Radio Supernovae in the Local Universe

TL;DR

This paper discusses the potential of radio sky surveys to discover more supernovae, understand stellar evolution, and aid in identifying electromagnetic counterparts to gravitational wave sources, emphasizing the importance for future radio facilities.

Contribution

It advocates for medium-area radio sky surveys at C-band or S-band to uncover hidden supernovae and support multi-messenger astronomy with upcoming radio telescopes.

Findings

Radio supernovae are undercounted due to optical obscuration.

A radio survey can reveal a larger supernova population.

Radio observations are crucial for multi-messenger astronomy.

Abstract

In the last three decades, about 50 radio supernovae have been detected as a result of targeted searches of optically discovered supernovae in the local universe. Despite this relatively small number some diversity among them has already been identified which is an indication of the underlying richness of radio supernovae waiting to be discovered. For example, comparison of star formation and supernova discovery rate imply that as many as half of the supernovae remain undetected in the traditional optical searches, either because of intrinsic dimness or due to dust obscuration. This has far reaching consequences to the models of stellar and galaxy evolution. A radio sky survey would be ideal to uncover larger supernova population. Transient radio sky would benefit significantly from such a survey. With the advent of advanced gravitational wave detectors a new window is set to open on the local Universe. Localization of these gravitational detectors is poor to identify electromagnetic counterparts of the gravitational wave sources. However, the longer lasting radio emission accompanied in these sources could be effectively identified in a radio sky survey. We advocate a medium area ($\approx$ a few thousand $\rm deg^{2}$) radio sky survey at C-band. Alternatively, a survey at S-band has advantage of larger sky coverage without serious loss of the science case as presented here. Understanding the background in radio sky will be of paramount importance for the upcoming sensitive radio facilities including the Square Kilometer Array.