Diffuse flux of PeV neutrinos from centrifugally accelerated protons in active galactic nuclei

Abstract

Evidence for high-energy astrophysical PeV neutrinos has been found in the IceCube experiment from an analysis with a 7. 5-year (2010 -2017) data. Active galactic nuclei (AGN) are among the most prominent objects in the universe, and are widely speculated to be emitters of ultra-high-energy (UHE) cosmic rays with proton domination. Based on the standard two-step LLCD mechanism of particle acceleration, a transformation of energy occurs from AGN's central super-massive black hole (SMBH) rotation to high-energy protons. Protons can be accelerated up to ∼ 0.1 EeV energies and above, and might generate PeV neutrinos in the energy range 1-10 PeV through plausible hadronic interactions. The theoretically estimated revised extragalactic diffuse muon neutrino flux employing the 'luminosity-dependent density evolution (LDDE)' model for the AGN luminosity function (LF) is found consistent with the IceCube level if only a fraction, 6.56% of the total bolometric luminosity (BL) of AGN is being realizable to power the PeV neutrinos. In the Λ CDM cosmological framework with the LDDE modeled LF and photon index distribution, about 5.18% of the total BL is enough to power the IceCube neutrinos.