A composite large-scale CO survey at high galactic latitudes in the second quadrant
A. Heithausen, J. G. Stacy, H. W. De Vries, U. Mebold, P. Thaddeus;
AaA, 1993, 268, 265
ABSTRACT:Surveys undertaken in the 2nd quadrant of the Galaxy with the CfA 1.2 m telescope have been combined to produce a map covering about 620 sq deg in the 2.6 mm
CO(J = 1 - 0) line at high galactic latitudes.
There is CO emission from
molecular 'cirrus' clouds in about 13 percent of the region surveyed.
The CO
clouds are grouped together into three major cloud complexes with 29
individual members.
All clouds are associated with infrared emission at 100
micron, although there is no one-to-one correlation between the
corresponding intensities.
CO emission is detected in all bright and dark Lynds'
nebulae cataloged in that region; however not all CO clouds are visible on
optical photographs as reflection or absorption features.
The clouds are
probably local.
At an adopted distance of 240 pc cloud sizes range from O.1 to 30
pc and cloud masses from 1 to 1600 solar masses.
The molecular cirrus
clouds contribute between 0.4 and 0.8 M solar mass/sq pc to the surface density
of molecular gas in the galactic plane.
Only 26 percent of the
'infrared-excess clouds' in the area surveyed actually show CO and about 2/3 of the clouds
detected in CO do not show an infrared excess.
KEYWORDS: interstellar matter, line spectra, molecular clouds, sky surveys (astronomy), carbon monoxide, infrared astronomy, mass distribution
CODE: heithausen93