Molecular cloud, Photodissociation, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Interstellar medium, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Atomic physics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: 6 pags., 5 figs., 1 tab., The detection of CF+ in interstellar clouds potentially allows astronomers to infer the elemental fluorine abundance and the ionization fraction in ultraviolet-illuminated molecular gas. Because local thermodynamic equilibrium (LTE) conditions are hardly fulfilled in the interstellar medium (ISM), the accurate determination of the CF+ abundance requires one to model its non-LTE excitation via both radiative and collisional processes. Here, we report quantum calculations of rate coefficients for the rotational excitation of CF+ in collisions with para- and ortho-H2 (for temperatures up to 150 K). As an application, we present non-LTE excitation models that reveal population inversion in physical conditions typical of ISM photodissociation regions (PDRs). We successfully applied these models to fit the CF+ emission lines previously observed toward the Orion Bar and Horsehead PDRs. The radiative transfer models achieved with these new rate coefficients allow the use of CF+ as a powerful probe to study molecular clouds exposed to strong stellar radiation fields., F.L. acknowledges financial support from the Institut Universitaire de France. We acknowledge the Programme National Physique et Chimie du Milieu Interstellaire (PCMI) of CNRS/INSU with INC/INP co-funded by CEA and CNES. This work was granted access to the Occigen HPC resources of CINES under the allocation 2019 [A0070411036] made by GENCI. J.R.G. thanks the Spanish MICIU for funding support under grants AYA2017-85111-P and PID2019-106110GB-I00. R.D. is supported by the US Department of Energy Office of Science, Office of Basic Energy Sciences (Award DE-SC0019740).
Published: 2020
Full Text: View/download PDF

18. Quantitative inference of the H2 column densities from 3 mm molecular emission: A case study towards Orion B

Author: Javier R. Goicoechea, M. Gaudel, Victor de Souza Magalhaes, François Levrier, David Languignon, Maryvonne Gerin, Franck Petit, Viviana V. Guzmán, Pierre Chainais, Annie Hughes, Albrecht Sievers, Harvey S. Liszt, Pierre Gratier, Jan H. Orkisz, Maxime Vono, Sébastien Bardeau, Nicolas Peretto, Jocelyn Chanussot, Jérôme Pety, Jacques Le Bourlot, Evelyne Roueff, Antoine Roueff, Jouni Kainulainen, Emeric Bron, FORMATION STELLAIRE 2020, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), 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)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Institut FRESNEL (FRESNEL), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), PhyTI (PhyTI), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), Onsala Space Observatory, Chalmers University of Technology [Göteborg], Signal et Communications (IRIT-SC), Institut de recherche en informatique de Toulouse (IRIT), Université Toulouse 1 Capitole (UT1)-Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse 1 Capitole (UT1)-Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, GIPSA - Signal Images Physique (GIPSA-SIGMAPHY), GIPSA Pôle Sciences des Données (GIPSA-PSD), Grenoble Images Parole Signal Automatique (GIPSA-lab), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Grenoble Images Parole Signal Automatique (GIPSA-lab), Université Grenoble Alpes (UGA), Centre de Recherche en Informatique, Signal et Automatique de Lille - UMR 9189 (CRIStAL), Université de Lille-Ecole Centrale de Lille-Centre National de la Recherche Scientifique (CNRS), Instituto de Física Fundamental [Madrid] (IFF), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Pontificia Universidad Católica de Chile (UC), Institut de recherche en astrophysique et planétologie (IRAP), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Météo France-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Météo France-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS), Laboratoire de physique de l'ENS - ENS Paris (LPENS (UMR_8023)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), National Radio Astronomy Observatory [Charlottesville] (NRAO), National Radio Astronomy Observatory (NRAO), School of Physics and Astronomy [Cardiff], Cardiff University, CNRS through the MITI interdisciplinary programs, Spanish MICI under grant AYA2017-85111-P, ORION-B project, Programme National 'Physique et Chimie du Milieu Interstellaire' (PCMI) - CNRS/INSU - INC/INP, co-funded by CEA and CNES, IRAM supported by INSU/CNRS (France), MPG (Germany) and IGN (Spain), Data from the CEA Herschel Gould Belt survey (HGBS) project (http://gouldbelt-herschel.cea.fr), HGBS : Herschel Key Programme, SPIRE Specialist Astronomy Group 3 (SAG 3), PACS Consortium (CEA Saclay, INAF-IFSI Rome INAF-Arcetri,KU Leuven, MPIA Heidelberg), Herschel Science Center (HSC), Université de Bordeaux (UB)-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 et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), École normale supérieure - Paris (ENS-PSL), 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), Chalmers University of Technology [Gothenburg, Sweden], Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT)-Université de Toulouse (UT)-Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Toulouse Mind & Brain Institut (TMBI), Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT), Apprentissage de modèles à partir de données massives (Thoth), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Centrale Lille-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Astrophysique, Laboratoire de physique de l'ENS - ENS Paris (LPENS), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Département de Physique de l'ENS-PSL, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Département de Physique de l'ENS-PSL, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), ANR-19-P3IA-0003,MIAI,MIAI @ Grenoble Alpes(2019), Laboratoire Univers et Théories (LUTH (UMR_8102)), 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), Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU), Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU), Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse 1 Capitole (UT1), 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), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-École normale supérieure - Paris (ENS Paris), Centre National de la Recherche Scientifique (France), Max Planck Society, Instituto Geográfico Nacional (España), Université Paris-Saclay, Istituto Nazionale di Astrofisica, and Ministerio de Ciencia, Innovación y Universidades (España)
Subjects: statistical [Methods], Field (physics), Astro-ph.IM, FOS: Physical sciences, Context (language use), Astrophysics, 7. Clean energy, 01 natural sciences, Column (database), ISM: clouds, 0103 physical sciences, Angular resolution, [INFO]Computer Science [cs], 010303 astronomy & astrophysics, Stellar density, Instrumentation and Methods for Astrophysics (astro-ph.IM), molecules [ISM], Astrophysics::Galaxy Astrophysics, Line (formation), Physics, methods: statistical, 010308 nuclear & particles physics, Molecular cloud, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, ISM: molecules, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Astrophysics of Galaxies (astro-ph.GA), Millimeter, Astrophysics - Instrumentation and Methods for Astrophysics, Astro-ph.GA, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], clouds [ISM]
Abstract: 27 pags., 19 figs., 4 tabs., Molecular hydrogen being unobservable in cold molecular clouds, the column density measurements of molecular gas currently rely either on dust emission observation in the far-IR or on star counting. (Sub-)millimeter observations of numerous trace molecules are effective from ground based telescopes, but the relationships between the emission of one molecular line and the H2 column density (NH2) is non-linear and sensitive to excitation conditions, optical depths, abundance variations due to the underlying physico-chemistry. We aim to use multi-molecule line emission to infer NH2 from radio observations. We propose a data-driven approach to determine NH2 from radio molecular line observations. We use supervised machine learning methods (Random Forests) on wide-field hyperspectral IRAM-30m observations of the Orion B molecular cloud to train a predictor of NH2, using a limited set of molecular lines as input, and the Herschel-based dust-derived NH2 as ground truth output. For conditions similar to the Orion B molecular cloud, we obtain predictions of NH2 within a typical factor of 1.2 from the Herschel-based estimates. An analysis of the contributions of the different lines to the predictions show that the most important lines are $^{13}$CO(1-0), $^{12}$CO(1-0), C$^{18}$O(1-0), and HCO$^+$(1-0). A detailed analysis distinguishing between diffuse, translucent, filamentary, and dense core conditions show that the importance of these four lines depends on the regime, and that it is recommended to add the N$_2$H$^+$(1-0) and CH$_3$OH(20-10) lines for the prediction of NH2 in dense core conditions. This article opens a promising avenue to directly infer important physical parameters from the molecular line emission in the millimeter domain. The next step will be to try to infer several parameters simultaneously (e.g., NH2 and far-UV illumination field) to further test the method. [Abridged], This work is based on observations carried out under project numbers 019-13, 022-14, 145-14, 122-15, 018-16, and finally the large program number 124-16 with the IRAM 30 m telescope. IRAM is supported by INSU/CNRS (France), MPG (Germany) and IGN (Spain). This research also used data from the Herschel Gould Belt survey (HGBS) project (http:// gouldbelt-herschel.cea.fr). The HGBS is a Herschel Key Programme jointly carried out by SPIRE Specialist Astronomy Group 3 (SAG 3), scientists of several institutes in the PACS Consortium (CEA Saclay, INAF-IFSI Rome and INAF-Arcetri, KU Leuven, MPIA Heidelberg), and scientists of the Herschel Science Center (HSC). We thank CIAS for their hospitality during the many workshops devoted to the ORION-B project. This work was supported in part by the Programme National “Physique et Chimie du Milieu Interstellaire” (PCMI) of CNRS/INSU with INC/INP, co-funded by CEA and CNES. This project has received financial support from the CNRS through the MITI interdisciplinary programs. J.R.G. thanks Spanish MICI for funding support under grant AYA2017-85111-P.
Published: 2020
Full Text: View/download PDF

19. Bringing high spatial resolution to the far-infrared: A giant leap for astrophysics

Author: Sergio Molinari, Hendrik Linz, Jerome Amiaux, Floris van der Tak, Marc Sauvage, Frank Helmich, Divya Bhatia, Javier R. Goicoechea, Volker Ossenkopf-Okada, Jorge L. Pineda, Matthias Lezius, Martina C. Wiedner, Henrik Beuther, Luisa Buinhas, Eva Schinnerer, Roger Förstner, Oliver Krause, Maryvonne Gerin, Yao Liu, Urs U. Graf, Gilles Durand, Projekt DEAL, German Centre for Air and Space Travel, European Commission, German Research Foundation, and Agencia Estatal de Investigación (España)
Subjects: Instrumentation: High angular resolution, Protoplanetary discs, Galaxies: Star formation, Spica, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 7. Clean energy, 01 natural sciences, Far infrared, Spitzer Space Telescope, Star formation [Galaxies], Planet, 0103 physical sciences, Spectral resolution, 010306 general physics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, General [ISM], Planetary habitability, Astronomy and Astrophysics, Galaxy, Far-Infrared, 13. Climate action, Space and Planetary Science, ISM: General, Formation [Stars], Satellite, Original Article, Astrophysics::Earth and Planetary Astrophysics, Stars: Formation, High angular resolution [Instrumentation]
Abstract: 37 pags., 12 figs., 1 tab., The far-infrared (FIR) regime is one of the wavelength ranges where no astronomical data with sub-arcsecond spatial resolution exist. None of the medium-term satellite projects like SPICA, Millimetron, or the Origins Space Telescope will resolve this malady. For many research areas, however, information at high spatial and spectral resolution in the FIR, taken from atomic fine-structure lines, from highly excited carbon monoxide (CO), light hydrides, and especially from water lines would open the door for transformative science. A main theme will be to trace the role of water in proto-planetary discs, to observationally advance our understanding of the planet formation process and, intimately related to that, the pathways to habitable planets and the emergence of life. Furthermore, key observations will zoom into the physics and chemistry of the star-formation process in our own Galaxy, as well as in external galaxies. The FIR provides unique tools to investigate in particular the energetics of heating, cooling, and shocks. The velocity-resolved data in these tracers will reveal the detailed dynamics engrained in these processes in a spatially resolved fashion, and will deliver the perfect synergy with ground-based molecular line data for the colder dense gas., Open Access funding enabled and organized by Projekt DEAL. The investigations by H.L., D.B., L.B., R.F. and M.L. have been funded by the German Space Agency (DLR) under FKZ 50NA1816– 19. H.B. acknowledges support from the European Research Council under the Horizon 2020 Framework Program via the ERC Consolidator Grant CSF-648505. H.B. also acknowledges support from the Deutsche Forschungsgemeinschaft in the Collaborative Research Center (SFB 881) “The Milky Way System” (subproject B1). J.R.G. thanks the Spanish MICIU for funding support under grant AYA2017-85111-P. V.O.-O. and U.G. were supported by the Collaborative Research Centre 956, sub-projects C1 and D2, funded by the Deutsche Forschungsgemeinschaft (DFG), project ID 184018867
Published: 2020

20. Expanding bubbles in Orion A: [C II] observations of M 42, M 43, and NGC 1977

Author: S. Kabanovic, Ronan Higgins, Olivier Berné, Rolf Güsten, Javier R. Goicoechea, C. H. M. Pabst, Aggm Tielens, D. Teyssier, J. Stutzki, E. Chambers, National Aeronautics and Space Administration (US), University of Stuttgart, European Commission, Ministerio de Ciencia, Innovación y Universidades (España), Dutch Research Council, Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)
Subjects: Bubble, ISM [Infrared], FOS: Physical sciences, Context (language use), Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, 7. Clean energy, 0103 physical sciences, Orion Nebula, Astrophysics::Solar and Stellar Astrophysics, Spectral resolution, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Line (formation), Physics, ISM: kinematics and dynamics, Infrared: ISM, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010308 nuclear & particles physics, Molecular cloud, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, bubbles [ISM], Interstellar medium, kinematics and dynamics [ISM], Stars, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Astrophysics of Galaxies (astro-ph.GA), Astrophysics::Earth and Planetary Astrophysics, ISM: bubbles
Abstract: 26 pags., 33 figs., 10 tabs., Context. The Orion Molecular Cloud is the nearest massive-star forming region. Massive stars have profound effects on their environment due to their strong radiation fields and stellar winds. Stellar feedback is one of the most crucial cosmological parameters that determine the properties and evolution of the interstellar medium in galaxies. Aims. We aim to understand the role that feedback by stellar winds and radiation play in the evolution of the interstellar medium. Velocity-resolved observations of the [C » II] 158 μm fine-structure line allow us to study the kinematics of UV-illuminated gas. Here, we present a square-degree-sized map of [C » II] emission from the Orion Nebula complex at a spatial resolution of 16′′ and high spectral resolution of 0.2 km s-1, covering the entire Orion Nebula (M 42) plus M 43 and the nebulae NGC 1973, 1975, and 1977 to the north. We compare the stellar characteristics of these three regions with the kinematics of the expanding bubbles surrounding them. Methods. We use [C » II] 158 μm line observations over an area of 1.2 deg2 in the Orion Nebula complex obtained by the upGREAT instrument onboard SOFIA. Results. The bubble blown by the O7V star θ1 Ori C in the Orion Nebula expands rapidly, at 13 km s-1. Simple analytical models reproduce the characteristics of the hot interior gas and the neutral shell of this wind-blown bubble and give us an estimate of the expansion time of 0.2 Myr. M 43 with the B0.5V star NU Ori also exhibits an expanding bubble structure, with an expansion velocity of 6 km s-1. Comparison with analytical models for the pressure-driven expansion of H » II regions gives an age estimate of 0.02 Myr. The bubble surrounding NGC 1973, 1975, and 1977 with the central B1V star 42 Orionis expands at 1.5 km s-1, likely due to the over-pressurized ionized gas as in the case of M 43. We derive an age of 0.4 Myr for this structure. Conclusions. We conclude that the bubble of the Orion Nebula is driven by the mechanical energy input by the strong stellar wind from θ1 Ori C, while the bubbles associated with M 43 and NGC 1977 are caused by the thermal expansion of the gas ionized by their central later-type massive stars., This work is based 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 NNA17BF53C, and the Deutsches SOFIA Institut (DSI) under DLR contract 50 OK 0901 to the University of Stuttgart. J.R.G. thanks the ERC and the Spanish MCIU for funding support under grants ERC-2013- Syg-610256-NANOCOSMOS and AYA2017-85111-P, respectively. Research on the interstellar medium at Leiden Observatory is supported through a Spinoza award of the Dutch Science Organisation (NWO).
Published: 2020
Full Text: View/download PDF

