Puppis A Fermi-LAT TS and eROSITA images

We analyze 14 years of Fermi-LAT observations of the supernova remnant Puppis A to investigate its asymmetric gamma-ray morphology and spectral properties. This middle-aged remnant (~4kyr) is evolving in an inhomogeneous environment, interacting with a dense molecular cloud in the northeast and a lower-density medium in the southwest.

We find clear differences in both gamma-ray luminosity and spectral energy distribution between these two regions. The emission from both sides is consistent with a hadronic origin. However, while the southwestern emission can be explained by standard Diffusive Shock Acceleration (DSA), the northeastern side may involve re-acceleration of pre-existing cosmic rays or acceleration via reflected shocks in the dense cloud environment.