Molecular oxygen in the rho Ophiuchi cloud
Abstract
Molecular oxygen, O2 has been expected historically to be an abundant component of the chemical species in molecular clouds and, as such, an important coolant of the dense interstellar medium. However, a number of attempts from both ground and from space have failed to detect O2 emission. The work described here uses heterodyne spectroscopy from space to search for molecular oxygen in the interstellar medium. The Odin satellite carries a 1.1 m sub-millimeter dish and a dedicated 119 GHz receiver for the ground state line of O2. Starting in 2002, the star forming molecular cloud core rho Oph A was observed with Odin for 34 days during several observing runs. We detect a spectral line at v(LSR) = 3.5 km/s with dv(FWHM) = 1.5 km/s, parameters which are also common to other species associated with rho Ohp A. This feature is identified as the O2 (N_J = 1_1 - 1_0) transition at 118 750.343 MHz. The abundance of molecular oxygen, relative to H2,, is 5E-8 averaged over the Odin beam. This abundance is consistently lower than previously reported upper limits.
Cite
@article{arxiv.astro-ph/0702474,
title = {Molecular oxygen in the rho Ophiuchi cloud},
author = {B. Larsson and R. Liseau and L. Pagani and P. Bergman and P. Bernath and N. Biver and J. H. Black and R. S. Booth and V. Buat and J. Crovisier and C. L. Curry and M. Dahlgren and P. J. Encrenaz and E. Falgarone and P. A. Feldman and M. Fich and H. G. Flore'n and M. Fredrixon and U. Frisk and G. F. Gahm and M. Gerin and M. Hagstroem and J. Harju and T. Hasegawa and Aa. Hjalmarson and C. Horellou and L. E. B. Johansson and K. Justtanont and A. Klotz and E. Kyroelae and S. Kwok and A. Lecacheux and T. Liljestroem and E. J. Llewellyn and S. Lundin and G. Me'gie and G. F. Mitchell and D. Murtagh and L. H. Nordh and L. -Aa. Nyman and M. Olberg and A. O. H. Olofsson and G. Olofsson and H. Olofsson and G. Persson and R. Plume and H. Rickman and I. Ristorcelli and G. Rydbeck and Aa. Sandqvist and F. v. Sche'ele and G. Serra and S. Torchinsky and N. F. Tothill and K. Volk and T. Wiklind and C. D. Wilson and A. Winnberg and G. Witt},
journal= {arXiv preprint arXiv:astro-ph/0702474},
year = {2009}
}
Comments
10 pages, 11 figures, accepted for publication in A&A