"We detected gamma rays with a photon energy of 20 gigaelectronvolts -- or 20 billion electronvolts, an extremely large amount of energy -- extending to a halolike structure toward the center of the Milky Way galaxy," study author Tomonori Totani said in a University of Tokyo press release.

"The gamma-ray emission component closely matches the shape expected from the dark matter halo," said Totani, professor at the university's Department of Astronomy.