Searches for steady neutrino emission from 3FHLblazars using eight years of IceCube data from the Northern hemisphere

TL;DR

This study used eight years of IceCube data to search for steady neutrino emission from 3FHL blazars, finding no significant excess and setting limits on their neutrino production.

Contribution

It presents the first stacking analysis of 3FHL blazars with IceCube data, establishing new limits on their neutrino emission.

Findings

No significant neutrino excess from blazars was observed.

First limits on neutrino production from 3FHL blazars were established.

Analysis covered 1301 blazars over 8 years of IceCube data.

Abstract

Located at the South Pole, the IceCube Neutrino Observatory is the world largest neutrino telescope, instrumenting one cubic kilometre of Antarctic ice at a depth between 1450m to 2450m. In 2013 IceCube reported the first observations of a diffuse astrophysical high-energy neutrino flux. Although the IceCube Collaboration has identified more than 100 high-energy neutrino events, the origin of this neutrino flux is still not known. Blazars, a subclass of Active Galactic Nuclei and one of the most powerful classes of objects in the Universe, have long been considered promising sources of high energy neutrinos. A blazar origin of this high-energy neutrino flux can be examined using stacking methods testing the correlation between IceCube neutrinos and catalogs of hypothesized sources. Here we present the results of a stacking analysis for 1301 blazars from the third catalog of hard \textit{Fermi}-LAT sources (3FHL). The analysis is performed on 8 years of through-going muon data from the Northern Hemisphere, recorded by IceCube between 2009 and 2016. No excess of neutrinos from the blazar position was found and first limits on the neutrino production of these sources will be shown.