21. Distribution of Water Vapor in Molecular Clouds. II

Author: Edwin A. Bergin, Javier R. Goicoechea, Paul F. Goldsmith, David Hollenbach, Gary J. Melnick, Michael J. Kaufman, Dariusz C. Lis, David A. Neufeld, Ronald L. Snell, Eduardo González-Alfonso, Volker Tolls, National Aeronautics and Space Administration (US), NASA Jet Propulsion Laboratory, California Institute of Technology, and Ministerio de Ciencia, Innovación y Universidades (España)
Subjects: Astrochemistry, Interstellar abundances, 010504 meteorology & atmospheric sciences, Young stellar object, FOS: Physical sciences, Field strength, Astrophysics, 01 natural sciences, 0103 physical sciences, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, geography, geography.geographical_feature_category, Molecular cloud, Lead (sea ice), Astronomy and Astrophysics, Interstellar molecules, Astrophysics - Astrophysics of Galaxies, Space and Planetary Science, Ridge, Astrophysics of Galaxies (astro-ph.GA), Outflow, Water vapor
Abstract: 26 pags., 23 figs., 1 tab., The depth-dependent abundance of both gas-phase and solid-state water within dense, quiescent, molecular clouds is important to both the cloud chemistry and gas cooling. Where water is in the gas phase, it is free to participate in the network of ion-neutral reactions that lead to a host of oxygen-bearing molecules, and its many ortho- A nd para-energy levels make it an effective coolant for gas temperatures greater than 20 K. Where water is abundant as ice on grain surfaces, and unavailable to cool the gas, significant amounts of oxygen are removed from the gas phase, suppressing the gas-phase chemical reactions that lead to a number of oxygen-bearing species, including O. Models of far-UV (FUV)-illuminated clouds predict that the gas-phase water abundance peaks in the range 3 and 8 mag of the cloud surface, depending on the gas density and FUV field strength. Deeper within such clouds, water is predicted to exist mainly as ice on grain surfaces. More broadly, these models are used to analyze a variety of other regions, including outflow cavities associated with young stellar objects and the surface layers of protoplanetary disks. In this paper, we report the results of observational tests of FUV-illuminated cloud models toward the Orion Molecular Ridge and Cepheus B using data obtained from the Herschel Space Observatory and the Five College Radio Astronomy Observatory. Toward Orion, 2220 spatial positions were observed along the face-on Orion Ridge in the HO 1-1 557 GHz and NH J, K = 1,0-0,0 572 GHz lines. Toward Cepheus B, two strip scans were made in the same lines across the edge-on ionization front. These new observations demonstrate that gas-phase water exists primarily within a few magnitudes of dense cloud surfaces, strengthening the conclusions of an earlier study based on a much smaller data set, and indirectly supports the prediction that water ice is quite abundant in dense clouds., Support for this work was provided by NASA Astrophysics Data Analysis Program (ADAP) grant NNX13AF16G and an award issued by JPL/Caltech. Part of this research was carried out in part at the Jet Propulsion Laboratory, which is operated for NASA by the California Institute of Technology. J.R.G. thanks the Spanish MICIU for funding support under grant AYA2017-85111-P
Published: 2020

22. Molecular globules in the Veil bubble of Orion: IRAM 30 m 12CO, 13CO, and C18O (2-1) expanded maps of Orion A

Author: S. Suri, S. Kabanovic, C. Kramer, Nuria Marcelino, Alvaro Hacar, Aggm Tielens, C. H. M. Pabst, Ronan Higgins, Javier R. Goicoechea, D. Teyssier, S. Cuadrado, Olivier Berné, Mark G. Wolfire, J. Stutzki, M. G. Santa-Maria, Christof Buchbender, National Aeronautics and Space Administration (US), University of Stuttgart, Ames Research Center, and Ministerio de Ciencia, Innovación y Universidades (España)
Subjects: HII regions, Young stellar object, Shell (structure), FOS: Physical sciences, Astrophysics, medicine.disease_cause, 7. Clean energy, 01 natural sciences, ISM: clouds, 0103 physical sciences, ISM [Galaxies], Cluster (physics), medicine, 010303 astronomy & astrophysics, Physics, ISM: individual objects: Orion, 010308 nuclear & particles physics, Star formation, Molecular cloud, Local standard of rest, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, bubbles [ISM], Stars, Galaxies: ISM, individual objects: Orion [ISM], 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), ISM: bubbles, clouds [ISM], Ultraviolet
Abstract: 18 pags., 21 figs., 5 tabs, 1 app., Strong winds and ultraviolet (UV) radiation from O-type stars disrupt and ionize their molecular core birthplaces, sweeping up material into parsec-size shells. Owing to dissociation by starlight, the thinnest shells are expected to host low molecular abundances and therefore little star formation. Here, we expand previous maps made with observations using the IRAM 30 m telescope (at 11″ ≃ 4500 AU resolution) and present square-degree 12CO and 13CO (J = 2-1) maps of the wind-driven "Veil bubble"that surrounds the Trapezium cluster and its natal Orion molecular core (OMC). Although widespread and extended CO emission is largely absent from the Veil, we show that several CO "globules"exist that are blueshifted in velocity with respect to OMC and are embedded in the [C » II] 158 μm-bright shell that confines the bubble. This includes the first detection of quiescent CO at negative local standard of rest velocities in Orion. Given the harsh UV irradiation conditions in this translucent material, the detection of CO globules is surprising. These globules are small (Rg = 7100 AU), not massive (Mg = 0.3 M⊙ ), and are moderately dense: nH = 4 × 104 cm-3 (median values). They are confined by the external pressure of the shell, Pext∕ k ≳ 107 cm-3 K, and are likely magnetically supported. They are either transient objects formed by instabilities or have detached from pre-existing molecular structures, sculpted by the passing shock associated with the expanding shell and by UV radiation from the Trapezium. Some represent the first stages in the formation of small pillars, others of isolated small globules. Although their masses (Mg, We warmly thank the operators, AoDs, and chefs at the IRAM 30 m telescope for their support while the CO observations were conducted. This work is also based 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 NNA17BF53C, and the Deutsches SOFIA Institut (DSI) under DLR contract 50 OK 0901 to the University of Stuttgart. We acknowledge the work, during the C+ upGREAT square degree survey of Orion, of the USRA and NASA staff of the Armstrong Flight Research Center in Palmdale, the Ames Research Center in Mountain View (California), and the Deutsches SOFIA Institut. We thank the Spanish MICIU for funding support under grant AYA2017-85111-P. Research on the ISM at Leiden Observatory is supported through a Spinoza award.
Published: 2020

23. Hyperfine excitation of SH + by H

Author: Javier R. Goicoechea, Alexandre Zanchet, Octavio Roncero, François Lique, Niyazi Bulut, Laboratoire Ondes et Milieux Complexes (LOMC), Centre National de la Recherche Scientifique (CNRS)-Université Le Havre Normandie (ULH), Normandie Université (NU)-Normandie Université (NU), Insituto de Física Fundamental (CSIC), Insituto de Física Fundamental, Departamento de Química Física I, Facultad de Ciencias Químicas, Universidad Complutense de Madrid = Complutense University of Madrid [Madrid] (UCM), Firat University, 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), Centro de Investigaciones Biológicas (CSIC), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), European Commission, Institut Universitaire de France, Centre National de la Recherche Scientifique (France), Ministerio de Ciencia, Innovación y Universidades (España), and Grand Équipement National de Calcul Intensif (France)
Subjects: Hydrogen, molecular data, Atomic Physics (physics.atom-ph), Interstellar cloud, Inelastic collision, laboratory: molecular [Methods], chemistry.chemical_element, FOS: Physical sciences, methods: laboratory: molecular, 7. Clean energy, 01 natural sciences, Molecular processes, Spectral line, Physics - Atomic Physics, Physics - Space Physics, Physics - Chemical Physics, 0103 physical sciences, Radiative transfer, Emission spectrum, 010303 astronomy & astrophysics, Hyperfine structure, Instrumentation and Methods for Astrophysics (astro-ph.IM), Astrophysics::Galaxy Astrophysics, Chemical Physics (physics.chem-ph), [PHYS]Physics [physics], 010304 chemical physics, Molecular data, Molecular cloud, Polyatomic ion, Astronomy and Astrophysics, Space Physics (physics.space-ph), molecular processes, chemistry, 13. Climate action, Space and Planetary Science, radiative transfer, Atomic physics, Astrophysics - Instrumentation and Methods for Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: 5 pags., 3 figs., Context. SH+ is a surprisingly widespread molecular ion in diffuse interstellar clouds. There, it plays an important role by triggering the sulfur chemistry. In addition, SH+ emission lines have been detected at the UV-illuminated edges of dense molecular clouds, so-called photo-dissociation regions (PDRs), and toward high-mass protostars. An accurate determination of the SH+ abundance and of the physical conditions prevailing in these energetic environments relies on knowing the rate coefficients of inelastic collisions between SH+ molecules and hydrogen atoms, hydrogen molecules, and electrons. Aims. We derive SH+-H fine and hyperfine-resolved rate coefficients from recent quantum calculations for the SH+-H collisions, including inelastic, exchange, and reactive processes. Methods. The method we used is based on the infinite-order sudden approach. Results. State-to-state rate coefficients between the first 31 fine levels and 61 hyperfine levels of SH+ were obtained for temperatures ranging from 10 to 1000 K. Fine-structure resolved rate coefficients present a strong propensity rule in favor of Δj = ΔN transitions. The Δj = ΔF propensity rule is observed for the hyperfine transitions. Conclusions. The new rate coefficients will help significantly in the interpretation of SH+ spectra from PDRs and UV-irradiated shocks where the abundance of hydrogen atoms with respect to hydrogen molecules can be significant., We acknowledge the French-Spanish collaborative project PICS (Ref. PIC2017FR7). F. L. acknowledges financial support from the European Research Council (Consolidator Grant COLLEXISM, Grant agreement 811363), the Institut Universitaire de France and the Programme National “Physique et Chimie du Milieu Interstellaire” (PCMI) of CNRS/INSU with INC/INP co-funded by CEA and CNES. The research leading to these results has received funding from MICIU under grants No. FIS2017-83473-C2 and AYA2017-85111-P. N.B. acknowledges the computing facilities by TUBITAKTRUBA. This work was performed using HPC resources from GENCI-CINES (Grant A0070411036).
Published: 2020
Full Text: View/download PDF

24. Mapping the high ionization rate of the GC starburst Sgr B2 through low HCO+ /N2H+ J=1-0 intensity ratios

Author: Miriam G. Santa-Maria and Javier R. Goicoechea
Abstract: We still do not understand which mechanisms dominate the heating and ionization of the extended molecular gas in galactic nuclei. The starburst Sgr B2, in the Galactic Center (GC), is an excellent template to spatially resolve the high-mass star-forming cores from the extended cloud environment, and to study the properties of the warm neutral gas in conditions likely prevalent in star-forming galaxies. We mapped ~1000 pc2 of Sgr B2 complex, using the IRAM 30m telescope, in the N2H+, HCO+ J=1-0 and SiO J=2-1 line emission. The extended nature of the N2H+ J=1-0 emission is remarkable. Compared to molecular clouds in the disk of the galaxy, the N2H+ J=1-0 emission is not confined to cold and dense cores and filaments. This can be explained by the high ionization rate (ζ ≳10−15 s−1), leading to overabundant H+3, He+, and N2H+. The enhanced ionization rate is likely responsible of the much lower line intensity ratio RI =HCO+/N2H+ J=1-0 observed in Sgr B2 (RI ≈ 2 ± 2), Arp 220 (RI ≈ 2), and NGC 253 (RI ≈ 5), compared to disk clouds such as Orion B (RI ≈ 24) and starburst galaxies such as M82 (RI ≈ 21).
Published: 2022
Full Text: View/download PDF

