Simple Model of the Outflow from Starburst Galaxies: Application to Radio Observations

Abstract

We present an analytical model for the hydrodynamic outflow from the disk of a starburst galaxy. The model is used to calculate the cosmic-ray propagation and the radio intensity distribution in the nuclear starburst region of NGC 253. We find that the cosmic-ray energy production rate of the central 600 pc of NGC 253 is about 3×1041 ergs s-1, which is about 15% of the total mechanical supernova power. For this inner region, we estimate a terminal outflow velocity of 900 km s-1 and a mass-loss rate of M˙=2-4 Msolar yr-1.