Gamma Rays Could Help Solve Dark Matter Mystery

Researchers have discovered a galaxy orbiting the Milky Way and emitting a surprising amount of electromagnetic radiation in the form of gamma rays.

According to researchers, the finding may be the latest in a long string of cosmic false alarms. They also hypothesized that it could be filled with annihilating dark matter particles.

"Something in the direction of this dwarf galaxy is emitting gamma rays," said Geringer-Sameth, the study's lead author. "There's no conventional reason this galaxy should be giving off gamma rays, so it's potentially a signal for dark matter."

It's believed that Dark Matter make up for 85 percent of all the mass in the known universe. However, these don't interact with normal ('bayonic') matter via the electromagnetic force, hence remain invisible and mysterious.

"In the search for dark matter, gamma rays from a dwarf galaxy have long been considered a very strong signature," Savvas Koushiappas of Brown University said in a press release. "It seems like we may now be detecting such a thing for the first time."

The discovered dwarf galaxy, named Reticulum 2, is 98,000 light-years from Earth, one of the nearest dwarf galaxies yet detected.

"There did seem to be an excess of gamma rays, above what you would expect from normal background processes, coming from the direction of this galaxy," Geringer-Sameth said. "Given the way that we think we understand how gamma rays are generated in this region of the sky, it doesn't seem that those processes can explain this signal."

Further study of this dwarf galaxy's attributes could reveal hidden sources that may be emitting gamma rays, but the researchers are cautiously optimistic, the press release noted.

The analysis was submitted to the journal Physical Review Letters.