25. A Fully Bayesian Approach For Inferring Physical Properties With Credibility Intervals From Noisy Astronomical Data

Author: Victor de Souza Magalhaes, Javier R. Goicoechea, Annie Hughes, Fracois Levrier, Viviana V. Guzmán, Pascal Tremblin, M. Gaudel, Karin I. Öberg, Evelyne Roueff, Antoine Roueff, Pierre Chainais, Maryvonne Gerin, Sébastien Bardeau, Jocelyn Chanussot, David Languignon, Albrecht Sievers, Franck Petit, Harvey S. Listz, Pierre Gratier, Maxime Vono, Jérôme Pety, Sébastien Bourguignon, Jan H. Orkisz, Nicolas Peretto, Emeric Bron, Jacques Le Bourlot, Jouni Kainulainen, Signal et Communications (IRIT-SC), Institut de recherche en informatique de Toulouse (IRIT), Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT)-Université de Toulouse (UT)-Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Toulouse Mind & Brain Institut (TMBI), Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT), 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 de Recherche en Informatique, Signal et Automatique de Lille - UMR 9189 (CRIStAL), Centrale Lille-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Joint ALMA Observatory (JAO), European Southern Observatory (ESO)-National Radio Astronomy Observatory (NRAO), Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Gesellschaft, Chalmers University of Technology [Göteborg], Laboratoire Univers et Théories (LUTH (UMR_8102)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Astrophysique, Laboratoire de physique de l'ENS - ENS Paris (LPENS (UMR_8023)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), National Radio Astronomy Observatory (NRAO), Umeå University, Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), School of Physics and Astronomy [Cardiff], Cardiff University, Université Paul Cézanne - Aix-Marseille 3, Instituto de RadioAstronomía Milimétrica (IRAM), 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]), Département d'Astrophysique (ex SAP) (DAP), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Departement d'Astrophysique Extragalactique et de Cosmologie (DAEC), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Laboratoire des Sciences du Numérique de Nantes (LS2N), Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-École Centrale de Nantes (ECN)-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), GIPSA - Signal Images Physique (GIPSA-SIGMAPHY), Département Images et Signal (GIPSA-DIS), Grenoble Images Parole Signal Automatique (GIPSA-lab ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-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 Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Grenoble Images Parole Signal Automatique (GIPSA-lab ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut Polytechnique de Grenoble - Grenoble Institute of Technology-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 Polytechnique de Grenoble - Grenoble Institute of Technology-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), 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), ANR-19-P3IA-0003,MIAI,MIAI @ Grenoble Alpes(2019), Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées, 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)-Université Paris Diderot - Paris 7 (UPD7), Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Université Paris Diderot - Paris 7 (UPD7)-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)-Sorbonne Université (SU)-Université Paris Diderot - Paris 7 (UPD7), Université de Nantes (UN)-Université de Nantes (UN)-École Centrale de Nantes (ECN)-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), 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), National Radio Astronomy Observatory (NRAO)-European Southern Observatory (ESO), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPC), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Université Paris Diderot - Paris 7 (UPD7)-École normale supérieure - Paris (ENS-PSL), Centre National de la Recherche Scientifique (CNRS)-École Centrale de Nantes (ECN)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), and Université de Nantes (UN)-Université de Nantes (UN)-École Centrale de Nantes (ECN)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Pointwise, [PHYS]Physics [physics], Computer science, Molecular cloud, Bayesian probability, Interstellar cloud, Estimator, 02 engineering and technology, 01 natural sciences, Physical conditions, Markov chain Monte Carlo, 13. Climate action, 0103 physical sciences, Radioastronomy, 0202 electrical engineering, electronic engineering, information engineering, Maximum a posteriori estimation, Probability distribution, 020201 artificial intelligence & image processing, Approximate Bayesian computation, [INFO]Computer Science [cs], Statistical physics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics
Abstract: International audience; The atoms and molecules of interstellar clouds emit photons when passing from an excited state to a lower energy state. The resulting emission lines can be detected by telescopes in the different wavelength domains (radio, infrared, visible, UV...). Through the excitation and chemical conditions they reveal, these lines provide key constraints on the local physical conditions reigning in giant molecular clouds (GMCs), which constitute the birthplace of stars in galaxies. Inferring these physical conditions from observed maps of GMCs using complex astrophysical models of these regions remains a complicated challenge due to potentially degenerate solutions and widely varying signal-to-noise ratios over the map. We propose a Bayesian framework to infer the probability distributions associated to each of these physical parameters, taking a spatial smoothness prior into account to tackle the challenge of low signal-to-noise ratio regions of the observed maps. A numerical astrophysical model of the cloud is involved in the likelihood within an approximate Bayesian computation (ABC) method. This enables to both infer pointwise estimators (e.g., minimum mean square or maximum a posteriori) and quantify the uncertainty associated to the estimation process. The benefits of the proposed approach are illustrated based on noisy synthetic observation maps.
Published: 2019
Full Text: View/download PDF

26. Oxygen fractionation in dense molecular clouds

Author: Pablo Riviere-Marichalar, Pierre Gratier, Jérôme Pety, Valentine Wakelam, Asunción Fuente, Viviana V. Guzmán, Nuria Marcelino, Marcelino Agúndez, Kevin M. Hickson, E. Roueff, Jean-Christophe Loison, Javier R. Goicoechea, Aurore Bacmann, Maryvonne Gerin, José Cernicharo, Franck Le Petit, Centre National de la Recherche Scientifique (France), Université de Bordeaux, Ministerio de Economía y Competitividad (España), Ministerio de Ciencia, Innovación y Universidades (España), European Commission, Max Planck Society, Instituto Geográfico Nacional (España), Institut des Sciences Moléculaires (ISM), Université Montesquieu - Bordeaux 4-Université Sciences et Technologies - Bordeaux 1-École Nationale Supérieure de Chimie et de Physique de Bordeaux (ENSCPB)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), AMOR 2019, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Joint ALMA Observatory (JAO), European Southern Observatory (ESO)-National Radio Astronomy Observatory (NRAO), 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), Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), Observatorio Astronomico Nacional, Madrid, European Space Astronomy Centre (ESAC), European Space Agency (ESA), Université Montesquieu - Bordeaux 4-Université Sciences et Technologies - Bordeaux 1-École Nationale Supérieure de Chimie et de Physique de Bordeaux (ENSCPB)-Centre National de la Recherche Scientifique (CNRS), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), 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), Laboratoire Univers et Théories (LUTH (UMR_8102)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Departement d'Astrophysique Extragalactique et de Cosmologie (DAEC), Observatoire de Paris, and PSL Research University (PSL)-PSL Research University (PSL)
Subjects: [SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], chemistry.chemical_element, FOS: Physical sciences, Fractionation, 7. Clean energy, 01 natural sciences, Oxygen, ISM: clouds, ISM: abundances, Article, 0103 physical sciences, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, abundances [ISM], Physics, [PHYS]Physics [physics], astrochemistry [Physical Data and Processes], 010308 nuclear & particles physics, Molecular cloud, Astronomy and Astrophysics, Sulfur, Astrophysics - Astrophysics of Galaxies, Physical Data and Processes: astrochemistry, Oxygen atom, chemistry, 13. Climate action, Space and Planetary Science, Chemical physics, Astrophysics of Galaxies (astro-ph.GA), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], clouds [ISM]
Abstract: 22 pags., 5 figs., We have developed the first gas-grain chemical model for oxygen fractionation (also including sulphur fractionation) in dense molecular clouds, demonstrating that gas-phase chemistry generates variable oxygen fractionation levels, with a particularly strong effect for NO, SO, O, and SO. This large effect is due to the efficiency of the neutral O + NO, O + SO, and O + O exchange reactions. The modelling results were compared to new and existing observed isotopic ratios in a selection of cold cores. The good agreement between model and observations requires that the gas-phase abundance of neutral oxygen atoms is large in the observed regions. The SO/SO ratio is predicted to vary substantially over time, showing that it can be used as a sensitive chemical proxy for matter evolution in dense molecular clouds., This work was supported by the program “Physique et Chimie du Milieu Interstellaire” (PCMI) funded by CNRS and CNES. VW researches are funded by the ERC Starting Grant (3DICE, grant agreement 336474). Computer time was provided by the Pôle Modélisation HPC facilities of the Institut des Sciences Moléculaires UMR 5255 CNRS − Université de Bordeaux, co-funded by the Nouvelle Aquitaine region. M.A., N.M., J.C. and J.R.C. thank the Spanish MICIU for funding support under grants AYA2016-75066-C2-1-P and AYA2017-85111-P, and the European Research Council for support under grant ERC2013-Syg-610256-NANOCOSMOS. M.A. also acknowledges funding support from the Ramón y Cajal programme of Spanish MICIU (RyC-2014-16277). IRAM is supported by INSU/CNRS (France), MPG (Germany) and IGN (Spain).
Published: 2019
Full Text: View/download PDF

27. Molecular tracers of radiative feedback in Orion (OMC-1) Widespread CH

Author: Javier R, Goicoechea, Miriam G, Santa-Maria, Emeric, Bron, David, Teyssier, Nuria, Marcelino, José, Cernicharo, and Sara, Cuadrado
Subjects: Article
Abstract: Young massive stars regulate the physical conditions, ionization, and fate of their natal molecular cloud and surroundings. It is important to find tracers that help quantifying the stellar feedback processes that take place at different spatial scales. We present ~85 arcmin(2) (~1.3 pc(2)) velocity-resolved maps of several submillimeter molecular lines, taken with Herschel/HIFI, toward the closest high-mass star-forming region, the Orion molecular cloud 1 core (OMC-1). The observed rotational lines include probes of warm and dense molecular gas that are difficult, if not impossible, to detect from ground-based telescopes: CH(+) (J = 1–0), CO (J = 10–9), HCO(+) (J = 6–5) and HCN (J = 6–5), and CH (N, J =1, 3/2–1, 1/2). These lines trace an extended but thin layer (A(V) ≃3–6 mag or ~10(16) cm) of molecular gas at high thermal pressure, P(th) = n(H) · T(k) ≈ 10(7) – 10(9) cm(−3) K, associated with the far ultraviolet (FUV) irradiated surface of OMC-1. The intense FUV radiation field, emerging from massive stars in the Trapezium cluster, heats, compresses and photoevaporates the cloud edge. It also triggers the formation of specific reactive molecules such as CH(+). We find that the CH(+) (J = 1–0) emission spatially correlates with the flux of FUV photons impinging the cloud: G(0) from ~10(3) to ~10(5). This correlation is supported by constant-pressure photodissociation region (PDR) models in the parameter space P(th)/G(0) ≈ [5 · 10(3) – 8 · 10(4)] cm(−3) K where many observed PDRs seem to lie. The CH(+) (J = 1–0) emission spatially correlates with the extended infrared emission from vibrationally excited H(2) (v ≥ 1), and with that of [C ii] 158 μm and CO J = 10–9, all emerging from FUV-irradiated gas. These correlations link the presence of CH(+) to the availability of C(+) ions and of FUV-pumped H(2) (v ≥ 1) molecules. We conclude that the parsec-scale CH(+) emission and narrow-line (Δv ≃ 3 km s(−1)) mid-J CO emission arises from extended PDR gas and not from fast shocks. PDR line tracers are the smoking gun of the stellar feedback from young massive stars. The PDR cloud surface component in OMC-1, with a mass density of 120–240 M(⊙) pc(−2), represents ~5% to ~10% of the total gas mass, however, it dominates the emitted line luminosity; the average CO J = 10–9 surface luminosity in the mapped region being ~35 times brighter than that of CO J = 2–1. These results provide insights into the source of submillimeter CH(+) and mid-J CO emission from distant star-forming galaxies.
Published: 2019

28. A dynamically young, gravitationally stable network of filaments in Orion B

Author: François Levrier, Nicolas Peretto, David Languignon, Javier R. Goicoechea, Harvey S. Liszt, Pierre Gratier, Viviana V. Guzmán, Pascal Tremblin, Maryvonne Gerin, Franck Le Petit, Emeric Bron, Jan H. Orkisz, Karin I. Öberg, Albrecht Sievers, Sébastien Bardeau, Annie Hughes, Evelyne Roueff, Jérôme Pety, 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), School of Physics and Astronomy [Cardiff], Cardiff University, Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), Laboratoire de Radioastronomie (LRA), 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), Astrophysique, Laboratoire de physique de l'ENS - ENS Paris (LPENS (UMR_8023)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de l'Observatoire Midi-Pyrénées (LATT), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), AMOR 2019, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Harvard-Smithsonian Center for Astrophysics (CfA), Harvard University-Smithsonian Institution, Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Gesellschaft, MIS, Laboratoire Univers et Théories (LUTH (UMR_8102)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut national 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), National Radio Astronomy Observatory (NRAO), Umeå University, Instituto de RadioAstronomía Milimétrica (IRAM), Département d'Astrophysique (ex SAP) (DAP), Institut de Recherches sur les lois Fondamentales de l'Univers (IRFU), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Université Paris-Saclay, Istituto Nazionale di Astrofisica, European Commission, Ministerio de Economía y Competitividad (España), 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), 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)-École normale supérieure - Paris (ENS Paris), 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)-Sorbonne Université (SU)-Université Paris Diderot - Paris 7 (UPD7)-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)-Sorbonne Université (SU)-Université Paris Diderot - Paris 7 (UPD7), 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), Smithsonian Institution-Harvard University [Cambridge], Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7), Laboratoire 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), Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Harvard University [Cambridge]-Smithsonian Institution, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)
Subjects: ISM: individual objects: Orion B, media_common.quotation_subject, ISM: structure, Population, FOS: Physical sciences, Astrophysics, 01 natural sciences, ISM: clouds, Protein filament, 0103 physical sciences, Gravitational collapse, Supersonic speed, data analysis [Methods], education, 010303 astronomy & astrophysics, media_common, Physics, ISM: kinematics and dynamics, education.field_of_study, radio lines: ISM, 010308 nuclear & particles physics, Star formation, Molecular cloud, Astronomy and Astrophysics, methods: data analysis, Astrophysics - Astrophysics of Galaxies, ISM [Radio lines], [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], individual objects: Orion B [ISM], kinematics and dynamics [ISM], Stars, Space and Planetary Science, Sky, Astrophysics of Galaxies (astro-ph.GA), structure [ISM], [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], clouds [ISM]
Abstract: Context. Filaments are a key step on the path that leads from molecular clouds to star formation. However, their characteristics, for instance their width, are heavily debated and the exact processes that lead to their formation and fragmentation into dense cores still remain to be fully understood. Aims. We aim at characterising the mass, kinematics, and stability against gravitational collapse of a statistically significant sample of filaments in the Orion B molecular cloud, which is renown for its very low star formation efficiency. Methods. We characterised the gas column densities and kinematics over a field of 1.9 deg2 , using C18O (J = 1−0) data from the IRAM 30 m large programme ORION-B at angular and spectral resolutions of 23.5 00 and 49.5 kHz, respectively. Using two different Hessian-based filters, we extracted and compared two filamentary networks, each containing over 100 filaments. Results. Independent of the extraction method, the filament networks have consistent characteristics. The filaments have widths of ∼0.12 ± 0.04 pc and show a wide range of linear (∼1−100 M pc−1 ) and volume densities (∼2 × 103−2 × 105 cm−3 ). Compared to previous studies, the filament population is dominated by low-density, thermally sub-critical structures, suggesting that most of the identified filaments are not collapsing to form stars. In fact, only ∼1% of the Orion B cloud mass covered by our observations can be found in super-critical, star-forming filaments, explaining the low star formation efficiency of the region. The velocity profiles observed across the filaments show quiescence in the centre and coherency in the plane of the sky, even though these profiles are mostly supersonic. Conclusions. The filaments in Orion B apparently belong to a continuum which contains a few elements comparable to already studied star-forming filaments, for example in the IC 5146, Aquila or Taurus regions, as well as many lower density, gravitationally unbound structures. This comprehensive study of the Orion B filaments shows that the mass fraction in super-critical filaments is a key factor in determining star formation efficiency., 22 pags., 15 figs., 4 tabs., 2 apps., This research has made use of data from the Herschel Gould Belt Survey (HGBS) project (http://gouldbelt-herschel.cea.fr). The HGBS is a Herschel Key Programme jointly carried out by SPIRE Specialist Astronomy Group 3 (SAG 3), scientists of several institutes in the PACS Consortium (CEA Saclay, INAF-IFSI Rome and INAF-Arcetri, KU Leuven, MPIA Heidelberg), and scientists of the Herschel Science Center (HSC). This work was supported by the CNRS/CNES programme “Physique et Chimie du Milieu Interstellaire” (PCMI). We thank the CIAS for its hospitality during the three workshops devoted to this project. N.P. wishes to acknowledge support from STFC under grant number ST/N000706/1. P.G. thanks ERC starting grant (3DICE, grant agreement 336474) for funding during this work. J.R.G. thanks the Spanish MINECO for funding support under grant AYA2017-85111-P.
Published: 2019
Full Text: View/download PDF

