Observational studies of the structure, content and environment of intermediate and high-mass star-forming regions

Abstract

This thesis describes observational studies of star-forming regions and their influence on the interstellar medium. First, in an effort to understand the factors that govern the transition from low-to high-mass star formation, a sample of intermediate-mass starforming regions (IM SFRs) is identified for the first time. IM SFRs constitute embedded clusters where stars up to-but not exceeding-∼ 8 M are being produced. They are at an early evolutionary stage akin to compact H II regions, but they lack the massive ionizing central star(s). IRAS colors, Spitzer Space Telescope mid-IR images, millimeter