The radio properties of quasi-periodic X-ray eruption sources

TL;DR

This study investigates the radio emissions of 12 quasi-periodic X-ray eruption sources, revealing weak, compact radio sources with no strong jets, suggesting a link to recent tidal disruption events rather than active galactic nuclei.

Contribution

It provides the first comprehensive radio property analysis of QPE sources, comparing them with TDEs and revealing their unique radio characteristics.

Findings

Weak, compact radio sources in 5/12 QPEs

No correlation between radio emission and X-ray QPEs

Radio properties consistent with recent TDEs rather than AGN activity

Abstract

Quasi-periodic X-ray eruptions (QPEs) are a new class of repeating nuclear transient in which repeating X-ray flares are observed coming from the nuclei of generally low mass galaxies. Here we present a comprehensive summary of the radio properties of 12 bona-fide quasi-periodic eruption sources, including a mix of known tidal disruption events (TDEs) and AGN-like hosts. We include a combination of new dedicated radio observations and archival/previously published radio observations to compile a catalogue of radio observations of each source in the sample. We examine the overall radio properties of the sample and compare to the radio properties of known TDEs, given the apparent link between QPEs and TDEs. Overall we find compact, weak radio sources associated with 5/12 of the QPE sources and no signatures of strong AGN activity via a luminous radio jet. We find no radio variability or correlation between radio emission and the X-ray QPE properties, implying that the mechanism that produces the X-ray flares does not generate strong radio-emitting outflows. The compactness of the radio sources and lack of correlation between radio luminosity and SMBH mass is very unusual for AGN, but the radio spectra and luminosities are consistent with outflows produced by a recent TDE (or accretion event), in both the known TDE sources as well as the AGN-like sources in the sample.