Radio Properties of the Quasar J1718+4239, the Proposed Source of the Neutrino Event IceCube-201221A

Abstract

NVSS J171822+423948 was recently identified as the most probable counterpart of the neutrino event IC-201221A. Based on the highly variable γ-ray, optical, and mid-infrared emission, the dates of the flaring events, and optical spectroscopy in the field of interest, this object was classified as a neutrino-emitting blazar candidate. Since its radio properties were not discussed in detail, we present archival observations. High-amplitude total radio flux density variability supports the connection between the flares at higher energies and the neutrino event.