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arXiv · 2403.03752

Two 100 TeV neutrinos coincident with the Seyfert galaxy NGC 7469

Giacomo Sommani·Anna Franckowiak·Massimiliano Lincetto·Ralf-Jürgen Dettmar
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Abstract

In 2013, the IceCube collaboration announced the detection of a diffuse high-energy astrophysical neutrino flux. The origin of this flux is still largely unknown. The most significant individual source is the close-by Seyfert galaxy NGC 1068 at 4.2-sigma level with a soft spectral index. To identify sources based on their counterpart, IceCube releases realtime alerts corresponding to neutrinos with a high probability of astrophysical origin. We report here the spatial coincidence of two neutrino alerts, IC220424A and IC230416A, with the Seyfert galaxy NGC 7469 at a distance of 70 Mpc. We evaluate, a-posteriori, the chance probability of such a coincidence and discuss this source as a potential neutrino emitter based on its multi-wavelength properties and in comparison to NGC 1068 by performing a Goodness-of-Fit test. The test statistic is derived from a likelihood ratio that includes the neutrino angular uncertainty and the source distance. We apply this test first to a catalog of AGN sources and second to a catalog of Seyfert galaxies only. Our a-posteriori evaluation excludes the possibility of an accidental spatial coincidence of both neutrinos with the Seyfert galaxy NGC 7469 at 3.2-sigma level, leaving open the possibility that either one or both neutrinos originated from the source. To be compatible with non-detections of TeV neutrinos, the source would need to have a hard spectral index.

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Giacomo Sommani, Anna Franckowiak, Massimiliano Lincetto, Ralf-Jürgen Dettmar. 2024-03-06. Two 100 TeV neutrinos coincident with the Seyfert galaxy NGC 7469. https://doi.org/10.3847/1538-4357%2Fadb031

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