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Disk Stability and Star Formation in Galaxy Disks
  Astronomy and astrophysics

Friday 31 January 2014
from 10:30 to 11:30
at FA31
Speaker : Kyle Westfall (Kapteyn Astronomical Institute)
Abstract : Based on gaseous and stellar kinematic data from the DiskMass Survey, I will discuss the relationship between the large-scale dynamical properties of late-type galaxy disks and their star-formation activity. Among other similar studies, ours is the first to use stellar velocity dispersions observed in the cold regime of galaxy disks to measure both mass surface density and disk stability via dynamical equations. Using disk-averaged quantities, we find that the star-formation-rate surface density is correlated with the stellar mass surface density and anti-correlated with the two-component (gas+stars) disk stability. We show that this anti-correlation can be predicted using a closed set of empirical scaling relations, implying that it is reflected in other statistical properties of star-forming galaxies. Finally, our data are consistent with an equilibrium scenario derived assuming star formation occurs in the gravitationally bound clouds of a multiphase interstellar medium that is in thermal and dynamical pressure balance. Given their influence on the gravitational field perpendicular to the disk, these results demonstrate that large-scale properties, like stellar and dark-matter mass density, affect the star-formation process in galaxy disks.

AlbaNova  | Last modified 05 December 2017 10:07  |  HELP