Neutrino and $\gamma$-ray Emission from the Core of NGC1275 by Magnetic Reconnection: GRMHD Simulations and Radiative Transfer/Particle Calculations

Abstract

Very high energy (VHE) emission has been detected from the radio galaxy NGC1275, establishing it as a potential cosmic-ray (CR) accelerator and a high energy neutrino source. We here study neutrino and $\gamma$-ray emission from the core of NGC1275 simulating the interactions of CRs assumed to be accelerated by magnetic reconnection, with the accreting plasma environment. To do this, we combine (i) numerical general relativistic (GR) magneto-hydrodynamics (MHD), (ii) Monte Carlo GR leptonic radiative transfer and, (iii) Monte Carlo interaction of CRs. A leptonic emission model that reproduces the SED in the [$10^3$-$10^{10.5}$] eV energy range is used as the background target for photo-pion interactions+electromagnetic cascading. CRs injected with the power-law index \k{appa}=1.3 produce an emission profile that matches the VHE tail of NGC1275. The associated neutrino flux, below the IceCube limits, peaks at $\sim$PeV energies. However, coming from a single source, this neutrino flux may be an over-estimation.