Is the Fermi gamma-ray excess evidence for dark matter or due to milli-second pulsars?

Fermi Satellite, 3d model.
Image Source: NASA
The Large Area Telescope on board the Fermi spacecraft looks out for the most extreme events in the cosmos. Launched 2008, it scans the whole sky for gamma rays in the very high energy range, from 20 MeV to about 300 GeV; a full scan takes about 3 hours. One of Fermi�s most interesting findings is an unexpectedly large amount of gamma-rays,