A Radio View of the Sky: the Cosmic History of Star-Forming and AGN Galaxies

Abstract

We explore the cosmic evolution of radio detected star forming (SF) galaxies and active galactic nuclei (AGN), drawn from the VLA-COSMOS survey, out to z = 1.3. We present the 20 cm radio luminosity function for these populations, and find that SF galaxies evolve much more rapidly than low-power radio AGN. Our results imply that weak radio AGN (L_(1.4GHz) ≤ 5×10^(25) WHz^(−1)) occur in the most massive galaxies already at z ~ 1. They may significantly contribute to the heating of their surrounding medium and thus inhibit gas accretion onto their host galaxies, as recently suggested for the 'radio mode' AGN feedback in cosmological models.

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