Obscured Star Formation in the Host Galaxies of Superluminous Supernovae

TL;DR

This study uses radio observations to reveal obscured star formation in superluminous supernova host galaxies, showing many have high, dust-enshrouded star formation rates and a higher fraction of starburst activity than previously thought.

Contribution

It provides new radio-based measurements of star formation in SLSN hosts, highlighting obscured star formation and a higher prevalence of starburst galaxies among them.

Findings

Some SLSN hosts have high radio-derived SFRs exceeding optical estimates.

Obscured star formation is common in SLSN host galaxies.

A correlation between metallicity and extinction is observed.

Abstract

We present the results of 3 GHz radio continuum observations of the 8 host galaxies of super-luminous supernovae (SLSNe) at $0.1 < z < 0.3$ by using the Karl G. Jansky Very Large Array. Four host galaxies are detected significantly, and two of them are found to have high star-formation rates (SFRs $>$ 20 $M_{\odot}$ yr$^{-1}$) derived from radio emission, making them the most intensely star-forming host galaxies among SLSN host galaxies. We compare radio SFRs and optical SFRs, and find that three host galaxies have an excess in radio SFRs by a factor of $>$2, suggesting the existence of dust-obscured star formation, which cannot be traced by optical studies. Two of the three host galaxies, which are located in the galaxy main sequence based on optical SFRs, are found to be above the main sequence based on their radio SFRs. This suggests a higher fraction of starburst galaxies in SLSN hosts than estimated in previous studies. We calculate extinction from the ratio between radio SFRs and dust-uncorrected optical SFRs and find that the hosts are on the trend of increasing extinction with metallicity, which is consistent with the relation in local star-forming galaxies. We also place a constraint on a pulsar-driven SN model, which predicts quasi-steady synchrotron radio emission.