29. Formation of interstellar SH+ from vibrationally excited H2: Quantum study of S+ + H2 ⇄ SH+ + H reaction and inelastic collision

Author: Octavio Roncero, Javier R. Goicoechea, François Lique, Alexandre Zanchet, Niyazi Bulut, Ministerio de Ciencia, Innovación y Universidades (España), Agencia Estatal de Investigación (España), Institut Universitaire de France, Turkish Academy of Sciences, Zanchet, Alexandre [0000-0002-0471-5658], Lique, François [0000-0002-0664-2536], Roncero, Octavio [0000-0002-8871-4846], Goicoechea, Javier R. [0000-0001-7046-4319], Bulut, Niyazi [0000-0003-2863-7700], Instituto de Física Fundamental [Madrid] (IFF), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Laboratoire Ondes et Milieux Complexes (LOMC), Centre National de la Recherche Scientifique (CNRS)-Université Le Havre Normandie (ULH), Normandie Université (NU)-Normandie Université (NU), Firat University, Zanchet, Alexandre, Lique, François, Roncero, Octavio, Goicoechea, Javier R., and Bulut, Niyazi
Subjects: Physics, [PHYS]Physics [physics], Photodissociation, Inelastic collision, Astronomy and Astrophysics, Astrophysics, 01 natural sciences, Potential energy, Molecular physics, Molecular processes, ISM: molecules, 3. Good health, Photon-dominated region (PDR), Reaction rate constant, Space and Planetary Science, Yield (chemistry), Excited state, 0103 physical sciences, 010306 general physics, 010303 astronomy & astrophysics, Collisional excitation, ComputingMilieux_MISCELLANEOUS, molecules [ISM], Bar (unit)
Abstract: 8 pags., 7 figs., 4 tabs., The rate constants for the formation, destruction, and collisional excitation of SH are calculated from quantum mechanical approaches using two new SH potential energy surfaces (PESs) of A″ and A″ electronic symmetry. The PESs were developed to describe all adiabatic states correlating to the SH(ς) + H(S) channel. The formation of SH through the S + H reaction is endothermic by ≈9860 K, and requires at least two vibrational quanta on the H molecule to yield significant reactivity. Quasi-classical calculations of the total formation rate constant for H(v? =? 2) are in very good agreement with the quantum results above 100 K. Further quasi-classical calculations are then performed for v? =? 3, 4, and 5 to cover all vibrationally excited H levels significantly populated in dense photodissociation regions (PDR). The new calculated formation and destruction rate constants are two to six times larger than the previous ones and have been introduced in the Meudon PDR code to simulate the physical and illuminating conditions in the Orion bar prototypical PDR. New astrochemical models based on the new molecular data produce four times larger SH column densities, in agreement with those inferred from recent ALMA observations of the Orion bar., The research leading to these results has received funding from MICIU under grants No. FIS2017-83473-C2 and AYA2017- 85111-P. FL acknowledges financial support from the Institut Universitaire de France. NB acknowledges the computing facilities by TUBITAK-TRUBA.
Published: 2019
Full Text: View/download PDF

30. Abundances of sulphur molecules in the Horsehead nebula. First NS+ detection in a photodissociation region

Author: R. Le Gal, Javier R. Goicoechea, Evelyne Roueff, Jérôme Pety, Viviana V. Guzmán, Maryvonne Gerin, Pablo Riviere-Marichalar, Pierre Gratier, Valentine Wakelam, Asunción Fuente, Jean-Christophe Loison, Observatorio Astronómico Nacional (OAN), oan, Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), 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), AMOR 2019, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), Institut des Sciences Moléculaires (ISM), Université Montesquieu - Bordeaux 4-Université Sciences et Technologies - Bordeaux 1-École Nationale Supérieure de Chimie et de Physique de Bordeaux (ENSCPB)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Ministerio de Economía y Competitividad (España), European Commission, Ministerio de Ciencia, Innovación y Universidades (España), Centre National de la Recherche Scientifique (France), Centre National D'Etudes Spatiales (France), Ctr Astrobiol CSIC INTA, Lab Astofis Mol, Madrid 28850, Laboratoire Univers et Théories (LUTH (UMR_8102)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Université Montesquieu - Bordeaux 4-Université Sciences et Technologies - Bordeaux 1-École Nationale Supérieure de Chimie et de Physique de Bordeaux (ENSCPB)-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, PSL Research University (PSL)-PSL Research University (PSL)-Université de Cergy Pontoise (UCP), and Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS)
Subjects: Astrochemistry, 010504 meteorology & atmospheric sciences, [SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Stars: formation, FOS: Physical sciences, Context (language use), Astrophysics, Photodissociation region, 01 natural sciences, Article, ISM: abundances, Abundance (ecology), low-mass [Stars], 0103 physical sciences, Radiative transfer, Stars: low-mass, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), molecules [ISM], formation [Stars], 0105 earth and related environmental sciences, Line (formation), ISM: kinematics and dynamics, Physics, abundances [ISM], Nebula, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, ISM: molecules, Abundance of the chemical elements, 3. Good health, kinematics and dynamics [ISM], Astrophysics - Solar and Stellar Astrophysics, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA)
Abstract: 15 pags., 5 figs., 5 tabs., 1 app., Context. Sulphur is one of the most abundant elements in the Universe (S/H ~ 1.3 × 10) and plays a crucial role in biological systems on Earth. The understanding of its chemistry is therefore of major importance. Aims. Our goal is to complete the inventory of S-bearing molecules and their abundances in the prototypical photodissociation region (PDR) the Horsehead nebula to gain insight into sulphur chemistry in UV irradiated regions. Based on the WHISPER (Wide-band High-resolution Iram-30 m Surveys at two positions with Emir Receivers) millimeter (mm) line survey, our goal is to provide an improved and more accurate description of sulphur species and their abundances towards the core and PDR positions in the Horsehead. Methods. The Monte Carlo Markov chain (MCMC) methodology and the molecular excitation and radiative transfer code RADEX were used to explore the parameter space and determine physical conditions and beam-averaged molecular abundances. Results. A total of 13 S-bearing species (CS, SO, SO, OCS, HCS-both ortho and para-HDCS, CS, HCS, SO, HS, SH, NS and NS) have been detected in the two targeted positions. This is the first detection of SO in the Horsehead and the first detection of NS in any PDR. We find a differentiated chemical behaviour between C-S and O-S bearing species within the nebula. The C-S bearing species CS and o-HCS present fractional abundances a factor of > two higher in the core than in the PDR. In contrast, the O-S bearing molecules SO, SO, and OCS present similar abundances towards both positions. A few molecules, SO, NS, and NS, are more abundant towards the PDR than towards the core, and could be considered as PDR tracers. Conclusions. This is the first complete study of S-bearing species towards a PDR. Our study shows that CS, SO, and HS are the most abundant S-bearing molecules in the PDR with abundances of approximately a few 10. We recall that SH, SH, S, and S are not observable at the wavelengths covered by the WHISPER survey. At the spatial scale of our observations, the total abundance of S atoms locked in the detected species is, We thank the Spanish MINECO for funding support from AYA2016-75066-C2-1/2-P, AYA2017-85111-P and ERC under ERC-2013-SyG, G. A. 610256 NANOCOSMOS. J.R.G. thanks the Spanish MCIU for funding support under grant AYA2017-85111-P. This work was supported by the Programme National “Physique et Chimie du Milieu Interstellaire” (PCMI) of CNRS/INSU with INC/INP co-funded by CEA and CNES.
Published: 2019
Full Text: View/download PDF

31. Dynamics of cluster-forming hub-filament systems

Author: Carsten Kramer, Santiago García-Burillo, S. Suri, A. Luna, P. Didelon, M. González-García, Álvaro Sánchez-Monge, Javier Ballesteros-Paredes, Nicola Schneider, Patrick Hennebelle, S. P. Treviño-Morales, Javier R. Goicoechea, Y. N. Lee, S. Geen, Jouni Kainulainen, P. Pilleri, Pascal Tremblin, Asunción Fuente, Chalmers University of Technology [Göteborg], Universität zu Köln = University of Cologne, Max Planck Institute for Astronomy (MPIA), 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), Universidad Nacional Autónoma de México = National Autonomous University of Mexico (UNAM), Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS), Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), Instituto Nacional de Astrofísica, Óptica y Electrónica (INAOE), Instituto de Física Fundamental [Madrid] (IFF), Zentrum für Astronomie der Universität Heidelberg (ZAH), Universität Heidelberg [Heidelberg] = Heidelberg University, ANR-16-CE92-0035,GENESIS,GENeration et Evolution des Structures du milieu InterStellaire(2016), European Project: 639459,H2020,ERC-2014-STG,PROMISE(2016), European Project: 610256,EC:FP7:ERC,ERC-2013-SyG,NANOCOSMOS(2014), European Project: 648505,H2020,ERC-2014-CoG,CSF(2015), European Project: 339177,EC:FP7:ERC,ERC-2013-ADG,STARLIGHT(2014), Universität zu Köln, 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), Universidad Nacional Autónoma de México (UNAM), Centre National de la Recherche Scientifique (CNRS)-Université de La Réunion (UR)-Université Paris Diderot - Paris 7 (UPD7)-IPG PARIS-Institut national des sciences de l'Univers (INSU - CNRS), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Universität Heidelberg [Heidelberg], European Commission, Ministerio de Economía y Competitividad (España), European Research Council, German Research Foundation, Centre National D'Etudes Spatiales (France), Ministerio de Ciencia, Innovación y Universidades (España), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), and 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)
Subjects: ISM: structure, FOS: Physical sciences, macromolecular substances, Kinematics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, ISM: clouds, Article, law.invention, Quantitative Biology::Subcellular Processes, Protein filament, Accretion rate, law, 0103 physical sciences, ISM: individual objects: Monoceros R2, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Physics, ISM: kinematics and dynamics, 010308 nuclear & particles physics, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, individual objects: Monoceros R2 [ISM], kinematics and dynamics [ISM], Stars, Star cluster, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), High mass, structure [ISM], Hydrostatic equilibrium, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], clouds [ISM], Dust emission
Abstract: Context. High-mass stars and star clusters commonly form within hub-filament systems. Monoceros R2 (hereafter Mon R2), at a distance of 830 pc, harbors one of the closest of these systems, making it an excellent target for case studies. Aims. We investigate the morphology, stability and dynamical properties of the Mon R2 hub-filament system. Methods. We employed observations of the (CO)-C-13 and (CO)-O-18 1 -> 0 and 2 -> 1 lines obtained with the IRAM-30m telescope. We also used H-2 column density maps derived from Herschel dust emission observations. Results. We identified the filamentary network in Mon R-2 with the DisPerSE algorithm and characterized the individual filaments as either main (converging into the hub) or secondary (converging to a main filament). The main filaments have line masses of 30-100 M-circle dot pc(-1) and show signs of fragmentation, while the secondary filaments have line masses of 12-60 M-circle dot pc(-1) and show fragmentation only sporadically. In the context of Ostriker's hydrostatic filament model, the main filaments are thermally supercritical. If non-thermal motions are included, most of them are transcritical. Most of the secondary filaments are roughly transcritical regardless of whether non-thermal motions are included or not. From the morphology and kinematics of the main filaments, we estimate a mass accretion rate of 10(-4)-10(-3) M-circle dot yr(-1) into the central hub. The secondary filaments accrete into the main filaments at a rate of 0.1-0.4 x 10(-4) M-circle dot yr(-1). The main filaments extend into the central hub. Their velocity gradients increase toward the hub, suggesting acceleration of the gas. We estimate that with the observed infall velocity, the mass-doubling time of the hub is similar to 2.5 Myr, ten times longer than the free-fall time, suggesting a dynamically old region. These timescales are comparable with the chemical age of the HII region. Inside the hub, the main filaments show a ring-or a spiral-like morphology that exhibits rotation and infall motions. One possible explanation for the morphology is that gas is falling into the central cluster following a spiral-like pattern.© ESO 2019., S.P.T.M. and J.K.acknowledge to the European Union's Horizon 2020 research and innovation program for funding support given under grant agreement No 639459 (PROMISE). A.F. thanks the Spanish MINECO for funding support from grants AYA2016-75 066-C2-2-P, and ERC under ERC-2013-SyG, G.A. 610 256 NANOCOSMOS. A.S.M. and S. S. thank the Deutsche Forschungsgemeinschaft (DFG) for funding support via the collaborative research grant SFB 956, projects A6 and A4. P. P. acknowledges financial support from the Center National de Etudes Spatiales (CNES). N.S. acknowledges support from the French ANR and the German DFG through the project "GENESIS" (ANR-16-CE92-0035-01/DFG1591/2-1). S. S. acknowledges support from the European Research Council under the Horizon 2020 Framework Program via the ERC Consolidator Grant CSF-648 505. S.G. is funded by the European Research Council under Grant Agreement no. 339 177 (STARLIGHT) of the European Community's Seventh Framework Programme (FP7/2007-2013). J.R.G. thanks the Spanish MICIU for funding support from grant AYA2017-85 111-P.
Published: 2019
Full Text: View/download PDF

