Abstract

Contributed Talk - Splinter Multimessenger

Friday, 13 September 2024, 15:15   (S25)

A Census and Follow-up Observations of Variable and Transient Radio Sources within Southern-Hemisphere IceCube Neutrino Fields

Florian Rösch [1,2], Etienne Bonnassieux [1], Roger Deane [3], Philip G. Edwards [4], Florian Eppel [1,2], Anna Franckowiak [5], Jonas Heßdörfer [1,2], Matthias Kadler [1], Karl Mannheim [1], Hrishikesh Shetgaonkar [1], Giacomo Sommani [5]
[1] JMU Würzburg, [2] MPI für Radioastronomie, [3] University of the Witwatersrand, [4] CSIRO Space and Astronomy, [5] Ruhr-Universität Bochum

The origin of high-energy cosmic neutrinos detected by the IceCube observatory is a hotly debated topic in astroparticle physics. There are multiple candidate source classes which can accelerate cosmic particles to the energies required to emit high-energy cosmic neutrinos and which have in common that they lead to variable/transient radio emissions. Recent observational results suggest that high-energy neutrinos may be associated with individual AGN jets. In this talk, we will present new results on selected candidate neutrino blazars from the Southern-Hemisphere TANAMI VLBI program. Aside from some promising associations with bright AGN, the bulk of the diffuse IceCube neutrino flux must be emitted from a rather faint and numerous source population. The sub-mJy low-frequency radio sky may harbor these neutrino emitters that have gone unnoticed in previous searches. On July 16th 2024, IceCube reported on two track-like neutrino events in spatial coincidence with each other and with the cascade-like neutrino event IC240714A. We observed the overlap of the 90% uncertainty regions of all three neutrino events with MeerKAT at 816 MHz, to perform a census of variable and transient radio sources that could have produced all three detected neutrinos. Here, we present first results of this MeerKAT census of variable and transient faint radio sources in this IceCube multiplet neutrino field.