Interpreting correlated observations of cosmic rays and gamma-rays from Centaurus A with a proton blazar inspired model

TL;DR

This paper uses a proton blazar inspired model to explain the gamma-ray spectrum and ultra-high-energy cosmic rays observed from Centaurus A, linking electromagnetic and cosmic ray data.

Contribution

It applies a proton blazar inspired model to simultaneously explain gamma-ray spectral features and cosmic ray observations from Centaurus A.

Findings

Model explains gamma-ray spectrum hardening above a few GeV.

Model accounts for observed ultra-high-energy cosmic rays from Cen A.

Consistent explanation of electromagnetic and cosmic ray data.

Abstract

The nearest active radio galaxy Centaurus (Cen) A is a gamma-ray emitter in GeV to TeV energy scale. The High Energy Stereoscopic System (H.E.S.S.) and non-simultaneous Fermi-LAT observation indicate an unusual spectral hardening above few GeV energies in the gamma-ray spectrum of Cen A. Very recently the H.E.S.S. observatory resolved the kilo parsec (kpc)-scale jets in Centaurus A at TeV energies. On the other hand, the Pierre Auger Observatory (PAO) detects a few ultra high energy cosmic ray (UHECR) events from Cen-A. The proton blazar inspired model, which considers acceleration of both electrons and hadronic cosmic rays in AGN jet, can explain the observed coincident high energy neutrinos and gamma rays from Ice-cube detected AGN jets. Here we have employed the proton blazar inspired model to explain the observed GeV to TeV gamma-ray spectrum features including the spectrum hardening at GeV energies along with the PAO observation on cosmic rays from Cen-A. Our findings suggest that the model can explain consistently the observed electromagnetic spectrum in combination with the appropriate number of UHECRs from Cen A.