Observations of the Fermi bubbles and the Galactic center excess with the DArk Matter Particle Explorer

Abstract: The DArk Matter Particle Explorer (DAMPE) is a space-borne high-energy particle detector that surveys the $γ$-ray sky above$\sim 2~\rm GeV$ with a peak acceptance of $\sim 0.2~\rm m<sup>2\,sr$. With the 102 months of data collected by DAMPE, we show that the Fermi bubbles are detected at a significance of $\sim 26σ$ and identify a GeV excess in the direction of Galactic center at $\sim 7 σ$ confidence. Both spectra and morphology are consistent with those observed by Fermi-LAT and the GeV excess component can be interpreted by the dark matter annihilation with a mass of $\sim 50$ GeV and a velocity-averaged cross section of $$\sim 10^{-26}~{\rm cm<sup>{3}~s<sup>{-1}}$$ for the $χχ\rightarrow b\bar{b}$ channel. Our results thus provide the first independent detection of these two intriguing diffuse gamma-ray sources besides Fermi-LAT.