A Radio-quiet AGN as a candidate counterpart to neutrino event IceCube-200615A

TL;DR

This study investigates a radio-quiet AGN as a potential source of a specific IceCube neutrino event, using multiwavelength observations and spectral analysis to assess its likelihood as the neutrino emitter.

Contribution

The paper presents the identification of a plausible radio-quiet AGN counterpart to a neutrino event, supporting the possible link between such AGN and high-energy neutrinos.

Findings

The candidate AGN has a 87.5% probability of being the neutrino source.

The source's predicted neutrino flux is low but still consistent with being a neutrino emitter.

Radio-quiet AGN are statistically more likely to be associated with IceCube neutrino events.

Abstract

Follow-up observations of neutrino events have been a promising method for identifying sources of very-high-energy cosmic rays. Neutrinos are unambiguous tracers of hadronic interactions and cosmic rays. On June 15, 2020, IceCube detected a neutrino event with an 82.8% probability of being astrophysical in origin. To identify the astrophysical source of the neutrino, we used X-ray tiling observations to identify potential counterpart sources. We performed additional multiwavelength follow-up with NuSTAR and the VLA in order to construct a broadband spectral energy distribution (SED) of the most likely counterpart. From the SED, we calculate an estimate for the neutrinos we expect to detect from the source. While the source does not have a high predicted neutrino flux, it is still a plausible neutrino emitter. It is important to note that the other bright X-ray candidate sources consistent with the neutrino event are also radio-quiet AGN. A statistical analysis shows that 1RXS J093117.6+033146 is the most likely counterpart (87.5%) if the neutrino is cosmic in origin and if it is among X-ray detectable sources. This results adds to previous results suggesting a connection between radio-quiet AGN and IceCube neutrino events.