Far-Infrared detection of H2D+ toward Sgr B2
arXiv:astro-ph/0701559 · doi:10.1086/512857
Abstract
We report on the first far-IR detection of H2D+, using the Infrared Space Observatory, in the line of sight toward Sgr B2 in the galactic center. The transition at 126.853 um connecting the ground level of o-H2D+, 1_1,1 with the the 2_1,2 level at 113 K, is observed in absorption against the continuum emission of the cold dust of the source. The line is broad, with a total absorption covering 350 km s^-1, i.e., similar to that observed in the fundamental transitions of H2O, OH and CH at ~179, 119 and 149 um respectively. For the physical conditions of the different absorbing clouds the H2D+ column density ranges from 2 to 5x10^13 cm^-2, i.e., near an order of magnitude below the upper limits obtained from ground based submillimeter telescopes. The derived H2D+ abundance is of a few 10^-10, which agrees with chemical models predictions for a gas at a kinetic temperature of ~20K.
Accepted in ApJ letters. Non edited
References in corpus (7)
- First detection of triply-deuterated methanol
- The importance of the ortho:para H2 ratio for the deuteration of molecules during pre-protostellar collapse
- The Distribution of Ortho-H_2D+(1_1,0 - 1_1,1) in L1544: Tracing the Deuteration Factory in Prestellar Cores
- Detection of H2D+ in a massive prestellar core in Orion B
- Deuterium enhancement in H3+ in prestellar cores
- Probable detection of H2D+ in the starless core Barnard 68
- H_2D^+: a light on baryonic dark matter?