Probing the origin of 4FGL J0822.8-4207: cosmic ray illumination from the SNR Puppis A and the Herbig-Haro object HH219

TL;DR

This study investigates the origin of the gamma-ray source 4FGL J0822.8-4207, exploring cosmic ray interactions from the SNR Puppis A and the Herbig-Haro object HH219, revealing potential particle acceleration up to TeV energies.

Contribution

It presents the first detailed analysis of gamma-ray emission origin from either SNR Puppis A or HH219, proposing new scenarios for cosmic ray acceleration and interaction.

Findings

Gamma-ray emission could originate from Puppis A if gas is within 40 pc, considering diffusion and age constraints.

HH219 may accelerate particles to several TeV, producing gamma rays up to hundreds of GeV without cutoff.

The study suggests HH219 as a novel gamma-ray source, offering insights into particle acceleration in protostellar jets.

Abstract

4FGL J0822.8-4207 is a point source found in the 4FGL-DR2 catalog by the gamma-ray observatory Fermi-LAT and has no known association. We carry out X-ray observations of 4FGL J0822.8-4207 to help understand its nature. We explore two scenarios for the origin of 4FGL J0822.8-4207. In the first case we study the possibility that cosmic rays from the supernova remnant (SNR) Puppis A, seen nearby in the sky, reach the dense gas at the location of the source and produce the gamma-rays through inelastic proton-proton collisions. We apply a standard model for particle diffusion in the interstellar medium and derive the required physical parameters. We find that this scenario for the gamma rays is possible if the gas is located at a distance that is not higher than ~40 pc from Puppis A, unless the SNR is older than 7 kyr or the diffusion coefficient is higher than typical Galactic values, and relatively low-energy cosmic rays are currently escaping from the SNR. In the second scenario, we consider the protostellar jet HH219 as the origin of the GeV source and find the very interesting possibility that particles could be accelerated up to energies of at least several TeV in HH219. This would make this system the first known of its kind to produce gamma-ray emission extending up to hundreds of GeV without any apparent cutoff and an excellent laboratory to study the process of particle acceleration.