A high-resolution 21 centimeter line study of infrared cirrus
G. Joncas, F. Boulanger, P. E. Dewdney;
ApJ, 1992, 397, 165
ABSTRACT:High-resolution H I observations of part of an IR cirrus in Ursa Major are discussed.
The atomic hydrogen component presents an intricate
morphology and velocity field.
The H I feature is made up of interconnecting
filaments and condensations the majority of which have an east-west
alignment.
Two filaments extrude perpendicularly from the main body of the
feature.
The vast majority of the H I spectra have multiple components with FWHM of
the order of 3-5 km/s.
The velocity dispersions are about equal to the
Alfven speed.
The turbulent and magnetic pressures are the main forces
acting on the H I gas.
In IR maps, the atomic cloud appears spatially connected
to a molecular cloud with a gas density one order of magnitude larger and a
turbulent energy one order of magnitude smaller.
The association and the
location of the whole object within a large H I loops suggests that a molecular
cloud is being formed or disrupted.
KEYWORDS: far infrared radiation, h i regions, infrared astronomy satellite, interstellar matter, sky surveys (astronomy), astronomical spectroscopy, carbon monoxide, high resolution, molecular clouds
PERSOKEY:ursa major, cirrus, h_i, 21 cm, ,
CODE: joncas92