Star Formation in Disks and Spheroids

Theoretical models of the star-formation process in disk and spheroidal galaxies are reviewed. Consideration is given to the irregularity and sensitivity to external perturbations of star formation in disks, the apparent lack of star formation in spheroids (suggesting that spheroid stars actually formed earlier, in disks), and globular-cluster properties with implications for the earliest phases of galactic evolution. A brief outline of the galaxy formation process is given, including the initial unhindered collapse of condensations, the emergence of progressively larger star-formation regions resembling compact dwarf galaxies, globular-cluster formation, and the evolution of larger structures in collisions of star-forming systems.