Variations between Dust and Gas in the Diffuse Interstellar Medium. 2. Search for Cold Gas [GA]

http://arxiv.org/abs/1611.04475


The content of interstellar clouds, in particular the inventory of diffuse molecular gas, remains uncertain. We identified a sample of isolated clouds, approximately 100 solar masses in size, and used the dust content to estimate the total amount of gas. In Paper 1, the total inferred gas content was found significantly larger than that seen in 21-cm emission measurements of H~I. In this paper we test the hypothesis that the apparent excess `dark’ gas is cold H~I, which would be evident in absorption but not in emission due to line saturation. The results show there is not enough 21-cm absorption toward the clouds to explain the total amount of `dark’ gas.

Read this paper on arXiv…

W. Reach, C. Heiles and J. Bernard
Tue, 15 Nov 16
1/86

Comments: accepted to Astrophysical Journal