CH+(1-0) and 13CH+(1-0) absorption lines in the direction of massive star-forming regions

E. Falgarone; B. Godard; J. Cernicharo; M. De Luca; M. Gerin; T. G. Phillips; J. H. Black; D. C. Lis; T. A. Bell; F. Boulanger; A. Coutens; E. Dartois; P. Encrenaz; T. Giesen; J. R. Goicoechea; P. F. Goldsmith; H. C. Gupta; C. Gry; P. Hennebelle; E. Herbst; P. Hily-Blant; C. Joblin; M. Kaźmierczak; R. Kołos; J. Krełowski; J. Martin-Pintado; R. Monje; B. Mookerjea; D. A. Neufeld; M. Perault; J. C. Pearson; C. Persson; R. Plume; M. Salez; M. Schmidt; P. Sonnentrucker; J. Stutzki; D. Teyssier; C. Vastel; S. Yu; K. Menten; T. R. Geballe; S. Schlemmer; R. Shipman; A. G. G. M. Tielens; S. Philipp; A. Cros; J. Zmuidzinas; L. A. Samoska; K. Klein; A. Lorenzani; R. Szczerba; I. Péron; P. Gaufre; L. Ravera; P. Morris; S. Lord; P. Planesas; Ph. Cais

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ADS Bibliographic id: 2010A&A...521L..15F

DOI: 10.1051/0004-6361/201015109

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Astronomy and Astrophysics 521 (2010) L15

CH+(1-0) and 13CH+(1-0) absorption lines in the direction of massive star-forming regions

E. Falgarone ¹, B. Godard, J. Cernicharo ², M. De Luca ³, M. Gerin ^1, 3, T. G. Phillips ⁴, J. H. Black, D. C. Lis ⁴, T. A. Bell, F. Boulanger ⁵, A. Coutens ⁶, E. Dartois ⁵, P. Encrenaz ³, T. Giesen, J. R. Goicoechea ³, P. F. Goldsmith, H. C. Gupta ⁷, C. Gry ⁸, P. Hennebelle ⁶, E. Herbst ⁹, P. Hily-Blant ⁶, C. Joblin ¹⁰, M. Kaźmierczak, R. Kołos, J. Krełowski, J. Martin-Pintado ⁶, R. Monje, B. Mookerjea ¹¹, D. A. Neufeld, M. Perault ¹, J. C. Pearson, C. Persson ¹², R. Plume, M. Salez ⁶, M. Schmidt ¹³, P. Sonnentrucker, J. Stutzki ⁶, D. Teyssier ¹⁴, C. Vastel ^10, 15, S. Yu, K. Menten, T. R. Geballe, S. Schlemmer, R. Shipman, A. G. G. M. Tielens ¹⁶, S. Philipp, A. Cros, J. Zmuidzinas, L. A. Samoska, K. Klein ¹⁷, A. Lorenzani ¹⁸, R. Szczerba, I. Péron, P. Gaufre, L. Ravera ¹⁰, P. Morris, S. Lord ⁶, P. Planesas, Ph. Cais ^{19, 20, 21, 22}

(2010-10)

We report the detection of the ground-state rotational transition of the methylidyne cation CH+ and its isotopologue 13CH+ toward the remote massive star-forming regions W33A, W49N, and W51 with the HIFI instrument onboard the Herschel satellite. Both lines are seen only in absorption against the dust continuum emission of the star-forming regions. The CH+ absorption is saturated over almost the entire velocity ranges sampled by the lines-of-sight that include gas associated with the star-forming regions (SFR) and Galactic foreground material. The CH+ column densities are inferred from the optically thin components. A lower limit of the isotopic ratio [ 12CH+] /[ 13CH+] > 35.5 is derived from the absorptions of foreground material toward W49N. The column density ratio, N(CH+)/N(HCO+), is found to vary by at least a factor 10, between 4 and >40, in the Galactic foreground material. Line-of-sight 12CH+ average abundances relative to total hydrogen are estimated. Their average value, N(CH+)/NH > 2.6×10-8, is higher than that observed in the solar neighborhood and confirms the high abundances of CH+ in the Galactic interstellar medium. We compare this result to the predictions of turbulent dissipation regions (TDR) models and find that these high abundances can be reproduced for the inner Galaxy conditions. It is remarkable that the range of predicted N(CH+)/N(HCO+) ratios, from 1 to ~50, is comparable to that observed. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.Appendix (page 6) is only available in electronic form at http://www.aanda.org

1:	Laboratoire de Radio Astronomie de l'ENS (LRA)

	CNRS : FRE2460 – Observatoire de Paris

2:	Centro de Investigaciones Biológicas (CSIC)

	Consejo Superior de Investigaciones Cientificas

3:	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

4:	California Institute of Technology

	California Institute of Technology

5:	Institut d'astrophysique spatiale (IAS)

	CNRS : UMR8617 – INSU – Université Paris XI - Paris Sud

6:	Laboratoire d'Astrophysique de Grenoble (LAOG)

	CNRS : UMR5571 – OSUG – INSU – Université Joseph Fourier - Grenoble I

7:	Physics Department

	Aucune

8:	Laboratoire d'Astrophysique de Marseille (LAM)

	CNRS : UMR6110 – INSU – Université de Provence - Aix-Marseille I

9:	The Ohio State University (Department of Physics)

	The Ohio State University

10:	Centre d'étude spatiale des rayonnements (CESR)

	CNRS : UMR5187 – Observatoire Midi-Pyrénées – INSU – Université Paul Sabatier [UPS] - Toulouse III

11:	KOSMA, I. Physikalisches Institut

	Universität zu Köln

12:	Department of Materials Science and Engineering, KTH (KTH)

	Department of Materials Science and Engineering, KTH

13:	Department of Obstetrics and Gynecology

	J. Gutenberg-University

14:	Herschel Science Center

	ESA

15:	Centre d'Etude Spatiale des Rayonnements

	Aucune

16:	Institute for Space Research Netherlands (SRON)

	SRON Netherlands Institute for Space Research

17:	Deutsches Zentrum fur Luft- und Raumfahrt

	Deutsches Zentrum fur Luft and Raumfahrt

18:	Osservatorio Astrofisico di Arcetri

	INAF

19:	Université Sciences et Technologies - Bordeaux 1

	Université Sciences et Technologies - Bordeaux I

20:	Observatoire aquitain des sciences de l'univers (OASU)

	CNRS : UMS2567 – INSU – Université Sciences et Technologies - Bordeaux I

21:	Laboratoire d'Astrophysique de Bordeaux (LAB)

	CNRS : UMR5804 – INSU – Université Sciences et Technologies - Bordeaux I

22:	Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux (L3AB)

	CNRS : UMR5804 – INSU – Université Sciences et Technologies - Bordeaux I

Subject

Sciences of the Universe/Astrophysics/Solar and Stellar Astrophysics

Physics/Astrophysics/Solar and Stellar Astrophysics

Keyword(s): astrochemistry – ISM: molecules – ISM: kinematics and dynamics – turbulence


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Submitted on: Thursday, 2 December 2010 12:02:30
Updated on: Thursday, 2 December 2010 12:02:30