Far-infrared emission of molecular clouds
C. E. Ryter, J. L. Puget;
ApJ, 1977, 215, 775
ABSTRACT:The far-IR power released by interstellar matter on a galactic scale is evaluated using available IR observations of massive molecular clouds and of the
diffuse galactic radiation along with the distribution of interstellar
matter deduced from 2.6-mm CO observations.
An IR luminosity that is
normalized per hydrogen atom is defined, an interstellar-grain model is
outlined, and an attempt is made to relate the far-IR brightness of the 'cold'
envelope of nine IR sources to the column density of that envelope.
An average
normalized IR luminosity of approximately 2.1 by 10 to the -30th power W per H atom is
obtained for these sources, and the average value for the whole Galaxy is
suggested to be of the same order of magnitude.
It is concluded that the galactic
plane should exhibit a color temperature of the order of 23 K and that most
molecular clouds are associated with very powerful sources, the most likely
being newly formed stars within the clouds.
A global star-formation rate
per unit mass of interstellar matter is computed and compared with rates
derived from star counts.
KEYWORDS: far infrared radiation, hydrogen clouds, infrared astronomy, interstellar gas, stellar evolution, carbon monoxide, cosmic dust, galactic radiation, gas density, h lines, radiant flux density, star formation rate, stellar luminosity
CODE: ryter77