Seminar by Alex Gurvich, Northwestern
Star forming galaxies (SFGs) are broadly split between dispersion dominated (“clumpy”) and rotation dominated (“disky”) and are thought to smoothly transition from the former to the latter through the process of “disk settling.” In this talk I will describe the results from a recent paper in which we track the evolution of three SFGs from the FIRE simulations which transition from kinematically hot and disordered states to kinematically cold galactic disks in order to investigate how and when disk settling occurs. We find that galactic disk settling occurs: 1) at around a fixed halo mass of 1012 solar masses (stellar mass ~3 x 1010 solar masses); 2) rapidly, i.e. over a short time compared to the Hubble time (1-2 Gyr); 3) at the same time that the galactic star formation rate becomes self-regulated (suggesting a link between the existence of a galactic disk and the ability of a galaxy to regulate its star formation rate); and 4) and at the same time outflows are confined to the ISM (which may be the proximate causal trigger). When taken as a whole, these results paint a straightforward picture of the fundamental milestones in the lifecycle of a SFG from clump to an extended thin disk.
Host: Greg Bryan