Astrophys. J. 710, 236–247 (2010)

A surplus of high-energy electrons reported by instruments such as NASA's Fermi Gamma-ray Space Telescope has been interpreted as an indirect signal of dark matter, which is thought to make up around 85% of the Universe's matter. But starlight is enough to cause this excess of electrons, say Łukasz Stawarz and his colleagues at Stanford University in California.

They developed a model of electron propagation through the galaxy that they say more rigorously accounts for the effect of starlight on the electrons. By selectively scattering electrons of specific energies, starlight suppresses most electron energies in a way that gives the impression that there is an excess of certain high-energy electrons.

The model casts doubt on theories suggesting that reported instrument results indicate signs of dark matter.