32. Direct estimation of electron density in the Orion Bar PDR from mm-wave carbon recombination lines

Author: Javier R. Goicoechea, A. G. G. M. Tielens, José Cernicharo, A. Báez-Rubio, S. Cuadrado, P. Salas, Ministerio de Ciencia, Innovación y Universidades (España), European Commission, and Netherlands Organization for Scientific Research
Subjects: Electron density, HII regions, Astrochemistry, FOS: Physical sciences, Electron, Astrophysics, Photodissociation region, 01 natural sciences, 7. Clean energy, Molecular physics, ISM: clouds, Article, Ion, 0103 physical sciences, 010303 astronomy & astrophysics, Collisional excitation, Hyperfine structure, Physics, 010308 nuclear & particles physics, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, 3. Good health, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Photon-dominated region, clouds [ISM], Excitation
Abstract: 6 pags., 3 figs., 1 app., Context. A significant fraction of the molecular gas in star-forming regions is irradiated by stellar UV photons. In these environments, the electron density (ne) plays a critical role in the gas dynamics, chemistry, and collisional excitation of certain molecules. Aims. We determine ne in the prototypical strongly irradiated photodissociation region (PDR), the Orion Bar, from the detection of new millimeter-wave carbon recombination lines (mmCRLs) and existing far-IR [13Cii] hyperfine line observations. Methods. We detect 12 mmCRLs (including α, β, and γ transitions) observed with the IRAM 30m telescope, at ∼25'' angular resolution, toward the H/H2 dissociation front (DF) of the Bar. We also present a mmCRL emission cut across the PDR. Results. These lines trace the C+/C/CO gas transition layer. As the much lower frequency carbon radio recombination lines, mmCRLs arise from neutral PDR gas and not from ionized gas in the adjacent Hii region. This is readily seen from their narrow line profiles (Δv = 2:6 ±0:4 km s-1) and line peak velocities (vLSR = +10:7 ± 0:2 km s-1). Optically thin [13C ii] hyperfine lines and molecular lines - emitted close to the DF by trace species such as reactive ions CO+ and HOC+ - show the same line profiles. We use non-LTE excitation models of [13Cii] and mmCRLs and derive ne = 60-100 cm-3 and Te = 500-600K toward the DF. Conclusions. The inferred electron densities are high, up to an order of magnitude higher than previously thought. They provide a lower limit to the gas thermal pressure at the PDR edge without using molecular tracers.We obtain Pth ≥ (2-4)×10 cm K assuming that the electron abundance is equal to or lower than the gas-phase elemental abundance of carbon. Such elevated thermal pressures leave little room for magnetic pressure support and agree with a scenario in which the PDR photoevaporates., We thank the Spanish MICIU for funding support under grant AYA2017-85111-P and the ERC for support under grant ERC-2013-Syg610256-NANOCOSMOS. A.B.-R. also acknowledges support by the MICIU and FEDER funding under grants ESP2015-65597-C4-1-R and ESP2017-86582-C4-1-R. P.S. and A.G.G.M.T. acknowledge financial support from the Dutch Science Organisation through TOP grant 614.001.351.
Published: 2019
Full Text: View/download PDF

33. Molecular tracers of radiative feedback in Orion (OMC-1). Widespread CH+ (J=1-0), CO (10-9), HCN (6-5), and HCO+ (6-5) emission

Author: David Teyssier, M. G. Santa-Maria, Nuria Marcelino, Javier R. Goicoechea, José Cernicharo, Emeric Bron, S. Cuadrado, Ministerio de Ciencia, Innovación y Universidades (España), and European Commission
Subjects: Infrared, FOS: Physical sciences, Astrophysics, Photodissociation region, ISM: clouds, 01 natural sciences, 12. Responsible consumption, Luminosity, galaxies [Infrared], ISM [Galaxies], 0103 physical sciences, Planetary nebulae: general, 010303 astronomy & astrophysics, Line (formation), Physics, Luminous infrared galaxy, 010308 nuclear & particles physics, Molecular cloud, Astronomy and Astrophysics, Infrared: galaxies, Astrophysics - Astrophysics of Galaxies, Galaxy, 3. Good health, Galaxies: ISM, Stars, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), general [Planetary nebulae], clouds [ISM]
Abstract: 22 pags.; 17 figs., 3 tabs., 3 apps., Young massive stars regulate the physical conditions, ionization, and fate of their natal molecular cloud and surroundings. It is important to find tracers that quantify the stellar feedback processes that take place on different spatial scales. We present -85 arcmin velocity-resolved maps of several submillimeter molecular lines, taken with Herschel/HIFI, toward the closest high-mass star-forming region, the Orion molecular cloud 1 core (OMC-1). The observed rotational lines include probes of warm and dense molecular gas that are difficult, if not impossible, to detect from ground-based telescopes: CH (J = 1-0), CO (J = 10-9), HCO (J = 6-5), HCN (J = 6-5), and CH (N, J = 1, 3/2-1, 1/2). These lines trace an extended but thin layer (AV ≃ 3-6 mag or ~10 cm) of molecular gas at high thermal pressure, P = nH · Tk ≈ 107-109 cm K, associated with the far-ultraviolet (FUV) irradiated surface of OMC-1. The intense FUV radiation field - emerging from massive stars in the Trapezium cluster - heats, compresses, and photoevaporates the cloud edge. It also triggers the formation of specific reactive molecules such as CH+. We find that the CH (J = 1-0) emission spatially correlates with the flux of FUV photons impinging the cloud: G0 from ~10 to ~10. This relationship is supported by constant-pressure photodissociation region (PDR) models in the parameter space P=G ≈ [5 × 10 - 8 × 10] cm K where many observed PDRs seem to lie. The CH+ (J = 1-0) emission also correlates with the extended infrared emission from vibrationally excited H (v ≫ 1), and with that of [C II] 158 μm and CO J = 10-9, all emerging from FUV-irradiated gas. These spatial correlations link the presence of CH+ to the availability of C+ ions and of FUV-pumped H2 (v ≫ 1) molecules.We conclude that the parsec-scale CH emission and narrow-line (δ ≃ 3 km s) mid-J CO emission arises from extended PDR gas and not from fast shocks. PDR line tracers are the smoking g of the stellar feedback from young massive stars. The PDR cloud surface component in OMC-1, with a mass density of 120-240 M⊙pc, represents ~5-10% of the total gas mass; however, it dominates the emitted line luminosity, the average CO J = 10-9 surface luminosity in the mapped region being ~35 times brighter than that of CO J = 2-1. These results provide insights into the source of submillimeter CH+ and mid-J CO emission from distant star-forming galaxies., We thank the Spanish MICIU for funding support under grants AYA2016-75066-C2-1-P and AYA2017-85111-P, and the ERC for support under grant ERC-2013-Syg-610256-NANOCOSMOS.
Published: 2018

34. High-speed molecular cloudlets around the Galactic center’s supermassive black hole

Author: Cinthya N. Herrera, Maryvonne Gerin, José Cernicharo, M. A. Requena-Torres, Javier R. Goicoechea, M. G. Santa-Maria, E. Chapillon, Jérôme Pety, 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 RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), AMOR 2018, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), 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: Physics, Supermassive black hole, Absorption spectroscopy, 010308 nuclear & particles physics, [SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Molecular cloud, Milky Way, Galactic Center, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Astrophysics - Astrophysics of Galaxies, Article, Gravitation, Stars, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Roche limit, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, ComputingMilieux_MISCELLANEOUS
Abstract: We present 1"-resolution ALMA observations of the circumnuclear disk (CND) and the environment around SgrA*. The images unveil the presence of small spatial scale CO (J=3-2) molecular "cloudlets" within the central pc of the Milky Way, moving at high speeds, up to 300 km/s along the line-of-sight. The CO-emitting structures show intricate morphologies: extended and filamentary at high negative-velocities (v_LSR < -150 km/s), more localized and clumpy at extreme positive-velocities (v_LSR > +200 km/s). Based on the pencil-beam CO absorption spectrum toward SgrA* synchrotron emission, we also present evidence for a diffuse gas component producing absorption features at more extreme negative-velocities (v_LSR < -200 km/s). The CND shows a clumpy spatial distribution. Its motion requires a bundle of non-uniformly rotating streams of slightly different inclinations. The inferred gas density peaks are lower than the local Roche limit. This supports that CND molecular cores are transient. We apply the two standard orbit models, spirals vs. ellipses, invoked to explain the kinematics of the ionized gas streamers around SgrA*. The location and velocities of the CO cloudlets are inconsistent with the spiral model, and only two of them are consistent with the Keplerian ellipse model. Most cloudlets, however, show similar velocities that are incompatible with the motions of the ionized streamers or with gas bounded to the central gravity. We speculate that they are leftovers of more massive, tidally disrupted, clouds that fall into the cavity, or that they originate from instabilities in the inner rim of the CND and infall from there. Molecular cloudlets, all together with a mass of several 10 M_Sun, exist around SgrA*. Most of them must be short-lived: photoevaporated by the intense stellar radiation field, blown away by winds from massive stars, or disrupted by strong gravitational shears., Accepted for publication in A&A. 21 pages, 19 figures (includes corrections by language editor)
Published: 2018
Full Text: View/download PDF

35. First Detection of Interstellar S

Author: Asunción, Fuente, Javier R, Goicoechea, Jerome, Pety, Romane, Le Gal, Rafael, Martín-Doménech, Pierre, Gratier, Viviana, Guzmán, Evelyne, Roueff, Jean Christophe, Loison, Guillermo M, Muñoz Caro, Valentine, Wakelam, Maryvonne, Gerin, Pablo, Riviere-Marichalar, and Thomas, Vidal
Subjects: Article
Abstract: We present the first detection of gas phase S2H in the Horsehead, a moderately UV-irradiated nebula. This confirms the presence of doubly sulfuretted species in the interstellar medium and opens a new challenge for sulfur chemistry. The observed S2H abundance is ~5×10−11, only a factor 4-6 lower than that of the widespread H2S molecule. H2S and S2H are efficiently formed on the UV-irradiated icy grain mantles. We performed ice irradiation experiments to determine the H2S and S2H photodesorption yields. The obtained values are ~1.2×10−3 and
Published: 2018

36. Using radio astronomical receivers for molecular spectroscopic characterization in astrochemical laboratory simulations: A proof of concept

Author: J.A. López, Lidia Martínez, D. Teyssier, Ramón J. Peláez, J. A. Martín-Gago, J. Gomez-Gonzalez, Elena Jiménez, Marcelino Agúndez, Koen Lauwaet, Belén Alemán, E. Moreno, Kremena Makasheva, Christine Joblin, Javier R. Goicoechea, A. Díaz-Pulido, José Luis Doménech, José L. Alonso, José Cernicharo, Gonzalo Santoro, Juan Daniel Gallego, P. de Vicente, M. Castellanos, J. M. Hernandez, Víctor J. Herrero, F. Tercero, Juan R. Pardo, Jesús Manuel Sobrado, J. A. López-Pérez, Isabel Tanarro, Spanish National Research Council (CSIC), Inst Chem, QUIREMA, Matériaux et Procédés Plasmas (LAPLACE-MPP), LAboratoire PLasma et Conversion d'Energie (LAPLACE), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, 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), European Research Council, European Commission, Ministerio de Economía y Competitividad (España), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)
Subjects: Methods: laboratory: molecular, 010504 meteorology & atmospheric sciences, laboratory: molecular [Methods], Impedance matching, Instrumentation: spectrographs, Astrophysics, 01 natural sciences, 7. Clean energy, Article, Radio telescope, [SPI]Engineering Sciences [physics], Optics, Data acquisition, 0103 physical sciences, spectrographs [Instrumentation], Spectroscopy, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Electron ionization, Astrochemistry, 0105 earth and related environmental sciences, Physics, Spectrometer, Molecular data, business.industry, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy and Astrophysics, Plasma, Chemical reactor, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Astrophysics - Instrumentation and Methods for Astrophysics, business
Abstract: I. Tanarro et al. -- 16 pags., 18 figs., app., We present a proof of concept on the coupling of radio astronomical receivers and spectrometers with chemical reactors and the performances of the resulting setup for spectroscopy and chemical simulations in laboratory astrophysics. Several experiments including cold plasma generation and UV photochemistry were performed in a 40 cm long gas cell placed in the beam path of the Aries 40 m radio telescope receivers operating in the 41–49 GHz frequency range interfaced with fast Fourier transform spectrometers providing 2 GHz bandwidth and 38 kHz resolution. The impedance matching of the cell windows has been studied using di erent materials. The choice of the material and its thickness was critical to obtain a sensitivity identical to that of standard radio astronomical observations. Spectroscopic signals arising from very low partial pressures of CH3OH, CH3CH2OH, HCOOH, OCS, CS, SO2 (, The research leading to these results has received funding from the European Research Council under the European Union’s Seventh Framework Programme (FP/2007-2013)/ERC-SyG-2013 Grant Agreement No. 610256 NANOCOSMOS and from spanish MINECO CSD2009-00038 (ASTROMOL) under the Consolider-Ingenio Program. We also thank spanish MINECO for funding under grants AYA2012-32032, AYA2016-75066-C2-1-P, FIS2013-48087-C2-1-P, FIS2016-77726-C3-1-P, FIS2016-77578-R, MAT2014- 54231-C4-1-P.
Published: 2018
Full Text: View/download PDF

