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 ${\hat{I}}^3$-ray sky above$\sim 2\mathrm{GeV}$ with a peak acceptance of $\sim 0.2{\mathrm{m}}^2\mathrm{sr}$. With the 102 months of data collected by DAMPE, we show that the Fermi bubbles are detected at a significance of $\sim 26\ddot{I}ƒ$ and identify a GeV excess in the direction of Galactic center at $\sim 7\ddot{I}ƒ$ 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 $\sim 10^{-26}\mathrm{c}{\mathrm{m}}^3{\mathrm{s}}^{-1}$ for the $\ddot{I}‡\ddot{I}‡\to b\bar{b}$ channel. Our results thus provide the first independent detection of these two intriguing diffuse gamma-ray sources besides Fermi-LAT.

24 pages, 18 figures and 6 tables, accepted for publication in ApJS