In:
Proceedings of the International Astronomical Union, Cambridge University Press (CUP), Vol. 2, No. S237 ( 2006-08), p. 363-367
Abstract:
H I 21cm-line self-absorption (HISA) reveals the shape and distribution of cold atomic clouds in the Galactic disk. Many of these clouds lack corresponding CO emission, despite being colder than purely atomic gas in equilibrium models. HISA requires background line emission at the same velocity, hence mechanisms that can produce such backgrounds. Weak, small-scale, and widespread absorption is likely to arise from turbulent eddies, while strong, large-scale absorption appears organized in cloud complexes along spiral arm shocks. In the latter, the gas may be evolving from an atomic to a molecular state prior to star formation, which would account for the incomplete HISA-CO agreement.
Type of Medium:
Online Resource
ISSN:
1743-9213
,
1743-9221
DOI:
10.1017/S1743921307001731
Language:
English
Publisher:
Cambridge University Press (CUP)
Publication Date:
2006
detail.hit.zdb_id:
2170724-8
detail.hit.zdb_id:
232923-2
SSG:
16,12