37. High-velocity hot CO emission close to Sgr A: Herschel/HIFI submillimeter spectral survey toward Sgr A

Author: M. G. Santa-Maria, Jérôme Pety, D. Teyssier, Javier R. Goicoechea, Maryvonne Gerin, and José Cernicharo
Subjects: Physics, Supermassive black hole, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Radiation, Astrophysics - Astrophysics of Galaxies, 01 natural sciences, law.invention, Telescope, Stars, 13. Climate action, Space and Planetary Science, law, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Radiative transfer, Irradiation, 010306 general physics, 010303 astronomy & astrophysics, Excitation, Line (formation)
Abstract: The properties of molecular gas, the fuel that forms stars, inside the cavity of the circumnuclear disk (CND) are not well constrained. We present results of a velocity-resolved submillimeter scan (~480 to 1250 GHz}) and [CII]158um line observations carried out with Herschel/HIFI toward Sgr A*; these results are complemented by a ~2'x2' CO (J=3-2) map taken with the IRAM 30 m telescope at ~7'' resolution. We report the presence of high positive-velocity emission (up to about +300 km/s) detected in the wings of CO J=5-4 to 10-9 lines. This wing component is also seen in H2O (1_{1,0}-1_{0,1}) a tracer of hot molecular gas; in [CII]158um, an unambiguous tracer of UV radiation; but not in [CI]492,806 GHz. This first measurement of the high-velocity CO rotational ladder toward Sgr A* adds more evidence that hot molecular gas exists inside the cavity of the CND, relatively close to the supermassive black hole (< 1 pc). Observed by ALMA, this velocity range appears as a collection of CO (J=3-2) cloudlets lying in a very harsh environment that is pervaded by intense UV radiation fields, shocks, and affected by strong gravitational shears. We constrain the physical conditions of the high positive-velocity CO gas component by comparing with non-LTE excitation and radiative transfer models. We infer T_k~400 K to 2000 K for n_H~(0.2-1.0)x10^5 cm^-3. These results point toward the important role of stellar UV radiation, but we show that radiative heating alone cannot explain the excitation of this ~10-60 M_Sun component of hot molecular gas inside the central cavity. Instead, strongly irradiated shocks are promising candidates., Accepted for publication in A&A Letters ( this v2 includes corrections by language editor)
Published: 2018
Full Text: View/download PDF

38. Gas phase Elemental abundances in Molecular cloudS (GEMS) I. The prototypical dark cloud TMC 1

Author: Jean-Christophe Loison, Valerio Lattanzi, Nuria Marcelino, Stéphanie Cazaux, Maryvonne Gerin, Rafael Bachiller, Javier R. Goicoechea, S. P. Treviño-Morales, Paola Caselli, T. Alonso-Albi, C. Kramer, Santiago García-Burillo, Benoît Commerçon, Barbara M. Giuliano, Rafael Martín-Doménech, Belén Tercero, M. Y. Ballester, D. G. Navarro, Alvaro Hacar, Derek Ward-Thompson, Johanna Malinen, Jaime E. Pineda, Asunción Fuente, G. Muñoz-Caro, Izaskun Jiménez-Serra, Pablo Riviere-Marichalar, Jason M. Kirk, Octavio Roncero, Mario Tafalla, E. Roueff, Rachel Friesen, Thomas H. G. Vidal, Pierre Gratier, INAF - Osservatorio Astrofisico di Arcetri (OAA), Istituto Nazionale di Astrofisica (INAF), Observatoire de Paris, Université Paris sciences et lettres (PSL), 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), AMOR 2019, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatorio Astronomico Nacional, Madrid, 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), Laboratoire de Radioastronomie, Laboratoire de Radioastronomie (LRA), 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)-Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Queen Mary University of London (QMUL), Institut des Sciences Moléculaires (ISM), Université Montesquieu - Bordeaux 4-Université Sciences et Technologies - Bordeaux 1 (UB)-École Nationale Supérieure de Chimie et de Physique de Bordeaux (ENSCPB)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), INAF - Osservatorio Astronomico di Bologna (OABO), Laboratoire de Radiopathologie (LRP), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Institut National de la Santé et de la Recherche Médicale (INSERM), foreign laboratories (FL), CERN [Genève], Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Jeremiah Horrocks Institute for Mathematics, Physics and Astronomy [Preston], University of Central Lancashire [Preston] (UCLAN), Instituto de Radio Astronomía Milimétrica, Departamento de Astrofisica [Madrid], Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Spanish National Research Council (CSIC), Agencia Estatal de Investigación (España), Ministerio de Ciencia, Innovación y Universidades (España), European Commission, Ministerio de Economía y Competitividad (España), Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Laboratoire Univers et Théories (LUTH (UMR_8102)), PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Observatorio Astronómico Nacional (OAN), oan, Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris)-Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), Observatorio Astronomico Nacional [Madrid] (OAN), Instituto Geografico Nacional (IGN), Ctr Astrobiol CSIC INTA, Lab Astofis Mol, Madrid 28850, Université Montesquieu - Bordeaux 4-Université Sciences et Technologies - Bordeaux 1-École Nationale Supérieure de Chimie et de Physique de Bordeaux (ENSCPB)-Centre National de la Recherche Scientifique (CNRS), Université Paris Diderot - Paris 7 (UPD7)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de la Santé et de la Recherche Médicale (INSERM), Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Department of Physics, 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), 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)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), and Université Montesquieu - Bordeaux 4-Université Sciences et Technologies - Bordeaux 1-École Nationale Supérieure de Chimie et de Physique de Bordeaux (ENSCPB)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)
Subjects: [SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Astrophysics, 01 natural sciences, ISM: abundances, Protein filament, Ionization, Phase (matter), Astronomy, Astrophysics and Cosmology, low-mass [stars], TAURUS, 010303 astronomy & astrophysics, Astrochemistry, abundances [ISM], Physics, [PHYS]Physics [physics], astrochemistry, DIFFUSE CLOUDS, ISM: molecules, Meteorology and Atmospheric Sciences, IONIZATION, ROTATIONAL-EXCITATION, Stars: formation, SULFUR, FOS: Physical sciences, Article, IRAM 30m telescope, STAR-FORMATION, CO DEPLETION, 0103 physical sciences, Stars: low-mass, POTENTIAL-ENERGY SURFACE, molecules [ISM], ISM: kinematics and dynamics, formation [stars], 010308 nuclear & particles physics, Star formation, COMPARATIVE CHEMISTRY, Molecular cloud, Astronomy and Astrophysics, 115 Astronomy, Space science, Astrophysics - Astrophysics of Galaxies, kinematics and dynamics [ISM], Geochemistry, INTERSTELLAR GAS, Cover (topology), 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: 26 pags., 7 figs., 2 tabs., 2 apps., GEMS is an IRAM 30 m Large Program whose aim is determining the elemental depletions and the ionization fraction in a set of prototypical star-forming regions. This paper presents the first results from the prototypical dark cloud Taurus molecular cloud (TMC) 1. Extensive millimeter observations have been carried out with the IRAM 30 m telescope (3 and 2 mm) and the 40 m Yebes telescope (1.3 cm and 7 mm) to determine the fractional abundances of CO, HCO, HCN, CS, SO, HCS, and N H in three cuts which intersect the dense filament at the well-known positions TMC 1-CP, TMC 1-NH3, and TMC 1-C, covering a visual extinction range from A ~ 3 to ~20 mag. Two phases with differentiated chemistry can be distinguished: (i) the translucent envelope with molecular hydrogen densities of 1-5 × 10 cm; and (ii) the dense phase, located at A > 10 mag, with molecular hydrogen densities >10 cm. Observations and modeling show that the gas phase abundances of C and O progressively decrease along the C/C/CO transition zone (A~ 3 mag) where C/H ~ 8 × 10 and C/O ~ 0.8-1, until the beginning of the dense phase at A ~ 10 mag. This is consistent with the grain temperatures being below the CO evaporation temperature in this region. In the case of sulfur, a strong depletion should occur before the translucent phase where we estimate an S/ H ~ (0.4-2.2) × 10, an abundance ~7-40 times lower than the solar value. A second strong depletion must be present during the formation of the thick icy mantles to achieve the values of S/H measured in the dense cold cores (S H ~ 8 × 10) . Based on our chemical modeling, we constrain the value of ζ to ~(0.5-1.8) × 10 s in the translucent cloud., We thank the Spanish MINECO for funding support from AYA2016-75066-C2-1/2-P, and the ERC under ERC-2013-SyG, G. A. 610256 NANOCOSMOS. JM acknowledges the support of ERC-2015-STG No. 679852 RADFEEDBACK. SPTM acknowledges to the European Union’s Horizon 2020 research and innovation program for funding support given under grant agreement No 639459 (PROMISE). RMD acknowledges support provided by an award from the Simons Foundation (SCOL#321183, KO). GMC acknowedges funding support fromAYA2017-85322-R. MT acknowledges partial support from project AYA2016-79006-P.”
Published: 2018
Full Text: View/download PDF

39. Compression and ablation of the photo-irradiated molecular cloud the Orion Bar

Author: Jérôme Pety, Javier R. Goicoechea, P. Pilleri, S. Cuadrado, E. Chapillon, Maryvonne Gerin, Christine Joblin, Nuria Marcelino, José Cernicharo, Asunción Fuente, Ministerio de Ciencia e Innovación (España), Ministerio de Economía y Competitividad (España), Centre National de la Recherche Scientifique (France), and European Research Council
Subjects: Physics, Multidisciplinary, 010308 nuclear & particles physics, Molecular cloud, Astronomical unit, Non-equilibrium thermodynamics, Astrophysics, Space physics, 01 natural sciences, Article, Dissociation (chemistry), Interstellar medium, Stars, 13. Climate action, Ionization, 0103 physical sciences, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics
Abstract: The Orion Bar is the archetypal edge-on molecular cloud surface illuminated by strong ultraviolet radiation from nearby massive stars. Our relative closeness to the Orion nebula (about 1,350 light years away from Earth) means that we can study the effects of stellar feedback on the parental cloud in detail. Visible-light observations of the Orion Bar show that the transition between the hot ionized gas and the warm neutral atomic gas (the ionization front) is spatially well separated from the transition between atomic and molecular gas (the dissociation front), by about 15 arcseconds or 6,200 astronomical units (one astronomical unit is the Earth-Sun distance). Static equilibrium models used to interpret previous far-infrared and radio observations of the neutral gas in the Orion Bar (typically at 10-20 arcsecond resolution) predict an inhomogeneous cloud structure comprised of dense clumps embedded in a lower-density extended gas component. Here we report one-arcsecond-resolution millimetre-wave images that allow us to resolve the molecular cloud surface. In contrast to stationary model predictions, there is no appreciable offset between the peak of the H vibrational emission (delineating the H/H transition) and the edge of the observed CO and HCO emission. This implies that the H/H 2 and C/C/CO transition zones are very close. We find a fragmented ridge of high-density substructures, photoablative gas flows and instabilities at the molecular cloud surface. The results suggest that the cloud edge has been compressed by a high-pressure wave that is moving into the molecular cloud, demonstrating that dynamical and non-equilibrium effects are important for the cloud evolution., We thank the ERC for support under grant ERC-2013-Syg-610256-NANOCOSMOS. We also thank MINECO, Spain, for funding support under grants CSD2009-00038 and AYA2012-32032. This work was in part supported by the French CNRS programme ‘Physique et Chimie du Milieu Interstellaire’.
Published: 2016
Full Text: View/download PDF

40. Complex organic molecules in strongly UV-irradiated gas

Author: Javier R. Goicoechea, S. Cuadrado, José Cernicharo, Asunción Fuente, Belén Tercero, Jérôme Pety, European Research Council, Ministerio de Economía y Competitividad (España), Ministerio de Ciencia e Innovación (España), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Instituto de Ciencia de Materiales de Madrid (ICMM), 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), and École normale supérieure - Paris (ENS Paris)
Subjects: Astrochemistry, Population, Analytical chemistry, FOS: Physical sciences, Astrophysics, Photodissociation region, Surveys, 01 natural sciences, Dissociation (chemistry), ISM: abundances, Article, 0103 physical sciences, Molecule, 010306 general physics, Spectroscopy, education, 010303 astronomy & astrophysics, molecules [ISM], ComputingMilieux_MISCELLANEOUS, Physics, abundances [ISM], [PHYS]Physics [physics], education.field_of_study, Molecular cloud, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, ISM: molecules, Photon-dominated region (PDR), 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Excitation
Abstract: We investigate the presence of complex organic molecules (COMs) in strongly UV-irradiated interstellar molecular gas. We have carried out a complete millimetre (mm) line survey using the IRAM 30 m telescope towards the edge of the Orion Bar photodissociation region (PDR), close to the H dissociation front, a position irradiated by a very intense far-UV (FUV) radiation field. These observations have been complemented with 8.5′′ resolution maps of the HCO Ja,K = 5 → 4 and CO J = 3 → 2 emission at 0.9 mm. Despite being a harsh environment, we detect more than 250 lines from COMs and related precursors: HCO, CHOH, HCO, HCCO, CHCHO, HCS, HCOOH, CHCN, CHNH, HNCO, H CO, and HCN (in decreasing order of abundance). For each species, the large number of detected lines allowed us to accurately constrain their rotational temperatures (T) and column densities (N). Owing to subthermal excitation and intricate spectroscopy of some COMs (symmetric-and asymmetric-Top molecules such as CHCN and HCO, respectively), a correct determination of N and T requires building rotational population diagrams of their rotational ladders separately. The inferred column densities are in the 10-10 cm range. We also provide accurate upper limit abundances for chemically related molecules that might have been expected, but are not conclusively detected at the edge of the PDR (HDCO, CHO, CHNC, CHCCH, CHOCH, HCOOCH, CHCHOH, CHCHCN, and CHCHCN). A non-Thermodynamic equilibrium excitation analysis for molecules with known collisional rate coefficients suggests that some COMs arise from different PDR layers but we cannot resolve them spatially. In particular, HCO and CHCN survive in the extended gas directly exposed to the strong FUV flux (T = 150-250 K and Tâ60 K), whereas CHOH only arises from denser and cooler gas clumps in the more shielded PDR interior (T = 40-50 K). The non-detection of HDCO towards the PDR edge is consistent with the minor role of pure gas-phase deuteration at very high temperatures. We find a HCO/HCO/CHOH â1/5/3 abundance ratio. These ratios are different from those inferred in hot cores and shocks. Taking into account the elevated gas and dust temperatures at the edge of the Bar (mostly mantle-free grains), we suggest the following scenarios for the formation of COMs: (i) hot gas-phase reactions not included in current models; (ii) warm grain-surface chemistry; or (iii) the PDR dynamics is such that COMs or precursors formed in cold icy grains deeper inside the molecular cloud desorb and advect into the PDR., This work has been partially funded by MINECO grants (CSD2009-00038 and AYA2012-32032). We thank the ERC for support under grant ERC-2013-Syg-610256-NANOCOSMOS.
Published: 2017
Full Text: View/download PDF

