A MeerKAT search for persistent radio sources towards twenty-five localised Fast Radio Bursts

TL;DR

This study used MeerKAT to search for persistent radio sources near 25 localized fast radio bursts, detecting 14 sources and providing insights into their environments, but definitive classification requires further high-resolution observations.

Contribution

First systematic MeerKAT search for PRSs at FRB locations, providing flux measurements, variability analysis, and potential optical/X-ray associations to inform FRB progenitor models.

Findings

Detected 14 radio sources associated with FRB locations.

Observed flux variability in one radio source.

Found optical/X-ray excesses in several sources.

Abstract

The discovery of persistent radio sources (PRSs) associated with repeating fast radio bursts (FRBs) has shed light on the immediate environments and possible progenitors of these FRBs. The confirmed PRSs may support the theory that FRB progenitors are compact central engines, whilst the non-detections suggest diversity of FRB's local environment. We perform a subarcsecond-resolution MeerKAT search at 1.28 GHz on 25 well-localised FRB positions provided by ASKAP and MeerTRAP. We detect 14 radio sources and provide flux upper limits for 12 non-detections (both these numbers include a source that was detected during two epochs of observation, and not detected during one epoch, adding up to 26). One radio source shows variability as seen in flux variations over three epochs of observation. Archival optical data reveal excesses in the direction of 13 detected radio sources. Similarly for four sources in the X-ray band, with one possibly being a high-energy signature of a radio galaxy core. Since we cannot definitively classify our detected radio sources as PRSs, future high-resolution observations with e-MERLIN will be required to resolve the radio emission and pronounce on the presence of compact PRSs associated with the 14 detected sources presented here.