The Far-Infrared Radio Correlation at High-z: Prospects for the SKA

TL;DR

This paper discusses how the Far-Infrared--radio correlation evolves with redshift due to cosmic-ray cooling processes, highlighting the potential of high-frequency radio observations with SKA to measure star formation in distant galaxies.

Contribution

It summarizes predictions for the evolution of the FIR-radio correlation at high redshift and explores implications for future SKA surveys.

Findings

Radio continuum at ~10 GHz can effectively trace star formation at high redshift.

Inverse Compton scattering off the CMB suppresses non-thermal radio emission with increasing redshift.

High-frequency radio measurements are less affected by dust obscuration.

Abstract

In this conference proceedings article I summarize the recent work of Murphy (2009) which presents physically motivated predictions for the evolution of the Far-Infrared--radio correlation as a function of redshift arising from variations in the cosmic-ray (CR) electron cooling time-scales as Inverse Compton (IC) scattering off of the Cosmic Microwave Background (CMB) becomes increasingly important. Since the non-thermal component of a galaxy's radio continuum is increasingly suppressed with redshift, radio continuum measurements at moderately high frequency ($\sim$10 GHz) become one of the cleanest ways to quantify the star formation activity of galaxies at high redshifts unbiased by dust. Given the focus of the conference, extra emphasis placed on what this may mean for deep radio continuum surveys using next generation radio facilities such as the Square Kilometer Array (SKA).