41. Clustering the Orion B giant molecular cloud based on its molecular emission

Author: Nicolas Peretto, Pierre Gratier, Javier R. Goicoechea, Karin I. Öberg, François Levrier, Sébastien Bardeau, Chloé Daudon, Harvey S. Liszt, Maryvonne Gerin, Emeric Bron, Jérôme Pety, Albrecht Sievers, Viviana V. Guzmán, Pascal Tremblin, Jan H. Orkisz, Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), 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), Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), AMOR 2018, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Joint ALMA Observatory (JAO), European Southern Observatory (ESO)-National Radio Astronomy Observatory (NRAO), National Radio Astronomy Observatory (NRAO), Harvard-Smithsonian Center for Astrophysics (CfA), Smithsonian Institution-Harvard University [Cambridge], School of Physics and Astronomy [Cardiff], Cardiff University, Maison de la Simulation (MDLS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut National de Recherche en Informatique et en Automatique (Inria)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), LERMA Cergy (LERMA), 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), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Université Grenoble Alpes (UGA), Harvard University-Smithsonian Institution, and European Project: 610256,EC:FP7:ERC,ERC-2013-SyG,NANOCOSMOS(2014)
Subjects: medicine.medical_specialty, ISM: individual objects: Orion B, Astrochemistry, ISM: structure, FOS: Physical sciences, Context (language use), 02 engineering and technology, Astrophysics, 01 natural sciences, ISM: clouds, Article, 0103 physical sciences, 0202 electrical engineering, electronic engineering, information engineering, medicine, Radiative transfer, Cluster (physics), Cluster analysis, Instrumentation and Methods for Astrophysics (astro-ph.IM), 010303 astronomy & astrophysics, QB, Line (formation), Physics, methods: statistical, astrochemistry, Molecular cloud, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, ISM: molecules, Spectral imaging, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 020201 artificial intelligence & image processing, [SDU.ASTR.GA]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA], Astrophysics - Instrumentation and Methods for Astrophysics
Abstract: Previous attempts at segmenting molecular line maps of molecular clouds have focused on using position-position-velocity data cubes of a single line to separate the spatial components of the cloud. In contrast, wide field spectral imaging with large spectral bandwidth in the (sub)mm domain now allows to combine multiple molecular tracers to understand the different physical and chemical phases that constitute giant molecular clouds. We aim at using multiple tracers (sensitive to different physical processes) to segment a molecular cloud into physically/chemically similar regions (rather than spatially connected components). We use a machine learning clustering method (the Meanshift algorithm) to cluster pixels with similar molecular emission, ignoring spatial information. Simple radiative transfer models are used to interpret the astrophysical information uncovered by the clustering. A clustering analysis based only on the J=1-0 lines of 12CO, 13CO and C18O reveals distinct density/column density regimes (nH~100, 500, and >1000 cm-3), closely related to the usual definitions of diffuse, translucent and high-column-density regions. Adding two UV-sensitive tracers, the (1-0) lines of HCO+ and CN, allows us to distinguish two clearly distinct chemical regimes, characteristic of UV-illuminated and UV-shielded gas. The UV-illuminated regime shows overbright HCO+ and CN emission, which we relate to photochemical enrichment. We also find a tail of high CN/HCO+ intensity ratio in UV-illuminated regions. Finer distinctions in density classes (nH~7E3, and 4E4 cm-3) for the densest regions are also identified, likely related to the higher critical density of the CN and HCO+ (1-0) lines. The association of simultaneous multi-line, wide-field mapping and powerful machine learning methods such as the Meanshift algorithm reveals how to decode the complex information available in molecular tracers., Accepted for publication in A&A. 26 pages and 23 figures. The associated data products will soon be available at http://www.iram.fr/~pety/ORION-B
Published: 2017
Full Text: View/download PDF

42. Herschel survey and modelling of externally-illuminated photoevaporating protoplanetary disks

Author: Inga Kamp, Christine Joblin, Javier R. Goicoechea, Jason Champion, Antoine Gusdorf, Olivier Berné, Franck Petit, S. Vicente, 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), Kapteyn Astronomical Institute [Groningen], University of Groningen [Groningen], 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), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), 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), École normale supérieure - Paris (ENS-PSL), and Astronomy
Subjects: Photon, 010504 meteorology & atmospheric sciences, Evaporation, CARINA NEBULA, FOS: Physical sciences, Astrophysics, Photodissociation region, 01 natural sciences, Article, methods: numerical, photon-dominated region, Far infrared, Speed of sound, YOUNG STARS, CIRCUMSTELLAR DISKS, 0103 physical sciences, infrared: planetary systems, EXTREME-ULTRAVIOLET, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Line (formation), Envelope (waves), Earth and Planetary Astrophysics (astro-ph.EP), Physics, PHOTODISSOCIATION REGION, protoplanetary disks, FAR-ULTRAVIOLET RADIATION, Astronomy and Astrophysics, Photoevaporation, PROTOSTELLAR DISKS, 13. Climate action, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, methods: observational, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], EMISSION, ORION NEBULA, MASSIVE STARS, Astrophysics - Earth and Planetary Astrophysics
Abstract: Protoplanetary disks undergo substantial mass-loss by photoevaporation, a mechanism which is crucial to their dynamical evolution. However, the processes regulating the gas energetics have not been well constrained by observations so far. We aim at studying the processes involved in disk photoevaporation when it is driven by far-UV photons. We present a unique Herschel survey and new ALMA observations of four externally-illuminated photoevaporating disks (a.k.a. proplyds). For the analysis of these data, we developed a 1D model of the photodissociation region (PDR) of a proplyd, based on the Meudon PDR code and computed the far infrared line emission. We successfully reproduce most of the observations and derive key physical parameters, i.e. densities at the disk surface of about $10^{6}$ cm$^{-3}$ and local gas temperatures of about 1000 K. Our modelling suggests that all studied disks are found in a transitional regime resulting from the interplay between several heating and cooling processes that we identify. These differ from those dominating in classical PDRs, i.e. grain photo-electric effect and cooling by [OI] and [CII] FIR lines. This energetic regime is associated to an equilibrium dynamical point of the photoevaporation flow: the mass-loss rate is self-regulated to set the envelope column density at a value that maintains the temperature at the disk surface around 1000 K. From our best-fit models, we estimate mass-loss rates - of the order of $10^{-7}$ $\mathrm{M}_\odot$/yr - that are in agreement with earlier spectroscopic observation of ionised gas tracers. This holds only if we assume an evaporation flow launched from the disk surface at sound speed (supercritical regime). We have identified the energetic regime regulating FUV-photoevaporation in proplyds. This regime could be implemented into models of the dynamical evolution of protoplanetary disks., 17 pages (6 more with appendices), 11 figures, accepted for publication in A&A
Published: 2017
Full Text: View/download PDF

43. Spatially resolved images of reactive ions in the Orion Bar

Author: Javier R. Goicoechea, Jérôme Pety, John H. Black, Emeric Bron, Maryvonne Gerin, José Cernicharo, Asunción Fuente, S. Cuadrado, Edwige Chapillon, 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 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), Onsala Space Observatory (OSO), Chalmers University of Technology [Göteborg], Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), AMOR 2017, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Ministerio de Economía y Competitividad (España), Ministerio de Ciencia e Innovación (España), European Research Council, and École normale supérieure - Paris (ENS-PSL)
Subjects: [SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Line: identification, (ISM:) photon-dominated region (PDR), Inelastic collision, Analytical chemistry, FOS: Physical sciences, Astrophysics, Photodissociation region, 7. Clean energy, 01 natural sciences, ISM: clouds, Article, Ion, 0103 physical sciences, Radiative transfer, identification [Line], 010306 general physics, 010303 astronomy & astrophysics, Astrochemistry, Physics, Molecular cloud, ) photon-dominated region (PDR) [(ISM], Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, 13. Climate action, Space and Planetary Science, Excited state, Astrophysics of Galaxies (astro-ph.GA), clouds [ISM], Excitation, Bar (unit)
Abstract: We report high angular resolution (4.9" x 3.0") images of reactive ions SH+, HOC+, and SO+ toward the Orion Bar photodissociation region (PDR). We used ALMA-ACA to map several rotational lines at 0.8 mm, complemented with multi-line observations obtained with the IRAM 30m telescope. The SH+ and HOC+ emission is restricted to a narrow layer of 2"- to 10"-width (~800 to 4000 AU depending on the assumed PDR geometry) that follows the vibrationally excited H2^* emission. Both ions efficiently form very close to the H/H2 transition zone, at a depth of A_V < 1 mag into the neutral cloud, where abundant C+, S+, and H2^* coexist. SO+ peaks slightly deeper into the cloud. The observed ions have low rotational temperatures (T_rot~10-30 K << T_k) and narrow line-widths (~2-3 km/s), a factor of ~2 narrower that those of the lighter reactive ion CH+. This is consistent with the higher reactivity and faster radiative pumping rates of CH+ compared to the heavier ions, which are driven relatively faster toward smaller velocity dispersion by elastic collisions and toward lower T_rot by inelastic collisions. We estimate column densities and average physical conditions from a non-LTE excitation model (n(H2)~10^5-10^6 cm^-3, n(e^-)~10 cm^-3, and T_k~200 K). Regardless of the excitation details, SH+ and HOC+ clearly trace the most exposed layers of the UV-irradiated molecular cloud surface, whereas SO+ arises from slightly more shielded layers., Accepted for publication in A&A letters (4 figures and 5 tables with Appendices)
Published: 2017
Full Text: View/download PDF

44. First detection of interstellar S2H

Author: E. Roueff, Jérôme Pety, Javier R. Goicoechea, Pablo Riviere-Marichalar, Thomas H. G. Vidal, Valentine Wakelam, Romane Le Gal, Guillermo M. Muñoz Caro, Maryvonne Gerin, Viviana V. Guzmán, Rafael Martín-Doménech, Asunción Fuente, Pierre Gratier, Jean-Christophe Loison, Observatorio Astronomico Nacional, Madrid, Consejo Superior de Investigaciones Científicas [Spain] (CSIC), Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), 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), AMOR 2017, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Joint ALMA Observatory (JAO), European Southern Observatory (ESO)-National Radio Astronomy Observatory (NRAO), 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), European Space Astronomy Centre (ESAC), European Space Agency (ESA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), 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]), National Radio Astronomy Observatory (NRAO)-European Southern Observatory (ESO), 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), European Research Council, Ministerio de Economía y Competitividad (España), Centre National de la Recherche Scientifique (France), Centre National D'Etudes Spatiales (France), Institut national des sciences de l'Univers (France), École normale supérieure - Paris (ENS-PSL), and Agence Spatiale Européenne = European Space Agency (ESA)
Subjects: Astrochemistry, Abundance (chemistry), [SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Analytical chemistry, FOS: Physical sciences, 01 natural sciences, ISM: abundances, Ion, Desorption, 0103 physical sciences, Molecule, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), molecules [ISM], abundances [ISM], Physics, Nebula, 010304 chemical physics, ISM: individual objects (Horsehead), Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, ISM: molecules, Methods: laboratory: solid state, Photon-dominated region (PDR), Interstellar medium, laboratory: solid state [Methods], Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Yield (chemistry), individual objects (Horsehead) [ISM]
Abstract: We present the first detection of gas-phase SH in the Horsehead, a moderately UV-irradiated nebula. This confirms the presence of doubly sulfuretted species in the interstellar medium and opens a new challenge for sulfur chemistry. The observed SH abundance is ∼5 × 10, only a factor of 4-6 lower than that of the widespread HS molecule. HS and SH are efficiently formed on the UV-irradiated icy grain mantles. We performed ice irradiation experiments to determine the HS and SH photodesorption yields. The obtained values are ∼1.2 × 10 and, V.W.'s research is funded by an ERC Starting Grant (3DICE, grant agreement 336474). We thank the Spanish MINECO for funding support from AYA2016-75066-C2-1/2-P, AYA2012-32032 and ERC under ERC-2013-SyG, G. A. 610256 NANOCOSMOS. This work was supported by the Programme National >Physique et Chimie du Milieu Interstellaire> (PCMI) of CNRS/INSU with INC/INP co-funded by CEA and CNES.
Published: 2017
Full Text: View/download PDF

45. Dissecting the molecular structure of the Orion B cloud: Insight from Principal Component Analysis

Author: Nicolas Peretto, Emeric Bron, Franck Le Petit, Karin I. Öberg, Evelyne Roueff, Viviana V. Guzmán, Pascal Tremblin, Sébastien Bardeau, Albrech Sievers, Javier R. Goicoechea, Jérôme Pety, Jan H. Orkisz, Maryvonne Gerin, Harvey S. Liszt, Pierre Gratier, AMOR 2017, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'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), Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), Harvard-Smithsonian Center for Astrophysics (CfA), Harvard University [Cambridge]-Smithsonian Institution, Université Grenoble Alpes (UGA), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), National Radio Astronomy Observatory (NRAO), School of Physics and Astronomy [Cardiff], Cardiff University, Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Instituto de RadioAstronomía Milimétrica (IRAM), University of Exeter, Maison de la Simulation (MDLS), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Université Paris-Sud - Paris 11 (UP11)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Centre National de la Recherche Scientifique (France), Centre National D'Etudes Spatiales (France), European Research Council, Institut national des sciences de l'Univers (France), 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), Smithsonian Institution-Harvard University [Cambridge], Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), École normale supérieure - Paris (ENS-PSL), Harvard University-Smithsonian Institution, 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), and Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut National de Recherche en Informatique et en Automatique (Inria)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)
Subjects: Brightness, ISM: individual objects: Orion B, statistical [Methods], Astrochemistry, Field (physics), [SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], FOS: Physical sciences, Context (language use), Astrophysics, 01 natural sciences, ISM: clouds, Spectral line, photon-dominated region (PDR), 0103 physical sciences, Radiative transfer, 010303 astronomy & astrophysics, molecules [ISM], Astrophysics::Galaxy Astrophysics, QB, Physics, methods: statistical, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], 010308 nuclear & particles physics, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, ISM: molecules, Interstellar medium, individual objects: Orion B [ISM], Photon-dominated region (PDR), Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Principal component analysis, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], clouds [ISM]
Abstract: [Context] The combination of wideband receivers and spectrometers currently available in (sub-)millimeter observatories deliver wide-field hyperspectral imaging of the interstellar medium. Tens of spectral lines can be observed over degree wide fields in about 50 h. This wealth of data calls for restating the physical questions about the interstellar medium in statistical terms., [Aims] We aim to gain information on the physical structure of the interstellar medium from a statistical analysis of many lines from different species over a large field of view, without requiring detailed radiative transfer or astrochemical modeling., [Methods] We coupled a non-linear rescaling of the data with one of the simplest multivariate analysis methods, namely the principal component analysis, to decompose the observed signal into components that we interpret first qualitatively and then quantitatively based on our deep knowledge of the observed region and of the astrochemistry at play., [Results] We identify three principal components, linear compositions of line brightness temperatures, that are correlated at various levels with the column density, the volume density and the UV radiation field., [Conclusions] When sampling a sufficiently diverse mixture of physical parameters, it is possible to decompose the molecular emission in order to gain physical insight on the observed interstellar medium. This opens a new avenue for future studies of the interstellar medium., This work was supported by the French program Physique et Chimie du Milieu Interstellaire (PCMI) funded by the Conseil National de la Recherche Scientifique (CNRS) and Centre National d’Études Spatiales (CNES). P.G. thanks ERC starting grant (3DICE, grant agreement 336474) for funding during this work. P.G.’s current postdoctoral position is funded by the INSU/CNRS.
Published: 2017
Full Text: View/download PDF

