Interstellar OH+, H2O+ and H3O+ along the sight-line to G10.6–0.4

By M. Gerin, M. Luca, J. Black, E. Herbst, Javier R.Goicoechea, E. Falgarone, B. Godard, J. Pearson, D. Lis, T. Phillips and 43 more. 2010

147 citations recorded by the source corpus.

We report the detection of absorption lines by the reactive ions OH + ,H 2O + 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 × 10 14 cm −2 , N(H2O + ) ∼6 × 10 13 cm −2 and N(H3O + ) ∼4.0 × 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

Subfields: Astronomy and Astrophysics, Atmospheric Science

View Paper: https://www.semanticscholar.org/paper/37c467c9ecc94edee01ee6aaaa10eaf78ed98110

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In Astronomy and Astrophysics

1. B. McGuire
2. Simon Bruderer
3. K. Menten
4. F. Wyrowski
5. Peter Schilke
6. S. Madden
7. I. Grenier
8. A. Cooray

In Atmospheric Science

1. Simon Bruderer
2. B. McGuire
3. Peter Schilke
4. K. Menten
5. M. Wolfire
6. J. Black
7. A. Strong
8. M. Sauvage

Citations in the corpus

• 2018 Census of Interstellar, Circumstellar, Extragalactic, Protoplanetary Disk, and Exoplanetary Molecules (2018, methodology): “Nearly simultaneously, Benz et al. (2010) reported the detection of the 1→ 0, 3/2→ 1/2 transitions at 1033 GHz toward W3 IRS5 using Herschel/HIFI, and Gerin et al. (2010) reported a detection along the line of sight to W31C, also with Herschel/HIFI.”
• The Nine Lives of Cosmic Rays in Galaxies (2015, methodology): “Interstellar OH+ was first detected by Wyrowski et al. (2010) with the Atacama Pathfinder EXperiment (APEX) telescope shortly before the first surveys of this ion with the HIFI instrument aboard Herschel Space Observatory were completed (Gerin et al. 2010, Neufeld et al. 2010).”
• INVESTIGATING THE COSMIC-RAY IONIZATION RATE IN THE GALACTIC DIFFUSE INTERSTELLAR MEDIUM THROUGH OBSERVATIONS OF H+3 (2011, background): “…et al. 1978; Hartquist et al. 1978a,b; van Dishoeck & Black 1986; Federman et al. 1996; van der Tak & van Dishoeck 2000; McCall et al. 2003; Indriolo et al. 2007; Gerin et al. 2010; Neufeld et al. 2010) produced a wide range of ionization rates, from a few times 10−18 s−1 to a few times 10−15 s−1.”
• OBSERVATIONS OF Arp 220 USING HERSCHEL-SPIRE: AN UNPRECEDENTED VIEW OF THE MOLECULAR GAS IN AN EXTREME STAR FORMATION ENVIRONMENT (2011, background): “The detections of OH+ and H2O + are very important in Arp 220 for modeling the water transitions because they are the major intermediaries in the ion-neutral chemistry network producing water in the ISM (Gerin et al. 2010; Neufeld et al. 2010a), and their detection is very difficult from current gro”
• HERSCHEL SURVEY OF GALACTIC OH+, H2O+, AND H3O+: PROBING THE MOLECULAR HYDROGEN FRACTION AND COSMIC-RAY IONIZATION RATE (2014, background): “All species studied here (OH+, o-H2O +, p-H2O +, and H3O +) were previously reported in absorption by Gerin et al. (2010b).”