"X-rays of a specific wavelength emanating from the hearts of nearby galaxies and galaxy clusters could be signs of particles of dark matter decaying in space, two independent teams of astronomers report (first study, second study). If that interpretation is correct, then dark matter could consist of strange particles called sterile neutrinos that weigh about 1/100 as much as an electron."
http://science.slashdot.org/story/14/03/01/2032216/x-rays-from-other-galaxies-could-emanate-from-particles-of-dark-matter
