Search for Correlations of High-energy Neutrinos Detected in IceCube with Radio-bright AGN and Gamma-Ray Emission from Blazars

Abstract

The IceCube Neutrino Observatory sends realtime neutrino alerts with a high probability of being astrophysical in origin. We present a new method to correlate these events and possible candidate sources using 2089 blazars from the Fermi-LAT 4LAC-DR2 catalog and with 3413 active galactic nuclei (AGNs) from the Radio Fundamental Catalog. No statistically significant neutrino emission was found in any of the catalog searches. The result suggests that a small fraction, <1%, of the studied AGNs emit neutrinos that pass the alert criteria, and is compatible with prior evidence for neutrino emission presented by IceCube and other authors from sources such as TXS 0506 + 056 and PKS 1502 + 106. We also present cross-checks to other analyses that claim a significant correlation using similar data samples.

IceCat-1: The IceCube Event Catalog of Alert Tracks

“…We have also explored the correlation of IceCube alerts with sources from very high energy gamma-ray and X-ray catalogs and find them consistent with chance expectation. Future IceCube analyses will more systematically explore the correlation of these alerts with blazars, as well as with other IceCube data on long and short timescales (Abbasi et al 2021d(Abbasi et al , 2023b.…”

“…Using a variety of data samples, IceCube continues to conduct searches for long-term neutrino emission and for correlations of neutrino data with known astrophysical objects across different wavelengths (Aartsen et al 2017c(Aartsen et al , 2019(Aartsen et al , 2020bAbbasi et al 2022c). For the 275 neutrino events in this catalog, we are performing several follow-up analyses that are the subject of ongoing and recent publications (Abbasi et al 2023a(Abbasi et al , 2023b. In this work, we report the results of a time-independent search for spatial correlations between the best-fit positions of the alerts and of sources from five catalogs of gamma-ray and X-ray sources.…”

Origin of high-energy astrophysical neutrinos: new results and prospects

“…Reconstructed arrival directions and energies of previously published events changed, in some cases significantly; many new events have also been added. Using this catalog for the analysis similar to [14], with direct application of the criteria from [14], results in the decrease [28] of the significance of associations between neutrinos and radio blazars compared to the original work, see discussion below in Sec. 3.4.…”

“…As we noted in Sec. 3.1.1, the significance of associations between IceCube neutrinos with energies above 200 TeV and VLBI blazars decreases [28] when the new reconstruction [5] is used, compared to Ref. [14], which used the originally published arrival directions and energies.…”

Searches for Neutrinos in the Direction of Radio-bright Blazars with the ANTARES Telescope

“…In addition, the recent publication of the IceCube Event Catalog of Alert Tracks-1 Abbasi et al (2023c), containing a revised sample of neutrino candidates with a high probability of being of astrophysical origin, has been followed by a search Abbasi et al (2023d) for a correlation with the population of blazars contained in the Fermi 4LAC-DR2 catalog and the Radio Fundamental Catalog. As no significant correlation is found, this result mitigates the previous findings of Plavin et al (2020) and indicates that only a minority of the γ-raybright and radio-bright AGN population can be identified as potential sources of high-energy neutrinos.…”