Far-infrared selected star formation regions

Detailed far-IR observations and complementary submillimeter, 5 GHz continuum and C(O-18) observations of a sample of eight far-IR selected luminous regions of star formation are presented. The observations show that the sources of luminosity coincide with density peaks in the molecular clouds and that the exciting stars lie deep within these condensations. The far-IR sources have diversely shaped 40-180 micron spectra even though their 60-100 micron color temperatures are similar. The radio and far-IR results together show that the exciting stars are in clusters containing either zero-age main-sequence and pre-main-sequence stars or consisting entirely of pre-main-sequence objects. C(O-18) and submillimeter observations imply gas densities approximately 100,000-high enough to make T(dust) approximately T(gas).