A Distant Fast Radio Burst Associated to its Host Galaxy with the Very Large Array

TL;DR

This paper reports the discovery and precise localization of a new Fast Radio Burst with the highest dispersion measure to date, associating it with a pair of potential host galaxies at redshift ~0.6, and analyzing its properties and environment.

Contribution

It presents the first subarcsecond localization of a high-DM FRB and identifies its potential host galaxies, advancing understanding of FRB origins and environments.

Findings

Highest DM of any localized FRB at 959 pc/cm3

No repeat detection in extensive follow-up observations

Association with a pair of galaxies at z~0.6

Abstract

We present the discovery and subarcsecond localization of a new Fast Radio Burst with the Karl G. Jansky Very Large Array and realfast search system. The FRB was discovered on 2019 June 14 with a dispersion measure of 959 pc/cm3. This is the highest DM of any localized FRB and its measured burst fluence of 0.6 Jy ms is less than nearly all other FRBs. The source is not detected to repeat in 15 hours of VLA observing and 153 hours of CHIME/FRB observing. We describe a suite of statistical and data quality tests we used to verify the significance of the event and its localization precision. Follow-up optical/infrared photometry with Keck and Gemini associate the FRB to a pair of galaxies with $\rm{r}\sim23$ mag. The false-alarm rate for radio transients of this significance that are associated with a host galaxy is roughly $3\times10^{-4}\ \rm{hr}^{-1}$. The two putative host galaxies have similar photometric redshifts of $z_{\rm{phot}}\sim0.6$, but different colors and stellar masses. Comparing the host distance to that implied by the dispersion measure suggests a modest (~ 50 pc/cm3) electron column density associated with the FRB environment or host galaxy/galaxies.