Dark matter origin gains support from Galactic center gamma rays

Researchers at Johns Hopkins University say they have strengthened the case that a diffuse glow of gamma rays near the center of the Milky Way may be produced by collisions of dark matter particles, a finding that, if confirmed, could represent the first direct evidence of the elusive substance. In a paper published in Physical Review Letters, the team used supercomputer simulations of the galaxy's formation to predict where dark matter should be concentrated and compared that map with gamma-ray measurements collected by NASA's Fermi Gamma-ray Space Telescope since 2008.

The study models how the Milky Way assembled from smaller dark matter and ordinary-matter systems early in its history. As ordinary matter cooled and sank toward the galactic center, the simulations show that accompanying clumps of dark matter would have migrated inward and clustered in the core, increasing the rate of dark-matter collisions. Those collisions, the researchers say, would produce a faint, diffuse gamma-ray signal that matches the excess observed by Fermi in both spatial pattern and other characteristics. "Gamma rays, and specifically the excess light we're observing at the centre of our galaxy,...