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arXiv · 1007.2550

Nitrogen hydrides in interstellar gas: Herschel/HIFI observations towards G10.6-0.4 (W31C)

C. M. Persson·J. H. Black·J. Cernicharo·J. R. Goicoechea·G. E. Hassel·E. Herbst·M. Gerin·M. De Luca·T. A. Bell·A. Coutens·E. Falgarone·P. F. Goldsmith·H. Gupta·M. Kazmierczak·D. C. Lis·B. Mookerjea·D. A. Neufeld·J. Pearson·T. G. Phillips·P. Sonnentrucker·J. Stutzki·C. Vastel·S. Yu·F. Boulanger·E. Dartois·P. Encrenaz·T. R. Geballe·T. Giesen·B. Godard·C. Gry·P. Hennebelle·P. Hily-Blant·C. Joblin·R. Kolos·J. Krelowski·J. Martin-Pintado·K. Menten·R. Monje·M. Perault·R. Plume·M. Salez·S. Schlemmer·M. Schmidt·D. Teyssier·I. Peron·P. Cais·P. Gaufre·A. Cros·L. Ravera·P. Morris·S. Lord·P. Planesas
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Abstract

The HIFI instrument on board the Herschel Space Observatory has been used to observe interstellar nitrogen hydrides along the sight-line towards G10.6-0.4 in order to improve our understanding of the interstellar chemistry of nitrogen. We report observations of absorption in NH N=1-0, J=2-1 and ortho-NH2 1_1,1-0_0,0. We also observed ortho-NH3 1_0-0_0, and 2_0-1_0, para-NH3 2_1-1_1, and searched unsuccessfully for NH+. All detections show emission and absorption associated directly with the hot-core source itself as well as absorption by foreground material over a wide range of velocities. All spectra show similar, non-saturated, absorption features, which we attribute to diffuse molecular gas. Total column densities over the velocity range 11-54 km/s are estimated. The similar profiles suggest fairly uniform abundances relative to hydrogen, approximately 6*10^-9, 3*10^-9, and 3*10^-9 for NH, NH2, and NH3, respectively. These abundances are discussed with reference to models of gas-phase and surface chemistry.

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C. M. Persson, J. H. Black, J. Cernicharo, J. R. Goicoechea, G. E. Hassel, E. Herbst, M. Gerin, M. De Luca, T. A. Bell, A. Coutens, E. Falgarone, P. F. Goldsmith, H. Gupta, M. Kazmierczak, D. C. Lis, B. Mookerjea, D. A. Neufeld, J. Pearson, T. G. Phillips, P. Sonnentrucker, J. Stutzki, C. Vastel, S. Yu, F. Boulanger, E. Dartois, P. Encrenaz, T. R. Geballe, T. Giesen, B. Godard, C. Gry, P. Hennebelle, P. Hily-Blant, C. Joblin, R. Kolos, J. Krelowski, J. Martin-Pintado, K. Menten, R. Monje, M. Perault, R. Plume, M. Salez, S. Schlemmer, M. Schmidt, D. Teyssier, I. Peron, P. Cais, P. Gaufre, A. Cros, L. Ravera, P. Morris, S. Lord, P. Planesas. 2010-07-15. Nitrogen hydrides in interstellar gas: Herschel/HIFI observations towards G10.6-0.4 (W31C). https://doi.org/10.1051/0004-6361/201015105

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