TY - JOUR
T1 - Hidden Cores of Active Galactic Nuclei as the Origin of Medium-Energy Neutrinos
T2 - Critical Tests with the MeV Gamma-Ray Connection
AU - Murase, Kohta
AU - Kimura, Shigeo S.
AU - Meszaros, Peter Istvan
N1 - Funding Information:
We thank Francis Halzen and Ali Kheirandish for discussion about NGC 1068. K. M. acknowledges the invitation to the AMEGO Splinter meeting at the 233rd AAS meeting (held in Seattle USA), where preliminary results were presented. This work is supported by Alfred P. Sloan Foundation, NSF Grants No. PHY-1620777 and No. AST-1908689, and JSPS KAKENHI No. 20H01901 (K. M.), JSPS Oversea Research Fellowship, IGC Fellowship, JSPS Research Fellowship, and JSPS KAKENHI No. 19J00198 (S. S. K.), NASA NNX13AH50G, and Eberly Foundation (P. M.).
Publisher Copyright:
© 2020 American Physical Society.
PY - 2020/7/3
Y1 - 2020/7/3
N2 - Mysteries about the origin of high-energy cosmic neutrinos have deepened by the recent IceCube measurement of a large diffuse flux in the 10-100 TeV range. Based on the standard disk-corona picture of active galactic nuclei (AGN), we present a phenomenological model enabling us to systematically calculate the spectral sequence of multimessenger emission from the AGN coronae. We show that protons in the coronal plasma can be stochastically accelerated up to PeV energies by plasma turbulence, and find that the model explains the large diffuse flux of medium-energy neutrinos if the cosmic rays carry only a few percent of the thermal energy. We find that the Bethe-Heitler process plays a crucial role in connecting these neutrinos and cascaded MeV gamma rays, and point out that the gamma-ray flux can even be enhanced by the reacceleration of secondary pairs. Critical tests of the model are given by its prediction that a significant fraction of the MeV gamma-ray background correlates with ∼10 TeV neutrinos, and nearby Seyfert galaxies including NGC 1068 are promising targets for IceCube, KM3Net, IceCube-Gen2, and future MeV gamma-ray telescopes.
AB - Mysteries about the origin of high-energy cosmic neutrinos have deepened by the recent IceCube measurement of a large diffuse flux in the 10-100 TeV range. Based on the standard disk-corona picture of active galactic nuclei (AGN), we present a phenomenological model enabling us to systematically calculate the spectral sequence of multimessenger emission from the AGN coronae. We show that protons in the coronal plasma can be stochastically accelerated up to PeV energies by plasma turbulence, and find that the model explains the large diffuse flux of medium-energy neutrinos if the cosmic rays carry only a few percent of the thermal energy. We find that the Bethe-Heitler process plays a crucial role in connecting these neutrinos and cascaded MeV gamma rays, and point out that the gamma-ray flux can even be enhanced by the reacceleration of secondary pairs. Critical tests of the model are given by its prediction that a significant fraction of the MeV gamma-ray background correlates with ∼10 TeV neutrinos, and nearby Seyfert galaxies including NGC 1068 are promising targets for IceCube, KM3Net, IceCube-Gen2, and future MeV gamma-ray telescopes.
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U2 - 10.1103/PhysRevLett.125.011101
DO - 10.1103/PhysRevLett.125.011101
M3 - Article
C2 - 32678637
AN - SCOPUS:85087949033
SN - 0031-9007
VL - 125
JO - Physical review letters
JF - Physical review letters
IS - 1
M1 - 011101
ER -