Active galactic nuclei (AGN) are promising candidate sources of high-energy astrophysical neutrinos, since they provide environments rich in matter and photon targets where cosmic-ray interactions may lead to the production of gamma rays and neutrinos. We searched for high-energy neutrino emission from AGN using the Swift-BAT Spectroscopic Survey catalog of hard X-ray sources and 12 yr of IceCube muon track data. First, upon performing a stacked search, no significant emission was found. Second, we searched for neutrinos from a list of 43 candidate sources and found an excess from the direction of two sources, the Seyfert galaxies NGC 1068 and NGC 4151. We observed NGC 1068 at flux ϕνμ+ν¯μ = 4.02-+1.521.58 × 10-11 TeV−1 cm−2 s−1 normalized at 1 TeV, with a power-law spectral index γ = 3.10-+0.220.26, consistent with previous IceCube results. The observation of a neutrino excess from the direction of NGC 4151 is at a posttrial significance of 2.9σ. If interpreted as an astrophysical signal, the excess observed from NGC 4151 corresponds to a flux ϕνμ+ν¯μ = 1.51-+0.810.99 × 10-11 TeV−1 cm−2 s−1 normalized at 1 TeV and γ = 2.83-+0.280.35

Search for Neutrino Emission from Hard X-Ray AGN with IceCube

Bernardini, E.;Boscolo Meneguolo, C.;Mancina, S.;
2025

Abstract

Active galactic nuclei (AGN) are promising candidate sources of high-energy astrophysical neutrinos, since they provide environments rich in matter and photon targets where cosmic-ray interactions may lead to the production of gamma rays and neutrinos. We searched for high-energy neutrino emission from AGN using the Swift-BAT Spectroscopic Survey catalog of hard X-ray sources and 12 yr of IceCube muon track data. First, upon performing a stacked search, no significant emission was found. Second, we searched for neutrinos from a list of 43 candidate sources and found an excess from the direction of two sources, the Seyfert galaxies NGC 1068 and NGC 4151. We observed NGC 1068 at flux ϕνμ+ν¯μ = 4.02-+1.521.58 × 10-11 TeV−1 cm−2 s−1 normalized at 1 TeV, with a power-law spectral index γ = 3.10-+0.220.26, consistent with previous IceCube results. The observation of a neutrino excess from the direction of NGC 4151 is at a posttrial significance of 2.9σ. If interpreted as an astrophysical signal, the excess observed from NGC 4151 corresponds to a flux ϕνμ+ν¯μ = 1.51-+0.810.99 × 10-11 TeV−1 cm−2 s−1 normalized at 1 TeV and γ = 2.83-+0.280.35
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11577/3555990
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