PROCEEDINGS OF THE YEREVAN STATE UNIVERSITY Physical and Mathematical Sciences 2012, No 2, p. 62–66 Physics ON THE ORIGIN OF HIGH ENERGY γ-RAYS FROM GIANT RADIO LOBES OF CENTAURUS A

Recently the Fermi LAT collaboration reported on the detection of high energy γ-ray signal from giant lobes of the radio galaxy Centaurus A. It is shown that if the γ-rays had originated from the inverse-Compton scattering of cosmic microwave background photons for the equipartition magnetic field of 2 μG, the Fermi LAT would not detect γ-rays from the lobes of Centaurus A. However, the detected γ-rays may be produced in hadronic interactions, namely in interactions of high energy protons with low density plasma followed with the production of pions, the neutral component decaying into 2γ-quanta. In this article we study the hadronic origin of γ-rays, and estimate the total energy of protons assuming a power-law proton distribution with an exponential cut-off.