by "I couldn't believe my eyes," said Esra Bulbul of the Harvard Center for Astrophysics in July of 2014. "What we found, at first glance, could not be explained by known physics." Together with a team of more than a half-dozen colleagues, Bulbul used NASA's Chandra X-Ray Observatory to explore the Perseus Cluster, a swarm of galaxies approximately 250 million light years from Earth. Imagine a cloud of gas in which each atom is a whole galaxy—that's a bit what the Perseus cluster is like. It is one of the most massive known objects in the Universe. The cluster itself is immersed in an enormous 'atmosphere' of superheated plasma—and it is there that the mystery resides.
The spectral line appears not to come from any known type of matter, which shifts suspicion to the unknown: dark matter.
"After we submitted the paper, theoreticians came up with about 60 different dark matter types which could explain this line. Some particle physicists have jokingly called this particle a 'bulbulon'," she laughed.
The menagerie of dark matter candidates that might produce this kind of line include axions, sterile neutrinos, and "moduli dark matter" that may result from the curling up of extra dimensions in string theory.
http://www.dailygalaxy.com/my_weblog/20 ... pular.html
