Falgarone, E. and Lord, S. and Phillips, T. G. (2010) Strong CH^+ J = 1–0 emission and absorption in DR21. Astronomy and Astrophysics, 518 . L118. ISSN 0004-6361 http://resolver.caltech.edu/CaltechAUTHORS:20101116-100342718
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We report the first detection of the ground-state rotational transition of the methylidyne cation CH^+ towards the massive star-forming region DR 21 with the HIFI instrument onboard the Herschel satellite. The line profile exhibits a broad emission line, in addition to two deep and broad absorption features associated with the DR 21 molecular ridge and foreground gas. These observations allow us to determine a ^(12)CH^(+)J = 1–0 line frequency of ν = 835 137 ± 3 MHz, in good agreement with a recent experimental determination. We estimate the CH^+ column density to be a few 10^(13) cm^(-2) in the gas seen in emission, and >10^(14) cm^(-2) in the components responsible for the absorption, which is indicative of a high line of sight average abundance [CH^+] /[H] > 1.2 × 10^(-8). We show that the CH^+ column densities agree well with the predictions of state-of-the-art C-shock models in dense UV-illuminated gas for the emission line, and with those of turbulent dissipation models in diffuse gas for the absorption lines.
|Additional Information:||© 2010 ESO. Received 31 March 2010; Accepted 15 May 2010; Published online 16 July 2010. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA. HIFI has been designed and built by a consortium of institutes and university departments from across Europe, Canada and the United States (NASA) under the leadership of SRON, Netherlands Institute for Space Research, Groningen, The Netherlands, and with major contributions from Germany, France and the US. Consortium members are: Canada: CSA, U. Waterloo; France: CESR, LAB, LERMA, IRAM; Germany: KOSMA, MPIfR, MPS; Ireland: NUI Maynooth; Italy: ASI, IFSI-INAF, Osservatorio Astrofisico di Arcetri-INAF; Netherlands: SRON, TUD; Poland: CAMK, CBK; Spain: Observatorio Astronòmico Nacional (IGN), Centro de Astrobiologia; Sweden: Chalmers University of Technology – MC2, RSS & GARD, Onsala Space Observatory, Swedish National Space Board, Stockholm University – Stockholm Observatory; Switzerland: ETH Zurich, FHNW; USA: CalTech, JPL, NHSC. M.G. and E.F. acknowledge the support from the Centre National de Recherche Spatiale (CNES). Part of this work was supported by the German Deutsche Forschungsgemeinschaft, DFG project # Os177/1–1. We thank G. Pineau des Forêts for providing us with his version of the code for C-shock models.|
|Subject Keywords:||astrochemistry; ISM: molecules; ISM: kinematics and dynamics; turbulence|
|Official Citation:||Strong CH+ J = 1–0 emission and absorption in DR21 E. Falgarone, V. Ossenkopf, M. Gerin, P. Lesaffre, B. Godard, J. Pearson, S. Cabrit, Ch. Joblin, A. O. Benz, F. Boulanger, A. Fuente, R. Güsten, A. Harris, T. Klein, C. Kramer, S. Lord, P. Martin, J. Martin-Pintado, D. Neufeld, T. G. Phillips, M. Röllig, R. Simon, J. Stutzki, F. van der Tak, D. Teyssier, H. Yorke, N. Erickson, M. Fich, W. Jellema, A. Marston, C. Risacher, M. Salez and F. Schmülling A&A 518 L118 (2010) DOI: 10.1051/0004-6361/201014671|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Jason Perez|
|Deposited On:||16 Nov 2010 19:16|
|Last Modified:||26 Dec 2012 12:38|
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