\hi clouds, \hi spin temperatures
H. S. Liszt;
ApJ, 1983, 275, 163
ABSTRACT:The 21-cm H I lines have three related observational aspects: good spin temperature correlation at high latitudes with
optical depth, the suggestion of a ubiquitous intercloud component that is
incompatible with observations of other species, and emission lines that are
broader than their associated absorption profiles.
The first of these can be
reproduced by introducing a column density-spin temperature correlation into
uniform cloud models.
The intercloud medium can be reproduced by putting hot
skins around absorbing cloud cores, in the mode of the McKee-Ostriker (1977)
model of the interstellar medium.
The disparate line widths of emission and
absorption features require cloud models in which the gas temperature varies
substantially and continuously across a given cloud.
KEYWORDS: abundance, centimeter waves, h lines, hydrogen clouds, radio sources (astronomy), spectral line width, astronomical models, electron spin, gas density, gas temperature, high temperature gases, optical thickness, spin temperature
PERSOKEY:h_i, ,
CODE: liszt83