Supernova remnants (SNRs) are the best candidates for galactic cosmic ray acceleration to relativistic energies via diffusive shock acceleration. The gamma-ray emission of SNRs can provide direct evidence of leptonic (inverse Compton and bremsstrahlung) and hadronic (proton-proton interaction and subsequently pion decay) processes. Puppis A is a ~ 4 kyr old SNR interacting with interstellar clouds which has been observed in a broad energy band, from radio to gamma-ray. We performed a morphological and spectral analysis of 14 years of observations with Fermi-LAT telescope in order to study its gamma-ray emission. We found a clear asymmetry in high-energy brightness between the eastern and western sides of the remnant, reminiscent to that observed in the X-ray emission. The eastern side, interacting with a molecular cloud, shows a spectrum which can be reproduced by a pion decay model. Moreover, we analyzed two gamma-ray sources located close to the remnant. The hardness of their spectra suggests that the gamma-ray emission can be due to particles escaping from the shock of Puppis A.
@article{arxiv.2308.14848,
title = {Evidence for proton acceleration and escape from the Puppis A SNR using Fermi-LAT observations},
author = {Roberta Giuffrida and Marianne Lemoine-Goumard and Marco Miceli and Stefano Gabici and Yasuo Fukui and Hidetoshi Sano},
journal= {arXiv preprint arXiv:2308.14848},
year = {2023}
}
Comments
Presented at the 38th International Cosmic Ray Conference (ICRC 2023), 8 pages, 2 figures, 3 tables