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Gamma-rays tighten window on dark matter theories

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This figure shows the observed data fitting the dark matter component, after subtracting all other components toward the Galactic Center.

02/27/2014
UC Irvine researchers reveal more data from NASA’s Fermi Gamma-ray Telescope
Tatiana Arizaga
School of Physical Sciences Communications

UC Irvine astrophysicists report that gamma-ray photons observed from the center of the Milky Way Galaxy are consistent with the intriguing possibility of dark matter annihilation, according to research submitted to the journal Physical Review D.

Kevork Abazajian, Nicolas Canac, Shunsaku Horiuchi and Manoj Kaplinghat analyzed data from NASA’s space-borne Fermi Gamma-ray Space Telescope and found that only a narrow range of dark matter models can produce an excess of gamma rays coming from the Milky Way. These gamma rays could be produced as particles of dark matter annihilate one another. The data was collected August 2008 – May 2013. The findings were also presented today at UCLA’s the 11th Symposium on Sources and Detection of Dark Matter and Dark Energy in the Universe.

“The data provides a better-than 10 percent precise determination of the dark matter’s particle mass with the best estimates we have of what else is going on in the Galactic Center,” says Abazajian.

According to Kaplinghat, the signal is robust because its key features did not change even when several other possible sources were included. He also pointed out that a large number of yet unseen pulsars emitting gamma rays could also be an explanation for this signal.

The nature of 85 percent of the matter in the universe is an unknown material called dark matter. The leading theory is that dark matter consists of weakly interacting massive particles (WIMP’s).  When two WIMP particles meet, they annihilate each other to produce more familiar particles – including gamma rays.