... Research . ... Most of my work has concentrated on nearby galaxies; their structure, stellar and dust content, and the distribution of mass within them, and putting these measurements in the context hierarchical galaxy formation models. I am currently leading the GHOSTS Survey , a large HST survey of the resolved stelllar populations of bulges, thick disks, and halos of nearby, massive disk galaxies. ... What regulates star formation in disk galaxies? ... OSU Bright Galaxy Survey . ...