Star formation properties of sub-mJy radio sources

TL;DR

This study analyzes the star formation properties of approximately 800 radio sources across a wide redshift range, comparing infrared and radio-derived SFRs, and explores the potential of deep radio surveys to trace cosmic star formation history.

Contribution

It demonstrates that radio power reliably traces star formation in both SFGs and RQ AGNs across redshifts, and assesses the role of starburst activity and AGN occurrence in radio sources.

Findings

Radio power is a good SFR tracer for SFGs and RQ AGNs.

No significant deviation of radio SFR indicator with redshift.

Deep radio surveys can effectively study cosmic star formation history.

Abstract

We investigate the star formation properties of ~800 sources detected in one of the deepest radio surveys at 1.4 GHz. Our sample spans a wide redshift range (~0.1 - 4) and about four orders of magnitude in star formation rate (SFR). It includes both star forming galaxies (SFGs) and active galactic nuclei (AGNs), further divided into radio-quiet and radio-loud objects. We compare the SFR derived from the far infrared luminosity, as traced by Herschel, with the SFR computed from their radio emission. We find that the radio power is a good SFR tracer not only for pure SFGs but also in the host galaxies of RQ AGNs, with no significant deviation with redshift or specific SFR. Moreover, we quantify the contribution of the starburst activity in the SFGs population and the occurrence of AGNs in sources with different level of star formation. Finally we discuss the possibility of using deep radio survey as a tool to study the cosmic star formation history.