Nearby dark matter subhalo that accounts for the DAMPE excess * * Supported by the foundation of Tianjin Normal University (52XB1912), the National Key R&D Program of China (2016YFA0400200) and the National Natural Science Foundation of China (U1738209, 11851303)

Abstract

The precise spectrum of electrons and positrons at high energies plays an important role in understanding their origin. DArk Matter Particle Explorer has reported their first measurement of the spectrum from 25 GeV to 4.6 TeV. This spectrum reveals a tentative peak at ~1.4 TeV, which requires a nearby source of . In this work, we study the properties of a large nearby dark matter subhalo that accouns for this spectral peak, such as its mass and distance from Earth, for different concentration models. We compare spectra of the sources in 3FGL with that from DM annihilation in the subhalo, and find ten candidates that have comparable gamma-ray spectra. However, according to the N-body simulation, the probability that such a large subhalo is close enough to Earth is less than 0.1%.