In:
Proceedings of the International Astronomical Union, Cambridge University Press (CUP), Vol. 11, No. S315 ( 2015-08)
Abstract:
We have mapped cold atomic gas in 21cm line H i self-absorption (HISA) at arcminute resolution over more than 90% of the Milky Way's disk. To probe the formation of H 2 clouds, we have compared our HISA distribution with CO J = 1-0 line emission. Few HISA features in the outer Galaxy have CO at the same position and velocity, while most inner-Galaxy HISA has overlapping CO. But many apparent inner-Galaxy HISA-CO associations can be explained as chance superpositions, so most inner-Galaxy HISA may also be CO-free. Since standard equilibrium cloud models cannot explain the very cold H i in many HISA features without molecules being present, these clouds may instead have significant CO-dark H 2 .
Type of Medium:
Online Resource
ISSN:
1743-9213
,
1743-9221
DOI:
10.1017/S1743921316007882
Language:
English
Publisher:
Cambridge University Press (CUP)
Publication Date:
2015
detail.hit.zdb_id:
2170724-8
SSG:
16,12