Hooper and his colleagues conclude that annihilations of dark matter particles with a mass between 31 and 40 GeV provide a remarkable fit for the excess based on its gamma-ray spectrum
, its symmetry around the galactic center, and its overall brightness.
There he worked with Dr Alice Harding, and they were the first to develop a relatively accurate procedure to predict the high-energy to very high-energy gamma-ray spectrum
of the Crab Nebula.
Because a gamma-ray spectrum
reveals how much of this high-energy radiation is absorbed, it provides a tally of the lower-energy photons generated by all the galaxies that lie between the distant blazar and Earth, says Romani.
Other observers found additional light echoes (135: 155; 136; 12) and unusual characteristics in the supernova's gamma-ray spectrum
Furthermore, because the gamma-rays should be coming from a narrow shell of gas, the range of wavelengths would be small, producing a sharp line in the gamma-ray spectrum
The distinctive signature of a superdeformed state is a strikingly regular gamma-ray spectrum
-- the nucleus sequentially casts off 19 gamma rays, each of which carries two units of spin, thereby slowing down the dysprosium rotation step by step from 60 * to about 22 *.