Self-consistent neutrino and UHE cosmic ray spectra from Mrk 421 [HEAP]

http://arxiv.org/abs/1310.7923


We examine the neutrino and cosmic ray spectra resulting from two models of fitting the spectral energy distribution (SED) of the blazar Mrk~421 using a self-consistent leptohadronic code. The $\gamma$-ray emission is attributed to either synchrotron radiation of ultra-high energy protons (LHs model) or to synchrotron radiation from electrons that result from photopion interactions of lower energy protons (LH$\pi$ model). Although both models succeed in fitting satisfactorily the SED, the parameter values that they use result in significantly different neutrino and cosmic-ray spectra. For the LH$\pi$ model, which requires high proton energy density, we find that the neutrino spectrum peaks at an energy $E_{\rm \nu,peak}= 3.3$ PeV which falls well within the energy range of recent neutrino observations. While at the same time its peak flux is just under the sensitivity limit of IC-40 observations, it cannot produce ultra-high energy cosmic rays. In the LHs model, on the other hand, neutrinos are far from being detectable because of their low flux and peak energy at $E_{{\rm \nu,peak}} \simeq 100$ PeV. However, the propagation of protons produced by the decay of escaping neutrons results in an ultra-high energy cosmic ray flux close to that observed by Pierre Augere, HiRes and Telescope Array at energies $E_p \simeq 30$ EeV.

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Date added: Wed, 30 Oct 13