November 12, 1998 CfA Colloquium

Title: Recipes for Global Star Formation in Galaxies

Speaker: Rob Kennicutt

Abstract: Galaxies exhibit an enormous range in star formation activity, over a factor of a million even when normalized per unit area or mass, This range extends from quiescent galaxies with star formation timescales longer than the Hubble time, to extreme starburst galaxies, with star formation rates (SFRs) that are limited only by the finite dynamical timescale for gas accretion. A key challenge for galaxy formation and evolution modelling is to construct a parametrization or "recipe" relating the SFR to the properties of the interstellar medium, that can reproduce this vast range in activities. This talk will review the range of star formation properties found in nearby galaxies and starbursts, and describe a project aimed at defining the empirical form of the global star formation law. Two simple recipes, a Schmidt law and an equally simple kinematical model, provide remarkably good fits to the observed SFRs, extending over 5-6 orders of magnitude in SFR and gas density.

Reference for students: Kennicutt, R.C. 1998, ARAA, 36, 189. Also available as astro-ph/9807187 Lunch on Thursday at 1pm in the classroom.