Evidence For A Correlation Between Astrophysical Neutrinos and Radio Flares

TL;DR

This study finds a significant correlation between radio flares observed in the VLASS survey and astrophysical neutrinos detected by IceCube, suggesting radio variability as a key electromagnetic counterpart to neutrino sources.

Contribution

It provides the first statistical evidence linking radio flares to astrophysical neutrinos and highlights the importance of radio observations in neutrino astronomy.

Findings

Radio flares contribute approximately 13% of observed astrophysical neutrinos.

Over 80% of neutrino-associated radio flares are not detected in gamma-ray or X-ray wavelengths.

Future VLASS data will likely increase the significance of radio-neutrino associations to over 3σ.

Abstract

We use data from the first two epochs of the Very Large Array Sky Survey (VLASS) and the IceCube Neutrino Observatory to search for evidence of a correlation between radio variability and the detection of astrophysical neutrinos. We find an excess number of associations between flaring radio sources and neutrinos that were detected between the first and second VLASS observations at $>2\sigma$ confidence. This excess is consistent with radio flares contributing $\sim13\,\%$ of the astrophysical neutrinos observed by IceCube. Notably $>80\,\%$ of the radio flares associated with neutrinos are not detected at either $\gamma$-ray or X-ray wavelengths, highlighting the importance of radio observations for identifying potential electromagnetic counterparts to astrophysical neutrinos. No excess in the number of associations between the wider radio-variable population and the IceCube neutrinos is seen when no time constraint is placed on the neutrino detection. We predict that data from future VLASS epochs will see an excess number of associations between radio flares and neutrinos at the $>3\sigma$ level, and expected improvements to the positional constraints on the neutrinos may increase that confidence to $>5\sigma$, should our results be representative.