46. Probing the cold dust emission in the AB Aur Disk: a dust trap in a decaying vortex?

Author: Rafael Bachiller, Javier R. Goicoechea, Roberto Neri, Clément Baruteau, Olivier Berné, Andres Carmona, Asunción Fuente, Marcelino Agúndez, José Cernicharo, Ministerio de Economía y Competitividad (España), European Research Council, Observatorio Astronomico Nacional, Madrid, 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), Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superior de Investigaciones Científicas [Spain] (CSIC), 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), 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), Centre d'étude spatiale des rayonnements (CESR), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), 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), 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 de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), and Université Fédérale Toulouse Midi-Pyrénées
Subjects: Protoplanetary disks, 010504 meteorology & atmospheric sciences, Formation [Planets and satellites], FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, Trapping, Astrophysics, stars: individual: AB Auriga, 01 natural sciences, circumstellar matter, Article, individual (AB Auriga) [Stars], Planet, 0103 physical sciences, planets and satellites: formation, Stars: individual (AB Auriga), 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Earth and Planetary Astrophysics (astro-ph.EP), Physics, stars: variables: T Tauri, Turbulent diffusion, planet─disk interactions, protoplanetary disks, Herbig Ae/Be, Planet–disk interactions, Astronomy and Astrophysics, Circumstellar matter, Vortex, Wavelength, Stars, 13. Climate action, Space and Planetary Science, Stars: variables: T Tauri, Herbig Ae/Be, Terrestrial planet, Astrophysics::Earth and Planetary Astrophysics, Protoplanet, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], variables: T Tauri, Herbig Ae/Be [Stars], Astrophysics - Earth and Planetary Astrophysics
Abstract: One serious challenge for planet formation is the rapid inward drift of pebble-sized dust particles in protoplanetary disks. Dust trapping at local maxima in the disk gas pressure has received much theoretical attention but still lacks observational support. The cold dust emission in the AB Aur disk forms an asymmetric ring at a radius of about 120 au, which is suggestive of dust trapping in a gas vortex. We present high spatial resolution (0.″58 × 0.″78 ≈ 80 × 110 au) NOEMA observations of the 1.12 mm and 2.22 mm dust continuum emission from the AB Aur disk. Significant azimuthal variations of the flux ratio at both wavelengths indicate a size segregation of the large dust particles along the ring. Our continuum images also show that the intensity variations along the ring are smaller at 2.22 mm than at 1.12 mm, contrary to what dust trapping models with a gas vortex have predicted. Our two-fluid (gas+dust) hydrodynamical simulations demonstrate that this feature is well explained if the gas vortex has started to decay due to turbulent diffusion, and dust particles are thus losing the azimuthal trapping on different timescales depending on their size. The comparison between our observations and simulations allows us to constrain the size distribution and the total mass of solid particles in the ring, which we find to be of the order of 30 Earth masses, enough to form future rocky planets., We thank the referee for a helpful and thorough report. We thank the Spanish MINECO for funding support from AYA2016-75066-C2-1/2-P, AYA2016-79006-P, AYA2012-32032, FIS2012-32096, and ERC under ERC-2013-SyG, G. A. 610256 NANOCOSMOS.
Published: 2017
Full Text: View/download PDF

47. Turbulence and star formation efficiency in molecular clouds: solenoidal versus compressive motions in Orion B

Author: Javier R. Goicoechea, Nicolas Peretto, Maryvonne Gerin, Karin I. Öberg, Sébastien Bardeau, Viviana V. Guzmán, Pascal Tremblin, Evelyne Roueff, Harvey S. Liszt, Franck Le Petit, Pierre Gratier, François Levrier, Albrecht Sievers, Jan H. Orkisz, Jérôme Pety, Emeric Bron, 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), Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), Harvard-Smithsonian Center for Astrophysics (CfA), Harvard University-Smithsonian Institution, Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), AMOR 2017, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), National Radio Astronomy Observatory (NRAO), School of Physics and Astronomy [Cardiff], Cardiff University, 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), Instituto de RadioAstronomía Milimétrica (IRAM), University of Exeter, Maison de la Simulation (MDLS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut National de Recherche en Informatique et en Automatique (Inria)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-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, PSL Research University (PSL)-PSL Research University (PSL)-Université de Cergy Pontoise (UCP), Université Grenoble Alpes (UGA), Harvard University [Cambridge]-Smithsonian Institution, Consejo Superior de Investigaciones Científicas [Spain] (CSIC), 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), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Université Paris-Sud - Paris 11 (UP11)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), École normale supérieure - Paris (ENS Paris), Smithsonian Institution-Harvard University [Cambridge], Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), National Science Foundation (US), Gobierno de Chile, Centre National de la Recherche Scientifique (France), Centre National D'Etudes Spatiales (France), European Research Council, and Institut national des sciences de l'Univers (France)
Subjects: ISM: individual objects: Orion B, statistical [Methods], [SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], FOS: Physical sciences, Astrophysics, ISM: clouds, 01 natural sciences, Momentum, symbols.namesake, 0103 physical sciences, Supersonic speed, 010306 general physics, 010303 astronomy & astrophysics, Methods: statistical, Radio lines: ISM, Equipartition theorem, Astrophysics::Galaxy Astrophysics, QB, ISM: kinematics and dynamics, Physics, Solenoidal vector field, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Turbulence, Star formation, Molecular cloud, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, ISM [Radio lines], individual objects: Orion B [ISM], kinematics and dynamics [ISM], Mach number, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), symbols, clouds [ISM]
Abstract: [Context] The nature of turbulence in molecular clouds is one of the key parameters that control star formation efficiency: compressive motions, as opposed to solenoidal motions, can trigger the collapse of cores, or mark the expansion of Hii regions., [Aims] We try to observationally derive the fractions of momentum density (ρv) contained in the solenoidal and compressive modes of turbulence in the Orion B molecular cloud and relate these fractions to the star formation efficiency in the cloud., [Methods] The implementation of a statistical method applied to a CO(J = 1-0) datacube obtained with the IRAM-30 m telescope, enables us to retrieve 3-dimensional quantities from the projected quantities provided by the observations, which yields an estimate of the compressive versus solenoidal ratio in various regions of the cloud., [Results] Despite the Orion B molecular cloud being highly supersonic (mean Mach number ~ 6), the fractions of motion in each mode diverge significantly from equipartition. The cloud's motions are, on average, mostly solenoidal (excess > 8% with respect to equipartition), which is consistent with its low star formation rate. On the other hand, the motions around the main star forming regions (NGC 2023 and NGC 2024) prove to be strongly compressive., [Conclusions] We have successfully applied to observational data a method that has so far only been tested on simulations, and we have shown that there can be a strong intra-cloud variability of the compressive and solenoidal fractions, these fractions being in turn related to the star formation efficiency. This opens a new possibility for star formation diagnostics in galactic molecular clouds., This work was supported by the CNRS/CNES program Physique et Chimie du Milieu Interstellaire (PCMI). V.V.G. thanks for support from the Chilean Government through the Becas Chile program. P.G.’s postdoctoral position was funded by the INSU/CNRS. P.G. thanks ERC starting grant (3DICE, grant agreement 336474) for funding during this work. NRAO is operated by Associated Universities Inc. under contract with the National Science Foundation.
Published: 2017
Full Text: View/download PDF

48. The ALMA view of UV irradiated cloud edges: unexpected structures and processes

Author: S. Cuadrado, Javier R. Goicoechea, C. Joblin, Octavio Roncero, Alfredo Aguado, Asunción Fuente, John H. Black, E. Chapillon, J. Pety, Emeric Bron, Maryvonne Gerin, José Cernicharo, Belén Tercero, 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 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), Spanish National Research Council [Madrid] (CSIC), Onsala Space Observatory (OSO), Chalmers University of Technology [Göteborg], Instituto de Ciencia de Materiales de Madrid (ICMM), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), AMOR 2018, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Observatorio Astronomico Nacional, Madrid, 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-PSL), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, Astrochemistry, Photon, [SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Molecular cloud, Ab initio, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Photodissociation region, 01 natural sciences, 7. Clean energy, Molecular physics, Astrophysics - Astrophysics of Galaxies, Ion, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, Cluster (physics), Molecule, 010306 general physics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics
Abstract: Far-UV photons (E, Contributed paper to appear in: "Astrochemistry VII, Through the Cosmos from Galaxies to Planets". Proceedings of the IAU Symposium No. 332, 2017, Puerto Varas, Chile. M. Cunningham, T. Millar and Y. Aikawa, eds. (8 pages)
Published: 2017
Full Text: View/download PDF

49. CO spectral line energy distributions in galactic sources: empirical interpretation of extragalactic observations

Author: Antoine Gusdorf, Dariusz C. Lis, Peter Schilke, Maryvonne Gerin, José Cernicharo, Javier R. Goicoechea, Nick Indriolo, Edwin Bergin, European Research Council, Ministerio de Economía y Competitividad (España), National Aeronautics and Space Administration (US), Department of Astronomy [Ann Arbor], University of Michigan [Ann Arbor], University of Michigan System-University of Michigan System, Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Instituto de Ciencia de Materiales de Madrid (ICMM), 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 Institute for Radio Astronomy, and École normale supérieure - Paris (ENS-PSL)
Subjects: FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Spectral line, Interpretation (model theory), 0103 physical sciences, ISM [Galaxies], Astrophysics::Solar and Stellar Astrophysics, Emission spectrum, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, Astrophysics::Galaxy Astrophysics, molecules [ISM], Line (formation), Physics, [PHYS]Physics [physics], 010308 nuclear & particles physics, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Galaxy, ISM: molecules, Interstellar medium, Galaxies: ISM, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Excitation, Energy (signal processing)
Abstract: The relative populations in rotational transitions of CO can be useful for inferring gas conditions and excitation mechanisms at work in the interstellar medium. We present CO emission lines from rotational transitions observed with Herschel/HIFI in the star-forming cores Orion S, Orion KL, Sgr B2(M), and W49N. Integrated line fluxes from these observations are combined with those from Herschel/PACS observations of the same sources to construct CO spectral line energy distributions (SLEDs) from 5 ≤ J ≤ 48. These CO SLEDs are compared to those reported in other galaxies, with the intention of empirically determining which mechanisms dominate excitation in such systems. We find that CO SLEDs in Galactic star-forming cores cannot be used to reproduce those observed in other galaxies, although the discrepancies arise primarily as a result of beam filling factors. The much larger regions sampled by the Herschel beams at distances of several megaparsecs contain significant amounts of cooler gas, which dominate the extragalactic CO SLEDs, in contrast to observations of Galactic star-forming regions, which are focused specifically on cores containing primarily hot molecular gas., Support for this work was provided by NASA through an award issued by JPL/Caltech. J.R.G. and J.C. thank the ERC for support under grant ERC-2013-Syg-610256-NANOCOSMOS, and the Spanish MINECO for support under grant AYA2012-32032.
Published: 2017
Full Text: View/download PDF

50. The Far Infrared Spectroscopic Explorer (FIRSPEX): probing the lifecycle of the ISM in the universe

Author: Dimitra Rigopoulou, J. D. Gallego, Martina C. Wiedner, Giorgio Savini, Xander Tielens, S. Viti, Volker Ossenkopf-Okada, Dariusz C. Lis, Martin E. Caldwell, Emmanuel Caux, C. Kramer, Sergio Molinari, Maryvonne Gerin, Paul F. Goldsmith, Chris Pearson, Boon-Kok Tan, Asantha Cooray, Brian N. Ellison, Javier R. Goicoechea, Ghassan Yassin, MacEwan, Howard A., Fazio, Giovanni G., Lystrup, Makenzie, Batalha, Natalie, Siegler, Nicholas, and Tong, Edward C.
Subjects: Heterodyne, Physics, Star formation, Terahertz radiation, media_common.quotation_subject, Molecular cloud, Bolometer, Astrophysics::Instrumentation and Methods for Astrophysics, Astronomy, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Galaxy, law.invention, Far infrared, Sky, law, 0103 physical sciences, 010306 general physics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, media_common
Abstract: The Far Infrared Spectroscopic Explorer (FIRSPEX) is a novel European-led astronomy mission concept developed to enable large area ultra high spectroscopic resolution surveys in the THz regime. FIRSPEX opens up a relatively unexplored spectral and spatial parameter space that will produce an enormously significant scientific legacy by focusing on the properties of the multi-phase ISM, the assembly of molecular clouds in our Galaxy and the onset of star formation; topics which are fundamental to our understanding of galaxy evolution. The mission uses a heterodyne instrument and a ~1.2 m primary antenna to scan large areas of the sky in a number of discreet spectroscopic channels from L2. The FIRSPEX bands centered at [CI] 809 GHz, [NII]1460 GHz, [CII]1900 GHz and [OI]4700 GHz have been carefully selected to target key atomic and ionic fine structure transitions difficult or impossible to access from the ground but fundamental to the study of the multi-phase ISM in the Universe. The need for state-of-the-art sensitivity dictates the use of superconducting mixers configured either as tunnel junctions or hot electron bolometers. This technology requires cooling to low temperatures, approaching 4K, in order to operate. The receivers will operate in double sideband configuration providing a total of 7 pixels on the sky. FIRSPEX will operate from L2 in both survey and pointed mode enabling velocity resolved spectroscopy of large areas of sky as well as targeted observations.
Published: 2016
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

Publication Type

Journal

Database

Publisher

154 results on '"Javier R. Goicoechea"'

Search Results

Catalog

Select search scope, currently: Articles

Catalog

books, media & more in Jio Institute collections

Articles

journal articles & other e-resources