On the Gamma-Ray Emission of the Andromeda Galaxy M31

Abstract Using the γ -ray data obtained with Large Area Telescope on board Fermi Gamma-ray Space (Fermi) for ∼14 yr, we examine high-energy emission emanating from center of Andromeda galaxy M31. Different previously reported results, which show a seemingly extended source, instead find two individual point sources, one consistent being at and 0.°4 southeast center. The former is well described using log-parabola model, similar to those previous studies, that latter can be fitted power law. We discuss possible origins sources. M31's central now necessitates revisit its discussed originations this new property taken into consideration, in particular cosmic rays or dark matter scenarios involving source distributions. SE appears have projected distance ∼6 kpc center, investigation required as whether it locally associated M31, background extragalactic one.