Magnetic reconnection and the origin of gamma-ray and neutrino emission in the BH accretion flow of radio-galaxies and Sagittarius A*

Data: 
10/10/2018 - 14:00 - 15:00
Local: 
Auditório "Prof. Dr. Paulo Benevides Soares", Bloco G

Magnetic reconnection and the origin of gamma-ray and neutrino emission in the BH accretion flow of radio-galaxies and Sagittarius A*

 

Juan Carlos Rodriguez

IAG/USP

 

The origin of the very high energy (VHE) emission (>100 GeV) in non-blazar sources like radio galaxies, is still a mystery. Their spectral energy distribution cannot be explained with one-zone synchrotron/self-Compton electronic emission, and their gamma-ray fluxes suggest the presence of another emission component that could be of hadronic (ion) origin. Recent multi-messenger detections of gamma-rays and neutrinos associated with the TXS 0506+056 blazar favour hadronic emission scenarios. However, these observations are difficult to interpret, as the production of neutrinos in jet environments is not efficient enough. In this talk, we discuss a scenario where cosmic-rays are accelerated in the black hole (BH) accretion flows by magnetic reconnection and then we model the gamma-ray and neutrino emission resulting from the hadronic interactions of these cosmic-rays with the local photon, matter, and magnetic fields. For this aim, we have performed general-relativistic magnetohydrodynamical simulations, leptonic radiative transfer calculations, and Monte Carlo simulations of cosmic-ray propagation in the accretion flow to obtain the resulting gamma-ray and neutrino emission. We discuss the results of our method applied to the core of Centaurus A, the nearest radio galaxy discovered as VHE gamma-ray source, and to Sagittarius A*, the BH at the centre of our galaxy and associated with a source of VHE emission.