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

TL;DR

DAMPE's 102-month gamma-ray data confirms the Fermi bubbles and Galactic center excess with high significance, supporting dark matter annihilation as a possible explanation.

Contribution

First independent detection of Fermi bubbles and Galactic center excess using DAMPE data, consistent with Fermi-LAT observations and dark matter models.

Findings

Fermi bubbles detected at ~26σ significance

Galactic center GeV excess identified at ~7σ confidence

Results support dark matter annihilation hypothesis with ~50 GeV mass

Abstract

The DArk Matter Particle Explorer (DAMPE) is a space-borne high-energy particle detector that surveys the $\gamma$-ray sky above$\sim 2~\rm GeV$ with a peak acceptance of $\sim 0.2~\rm m^2\,sr$. With the 102 months of data collected by DAMPE, we show that the Fermi bubbles are detected at a significance of $\sim 26\sigma$ and identify a GeV excess in the direction of Galactic center at $\sim 7 \sigma$ 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 $\sim 10^{-26}~{\rm cm^{3}~s^{-1}}$ for the $\chi \chi \rightarrow b\bar{b}$ channel. Our results thus provide the first independent detection of these two intriguing diffuse gamma-ray sources besides Fermi-LAT.