26-30 October 2015
Asia/Tokyo timezone

High-energy Particle Emission and Cumulative Background from Low-Luminosity Active Galactic Nuclei

29 Oct 2015, 17:55
Room 3.4 ()

Room 3.4

Oral presentation Neutrino physics Neutrinos


Dr Shigeo KIMURA (Tohoku University)


The origin of high-energy neutrinos detected by the IceCube neutrino telescope is a big mystery of high-energy astrophysics. We propose low-luminosity active galactic nuclei (LLAGNs) as a novel source of the high-energy neutrinos. The radiation inefficient accretion flows (RIAFs) are believed to exist in LLAGNs. The Coulomb collisions inside RIAFs is so inefficient that plasmas naturally have high-energy protons through the stochastic particle acceleration. We calculate spectra of escaping neutrinos and cosmic-ray (CR) protons, and find that the RIAFs in LLAGNs can accelerate protons up to ~ PeVs and emit TeV–PeV neutrinos via pp and/or pγ reactions. If ~ 1% of the accretion luminosity is carried away by non-thermal protons, the diffuse neutrino intensity from the RIAFs in LLAGN can be compatible with the observed IceCube data (Kimura, Murase & Toma 2015, ApJ, 806, 159). This result does not contradict either of the diffuse gamma-ray background observed by Fermi or observed diffuse CR flux. This model can be tested by gamma-ray observations around the cores of LLAGNs (e.g., Fujita, Kimura, Murase 2015, PRD, 92, 023001).

Primary author

Dr Shigeo KIMURA (Tohoku University)


Prof. Kenji Toma (Tohoku University) Prof. Kohta MURASE (The Pennsylvania State University) Prof. Yutaka FUJITA (Osaka University)

Presentation Materials