Strong CH+ J=1-0 emission and absorption in DR21
| Title | Strong CH+ J=1-0 emission and absorption in DR21 |
| Publication Type | Journal Article |
| Year of Publication | 2010 |
| Authors | Falgarone, E, Ossenkopf, V, Gerin, M, Lesaffre, P, Godard, B, Pearson, J, Cabrit, S, Joblin, C, Benz, AO, Boulanger, F, Fuente, A, Gusten, R, Harris, A, Klein, T, Kramer, C, Lord, S, Martin, P, Martin-Pintado, J, Neufeld, D, Phillips, TG, Rollig, M, Simon, R, Stutzki, J, van der Tak, F, Teyssier, D, Yorke, H, Erickson, N, Fich, M, Jellema, W, Marston, A, Risacher, C, Salez, M, Schmulling, F |
| Journal | Astronomy & Astrophysics |
| Volume | 518 |
| Date Published | Jul-Aug |
| ISBN Number | 0004-6361 |
| Accession Number | WOS:000281527200119 |
| Abstract | 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 (CH+)-C-12 J = 1-0 line frequency of v = 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 x 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. |
