4464 articles – 13151 references  [version française]
 HAL: hal-00485859, version 1
 arXiv: 1005.5653
 Interstellar OH+ , H2O+ and H3O+ along the sight-line to G10.6-0.4
 Maryvonne Gerin 1, M. De Luca 1
 For the PRISMAS collaboration(s)
 (2010-05-21)
 We report the detection of absorption lines by the reactive ions OH+, H2O+ and H3O+ along the line of sight to the submillimeter continuum source G10.6$-$0.4 (W31C). We used the Herschel HIFI instrument in dual beam switch mode to observe the ground state rotational transitions of OH+ at 971~GHz, H2O+ at 1115 and 607~GHz, and H3O+ at 984 GHz. The resultant spectra show deep absorption over a broad velocity range that originates in the interstellar matter along the line of sight to G10.6$-$0.4 as well as in the molecular gas directly associated with that source. The OH+ spectrum reaches saturation over most velocities corresponding to the foreground gas, while the opacity of the H2O+ lines remains lower than 1 in the same velocity range, and the H3O+ line shows only weak absorption. For LSR velocities between 7 and 50 kms$^{-1}$ we estimate total column densities of $N$(OH+) $> 2.5 \times 10^{14}$ cm$^{-2}$, $N$(H2O+) $\sim 6 \times 10^{13}$ cm$^{-2}$ and $N$(H3O+) $\sim 4.0 \times 10^{13}$ cm$^{-2}$. These detections confirm the role of O$^+$ and OH$^+$ in initiating the oxygen chemistry in diffuse molecular gas and strengthen our understanding of the gas phase production of water. The high ratio of the OH+ by the H2O+ column density implies that these species predominantly trace low-density gas with a small fraction of hydrogen in molecular form.
 1: Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA) CNRS : UMR8112 – INSU – Observatoire de Paris – Université Pierre et Marie Curie [UPMC] - Paris VI – Université de Cergy Pontoise – Ecole normale supérieure de Paris - ENS Paris 2: Onsala space observatory (oso) Chalmers University of Technology 3: Department of Physics (OHIO STATE UNIVERSITY) Ohio State University 4: Departments of Astronomy and Chemistry The Ohio State University 5: centro de astrobiologia (CAB-INTA) Instituto Nacional de Técnica Aeroespacial 6: Centro de Investigaciones Biológicas (CSIC) Consejo Superior de Investigaciones Cientificas 7: Jet Propulsion Laboratory [NASA] (JPL) NASA – California Institute of Technology 8: CalTech-CSO (CSO) California Institute of Technology 9: Department of physics and astronomy The John Hopkins University 10: Institut d'astrophysique spatiale (IAS) CNRS : UMR8617 – INSU – Université Paris XI - Paris Sud 11: Centre d'étude spatiale des rayonnements (CESR) CNRS : UMR5187 – Observatoire Midi-Pyrénées – INSU – Université Paul Sabatier [UPS] - Toulouse III 12: I physikalisches institut University of Cologne 13: Laboratoire d'Astrophysique de Marseille (LAM) CNRS : UMR6110 – INSU – Université de Provence - Aix-Marseille I 14: Laboratoire d'Astrophysique de Grenoble (LAOG) CNRS : UMR5571 – OSUG – INSU – Université Joseph Fourier - Grenoble I 15: Center for astronomy Nicolaus Copernicus University 16: Institute of physical chemistry Polish Academy of Sciences 17: Instituto de Estructura de la Materia (IEM) Consejo Superior de Investigaciones Cientificas 18: Tata Institute for fundamental research tata institute for fundamental research 19: Department of physics and astronomy Univetsity of calgary – University of Calgary 20: Nicolaus Copernicus Astronomical Center Polish Academy of Sciences 21: MPI fur Extraterrestrische Physik (MPE) Max-Planck-Institut 22: MPI f"ur Radioastronomie (MpIfR) Max-Planck-Institut 23: Gemini Telescope Gemini Telescope 24: Institute for Space Research Netherlands (SRON) SRON Netherlands Institute for Space Research 25: Sterrewacht Leiden Leiden University 26: Deutsches Zentrum fur Luft- und Raumfahrt Deutsches Zentrum fur Luft and Raumfahrt 27: Laboratoire Lasers, Plasmas et Procédés photoniques (LP3) CNRS : UMR6182 – Université de la Méditerranée - Aix-Marseille II 28: Osservatorio Astrofisico di Arcetri INAF
 Subject : Sciences of the Universe/Astrophysics/Galactic AstrophysicsPhysics/Astrophysics/Galactic Astrophysics
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 hal-00485859, version 1 http://hal.archives-ouvertes.fr/hal-00485859 oai:hal.archives-ouvertes.fr:hal-00485859 From: Maryvonne Gerin <> Submitted on: Wednesday, 26 May 2010 11:35:49 Updated on: Monday, 31 May 2010 12:26:37