Vertical distribution and support of Galactic H I
F. J. Lockman, C. S. Gehman;
ApJ, 1991, 382, 182
ABSTRACT:The shape of high-latitude 21-cm H I emission profiles suggests that the local neutral interstellar
medium is supported in the Galactic gravitational potential primarily by
turbulence, that is, by the motion of individual clouds.
Composite H I spectra
derived from averages over large areas of the high-latitude sky are modeled by
several isothermal components whose equlibrium vertical distribution in a
plausible Galactic potential successfully reproduces the observed thickness
of the H I layer.
The analysis implies that there are several H I
populations with differing central density, velocity dispersion, and scale
height although they cannot be characterized with precision.
The kinetic
energy in bulk vertical motions is more than about 6 x 10 exp 51 ergs/sq kpc for a
full disk.
About 10 percent of the local H I is not part of a relaxed
distribution but is infalling or is in ordered flows.
KEYWORDS: emission spectra, galactic structure, hydrogen, interstellar gas, milky way galaxy, astronomical models, computational astrophysics, radio sources (astronomy)
PERSOKEY:h_i, 21 cm, milky way, ,
CODE: lockman91