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

Journal article

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 = 4.02−1.52+1.58×10−11 TeV−1 cm−2 s−1 normalized at 1 TeV, with a power-law spectral index γ = 3.10 −0.22+0.26 , 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 = 1.51−0.81+0.99×10−11 TeV−1 cm−2 s−1 normalized at 1 TeV and γ = 2.83 −0.28+0.35 .

Authors: Abbasi, R; Ackermann, M; Adams, J; Agarwalla, SK; Aguilar, JA

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: American Astronomical Society
• Journal: The Astrophysical Journal
• Volume: 981
• Issue: 2
• Article number: 131
• Publication date: 2025-03-04
• Acceptance date: 2025-01-09
• DOI: 10.3847/1538-4357/ada94b
• EISSN: 1538-4357
• ISSN: 0004-637X
• Language: English
• Keywords: Active galaxies; High energy astrophysics; Neutrino astronomy; Seyfert galaxies