AGN and Starburst Galaxies Seen through Radio Surveys

Abstract

The emergence of a new population of radio galaxies at mJy and sub-mJy levels is responsible for the change in the slope of the radio source counts. This population seems to include both star forming galaxies and classical (AGN-powered) radio sources, but the relative importance of the two classes is still debated. We present results from the ATESP radio survey and its optical follow-up and show that the fraction of starburst galaxies changes from ~15% at fluxes >1 mJy to >50% at lower fluxes.

6 pages and 3 ps figures. To be published in Proc. of the Conference "the New Era of Wide-Field Astronomy", held in Preston (UK), 21-24 August 2000