Morphology of γ-ray emission induced by e± from annihilating self-interacting dark matter

作者：Cui, Ming-Yang; Zhang, Cun; Zong, Hong-Shi^*

来源：PHYSICAL REVIEW D, 2016, 93(12): 123516.

DOI：10.1103/PhysRevD.93.123516

• FERMI-LAT OBSERVATIONS
• EXCESS
• PROPAGATION
• CANDIDATES
• ENERGIES
• SIGNAL
• MILKY
• HAZE

With the Fermi-LAT data, quite a few research groups have reported a spatially extended GeV gamma-ray excess surrounding the Galactic center ( GC). The physical origin of such a GeV excess is still unclear, and one interesting possibility is the inverse Compton scattering of the electrons and positrons from annihilation of self-interacting dark matter (SIDM) particles with the interstellar optical photons. In this work, we calculate the morphology of such a gamma-ray emission. For the annihilation channel of (chi) over bar chi -> phi phi -> e(+)e(-)e(+)e(-), the inverse Compton scattering (ICS) dominates over the bremsstrahlung on producing the GeV gamma-ray emission. For the SIDM particles with a rest mass m(chi) similar to tens GeV that may be favored by the modeling of the Galactic GeV excess, the ICS radiation at GeV energies concentrates along the Galactic plane. The degrees of asymmetry high up to >= 0.3 are found in some regions of interest, which in turn proposes a plausible test on the SIDM interpretation of the GeV excess.

• 出版日期2016-6-13
• 单位南京大学; 中国科学院紫金山天文台