Testing Hadronic Models of Gamma Ray Production at the Core of Cen A

TL;DR

This paper investigates hadronic models for gamma ray production at Cen A's core, testing scenarios involving proton and heavy nuclei interactions to explain observed cosmic rays and gamma rays.

Contribution

It explores alternative hadronic interaction mechanisms, including $p-p$, $Fe-p$, and photo-disintegration, expanding beyond previous $p- ext{gamma}$ interaction models.

Findings

Proton-proton interactions can produce gamma rays consistent with observations.

Heavy nuclei interactions, including photo-disintegration, are viable sources of high energy gamma rays.

Different hadronic scenarios offer plausible explanations for cosmic ray and gamma ray data from Cen A.

Abstract

Pierre Auger experiment has observed a few cosmic ray events above 55 EeV from the direction of the core of Cen A. These cosmic rays might have originated from the core of Cen A. High energy gamma ray emission has been observed by HESS from the radio core and inner kpc jets of Cen A. We are testing whether pure hadronic interactions of protons or heavy nuclei with the matter in the core region or photo-disintegration of heavy nuclei can explain the cosmic ray and high energy gamma ray observations from the core of Cen A. The scenario of $p-\gamma$ interactions followed by photo-pion decay has been tested earlier by Sahu et al. (2012) and found to be consistent with the observational results. In this paper we have considered some other possibilities (i) the primary cosmic rays at the core of Cen A are protons and the high energy gamma rays are produced in $p-p$ interactions,(ii) the primary cosmic rays are Fe nuclei and the high energy gamma rays are produced in $Fe-p$ interactions and (iii) the primary cosmic rays are Fe nuclei and they are photo-disintegrated at the core. The daughter nuclei de-excite and high energy gamma rays are produced.