Odin has successfully observed three regions in the Orion A cloud, i.e. Ori KL, Ori S and the Orion Bar, in the 572.5 GHz rotational ground state line of ammonia, ortho-NH3 (J,K) = (1,0) -> (0,0), and the result for the Orion Bar represents the first detection in an ammonia line. Several velocity components are present in the data. Specifically, the observed line profile from the Orion Bar can be decomposed into two components, which are in agreement with observations in high-J CO lines by Wilson et al. 2001. Using the source model for the Orion Bar by these authors, our Odin observation implies a total ammonia abundance of NH3/H2 = 5E-9.
@article{arxiv.astro-ph/0303122,
title = {First NH3 detection of the Orion Bar},
author = {B. Larsson and R. Liseau and P. Bergman and P. Bernath and J. H. Black and R. S. Booth and V. Buat and C. L. Curry and P. Encrenaz and E. Falgarone and P. Feldman and M. Fich and H. G. Flore'n and U. Frisk and M. Gerin and E. M. Gregersen and J. Harju and T. Hasegawa and L. E. B. Johansson and S. Kwok and A. Lecacheux and T. Liljestrom and K. Mattila and G. F. Mitchell and L. H. Nordh and M. Olberg and G. Olofsson and L. Pagani and R. Plume and I. Ristorcelli and Aa. Sandqvist and F. v. Sche'ele and N. F. H. Tothill and K. Volk and C. D. Wilson and A. Hjalmarson},
journal= {arXiv preprint arXiv:astro-ph/0303122},
year = {2009}
}
Comments
4 pages with 2 figures, accepted for publication in A&A