SIMBAD references

2012A&A...542L...7W - Astronomy and Astrophysics, volume 542, L7-7 (2012/6-1)

High-resolution absorption spectroscopy of the OH 2Π3/2 ground state line.

WIESEMEYER H., GUESTEN R., HEYMINCK S., JACOBS K., MENTEN K.M., NEUFELD D.A., REQUENA-TORRES M.A. and STUTZKI J.

Abstract (from CDS):

The chemical composition of the interstellar medium is determined by gas phase chemistry, assisted by grain surface reactions, and by shock chemistry. The aim of this study is to measure the abundance of the hydroxyl radical (OH) in diffuse spiral arm clouds as a contribution to our understanding of the underlying network of chemical reactions. Owing to their high critical density, the ground states of light hydrides provide a tool to directly estimate column densities by means of absorption spectroscopy against bright background sources. We observed onboard the SOFIA observatory the 2Π3/2, J=5/2←3/2 2.5THz line of ground-state OH in the diffuse clouds of the Carina-Sagittarius spiral arm. OH column densities in the spiral arm clouds along the sightlines to W49N, W51 and G34.26+0.15 were found to be of the order of 1014cm–2, which corresponds to a fractional abundance of 10–7 to 10–8, which is comparable to that of H2O. The absorption spectra of both species have similar velocity components, and the ratio of the derived H2O to OH column densities ranges from 0.3 to 1.0. In W49N we also detected the corresponding line of 18OH.

Abstract Copyright:

Journal keyword(s): ISM: molecules - ISM: clouds - ISM: lines and bands

CDS comments: Paragraph 1. G35.10-0.74 is a probable misprint for G35.20-0.74

Simbad objects: 10

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2019.09.22-13:05:45

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