Detection of interstellar oxidaniumyl: Abundant H2O+ towards the star-forming regions DR21, Sgr B2, and NGC6334

V. Ossenkopf 1, 2 H. S. P. Müller D. C. Lis 3 P. Schilke 4, 5 T. A. Bell S. Bruderer 6 E. Bergin 7 C. Ceccarelli 8 C. Comito 5 J. Stutzki 4 A. Bacmann 9 Alain Baudry 9 A. O. Benz 10 M. Benedettini 8 O. Berne 11 G. Blake 12 A. Boogert 8 S. Bottinelli 13 F. Boulanger 14 S. Cabrit 15 P. Caselli 16 E. Caux 17, 18 J. Cernicharo 19 C. Codella 8 A. Coutens 8 N. Crimier 8 N. R. Crockett F. Daniel 15, 19, 20 K. Demyk 8 P. Dieleman 2 C. Dominik 21 M. L. Dubernet 15 M. Emprechtinger 22 P. Encrenaz 15 E. Falgarone 23 K. France A. Fuente 8 M. Gerin 15, 23 T. F. Giesen A. M. Di Giorgio 24 J. R. Goicoechea 15 P. F. Goldsmith R. Güsten 5 A. Harris 25 F. Helmich 8 E. Herbst 26, 27 P. Hily-Blant 8 K. Jacobs 28 T. Jacq 9 Ch. Joblin D. Johnstone 29 C. Kahane 8 M. Kama 8 T. Klein 30 A. Klotz 13, 31 C. Kramer 32 W. Langer 8 B. Lefloch 8 C. Leinz A. Lorenzani 16 S. D. Lord S. Maret 8 P. G. Martin 33 J. Martin-Pintado 8 C. Mccoey 24 M. Melchior G. J. Melnick 34 K. M. Menten 30 B. Mookerjea 35 P. Morris 36 J. A. Murphy D. A. Neufeld B. Nisini 37 S. Pacheco 8 L. Pagani 15 B. Parise 13, 38 J. C. Pearson 24 M. Pérault 15 T. G. Phillips 3 R. Plume 39 S.-L. Quin R. Rizzo M. Röllig M. Salez 8 P. Saraceno 40 S. Schlemmer 4 R. Simon 41 K. Schuster 8 F. F. S. Van Der Tak 2, 42 A. G. G. M. Tielens 2 D. Teyssier N. Trappe 43 C. Vastel 17, 18 S. Viti 8 Valentine Wakelam 44 A. Walters 8 S. Wang 7 N. Whyborn M. Van Der Wiel 8 H. W. Yorke S. Yu 45 J. Zmuidzinas 22
9 FORMATION STELLAIRE 2010
L3AB - Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux, OASU - Observatoire aquitain des sciences de l'univers, LAB - Laboratoire d'Astrophysique de Bordeaux [Pessac], Université Sciences et Technologies - Bordeaux 1
44 AMOR 2010
L3AB - Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux, OASU - Observatoire aquitain des sciences de l'univers, LAB - Laboratoire d'Astrophysique de Bordeaux [Pessac], Université Sciences et Technologies - Bordeaux 1
Abstract : Aims: We identify a prominent absorption feature at 1115 GHz, detected in first HIFI spectra towards high-mass star-forming regions, and interpret its astrophysical origin. Methods: The characteristic hyperfine pattern of the H2O+ ground-state rotational transition, and the lack of other known low-energy transitions in this frequency range, identifies the feature as H2O+ absorption against the dust continuum background and allows us to derive the velocity profile of the absorbing gas. By comparing this velocity profile with velocity profiles of other tracers in the DR21 star-forming region, we constrain the frequency of the transition and the conditions for its formation. Results: In DR21, the velocity distribution of H2O+ matches that of the [C ii] line at 158 μm and of OH cm-wave absorption, both stemming from the hot and dense clump surfaces facing the H ii-region and dynamically affected by the blister outflow. Diffuse foreground gas dominates the absorption towards Sgr B2. The integrated intensity of the absorption line allows us to derive lower limits to the H2O+ column density of 7.2 × 1012 cm-2 in NGC 6334, 2.3 × 1013 cm-2 in DR21, and 1.1 × 1015 cm-2 in Sgr B2. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.
Type de document :
Article dans une revue
Astronomy and Astrophysics - A&A, EDP Sciences, 2010, 518, pp.L111. 〈10.1051/0004-6361/201014577〉
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Soumis le : mardi 18 octobre 2011 - 15:23:19
Dernière modification le : jeudi 7 décembre 2017 - 12:34:12

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V. Ossenkopf, H. S. P. Müller, D. C. Lis, P. Schilke, T. A. Bell, et al.. Detection of interstellar oxidaniumyl: Abundant H2O+ towards the star-forming regions DR21, Sgr B2, and NGC6334. Astronomy and Astrophysics - A&A, EDP Sciences, 2010, 518, pp.L111. 〈10.1051/0004-6361/201014577〉. 〈hal-00633453〉

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