Tracing the merger rate of the Universe with APERTIF and ASKAP

TL;DR

This paper discusses how upcoming wide-field radio surveys with APERTIF and ASKAP can measure the universe's merger rate by detecting OH maser galaxies up to redshift 1.4, informing galaxy evolution models.

Contribution

It presents the first detailed prospects for all-sky blind surveys of OH maser galaxies using APERTIF and ASKAP, including expected detection numbers and constraints on the merger rate.

Findings

Potential to detect numerous OH maser galaxies up to redshift 1.4

Ability to constrain the OH maser luminosity function

Estimation of the merger rate evolution over cosmic time

Abstract

OH maser emission at 1.67 GHz is known to be associated with regions of intense star formation within ULIRGs. As these galaxies are formed through violent mergers, studying the co-moving density of OH maser galaxies across cosmic time will allow the merger rate of the Universe to be determined in an independent way. This merger rate is an important parameter in galaxy formation and evolution scenarios. The sensitivity, wide field of view and spectral coverage of both APERTIF on the WSRT and ASKAP will allow for the first time all-sky blind surveys for OH maser galaxies to be carried out to redshift 1.4. We describe the prospects for such surveys, including the expected number of OH maser galaxies that will be discovered, and what limits can be placed on the OH maser luminosity function, and hence the merger rate out to redshift 1.4 with various survey strategies.