IceCube population constraints on neutrino emission by Fermi-LAT detected active galactic nuclei

TL;DR

This study uses 13 years of IceCube data to search for correlations between neutrino emissions and GeV-detected active galactic nuclei, setting new constraints on their contribution to high-energy astrophysical neutrinos.

Contribution

It introduces a more general and sensitive statistical analysis method to constrain neutrino emission from various subclasses of GeV-detected AGN, improving upon previous correlation assumptions.

Findings

No significant correlation found between neutrinos and GeV-detected AGN.

Stringent upper limits set on neutrino emission from AGN subclasses.

Constraints challenge models predicting high neutrino flux from these sources.

Abstract

Gamma-ray-bright active galactic nuclei (AGN) have been one of the most promising source classes of high-energy astrophysical neutrinos detected by IceCube. The first evidence of an IceCube point source was a blazar detected by the Fermi Large Area Telescope (LAT), TXS ~0506+056. Previous analyses have ruled out GeV-bright blazars as the predominant contributor to the high-energy astrophysical neutrino flux under simple correlation assumptions about the relationship between the fluxes of gamma rays and neutrinos. We present results from a more general and more sensitive search for correlation between neutrinos and GeV-selected AGN using improvements in the IceCube statistical methods and 13 years of data. We detect no correlation and set stringent constraints on neutrino emission by populations of GeV-detected AGN. These include constraints on the neutrino emission from subclasses of GeV-detected AGN, including BL Lacs, flat-spectrum radio quasars (FSRQ) and non-blazar AGN, using stacking analyses testing a variety of hypothesized relationships between neutrino and gamma-ray flux. We also present results from an analysis that is sensitive to a wider range of relationships between the gamma-ray and neutrino signal.