Eight Billion Years of Disk Galaxy Evolution: No galaxy is an island

Abstract

We present a brief discussion of the evolution of disk galaxy stellar masses, sizes, rotation velocities, and star formation rates over the last eight billion years. Recent observations have failed to detect significant evolution in the stellar mass Tully-Fisher relation, stellar mass–size relation, and the stellar mass function of disk galaxies. Yet, most z < 1 star formation is in disks, and this star formation would be expected to drive a rapid growth of the total stellar mass (and therefore mass function) of disks in the last eight billion years. Such a build-up is not seen; instead, a rapid build-up in the total stellar mass in non-star-forming spheroid-dominated galaxies is observed. Large numbers of disk-dominated galaxies are systematically shutting off their star formation and building up a spheroid (or losing a disk) in the epoch 0 < z < 1.