Extragalactic gamma-ray emission produced by cosmic rays as a tool to explore active galactic nuclei

2^nd International Conference on Astrophysics and Particle Physics

November 13-15, 2017 San Antonio, USA

Anna Uryson

Lebedev Physical Institute, Russia

Posters & Accepted Abstracts: J Astrophys Aerospace Technol

Abstract :

In space, ultra-high energy cosmic rays lose energy in interaction with cosmic microwave background. This results in a lack of particles at energies about 1020 eV at the Earth (GZK-effect) if cosmic rays come from distances of more than ~ 100 Mpc. Another effect of interaction with cosmic microwave background is electromagnetic cascades that particles initiate in extragalactic space. Assuming that sources of ultra-high energy cosmic rays are active galactic nuclei (AGN) we have calculated cosmic ray energy spectra at the Earth and intensity of cascade quanta produced. We consider several varieties of AGNs including one in which supermassive black hole in AGN is surrounded by a superstrong magnetic field of 1010-1011 Gs. Comparing numerical results with spectra measured by Pierre Auger Observatory and Telescope Array and with gamma-ray intensity measured by Fermi LAT we discuss the probable fraction of AGNs surrounded by superstrong magnetic fields.