New H.E.S.S. diffuse emission from the Galactic center

Lacroix et al. (2016) show that the newly detected H.E.S.S. (High Energy Stereoscopic System) gamma-ray diffuse emission from the Galactic center below 0.45 deg can be accounted for by inverse Compton emission from millisecond pulsars and heavy (~ 100 TeV) dark matter annihilating to electrons or muons with a thermal or sub-thermal cross-section, provided that the dark matter density profile features a supermassive black hole-induced spike on sub-pc scales.

Image: Center of our Galaxy. Credit: NASA, ESA, SSC, CXC, and STScI

They discuss the impact of the interstellar radiation field, magnetic field and diffusion set-up on the spectral and spatial morphology of the resulting emission. For well-motivated parameters, they show that the DM-induced emission reproduces the spatial morphology of the H.E.S.S. signal above ~ 10 TeV, while they obtain a more extended component from pulsars at lower energies, which could be used as a prediction for future H.E.S.S. observations.

• Lacroix et al. 2016 (preprint) - New H.E.S.S. diffuse emission from the Galactic center: a combination of heavy dark matter and millisecond pulsars? (arXiv)