Mysterious glow in space: "Dark matter self-destructs"

The mysterious gamma-rays emitted from the center of the Milky Way are called the "Galactic Center GeV Excess (GCE)" by astronomers. Discovered in 2009 in data from NASA's Fermi Gamma-ray Space Telescope, this glow is one of the highest-energy types of light in the universe, yet its source remains undetermined.

According to a new study, this gamma-ray excess can be explained by one of two possible sources:

The annihilation of dark matter particles (collisions of WIMPs) or millisecond pulsars, which are rapidly spinning neutron stars in the final stages of their lives.

The team, led by Moorits Mihkel Muru of the Leibniz Institute for Astrophysics in Germany, modeled the distribution of dark matter in the Milky Way with supercomputer simulations.

"BOXED" FORM

The findings, published in the journal Physical Review Letters, showed that our galaxy's dark matter halo may not be perfectly spherical but rather slightly flattened. This means that gamma rays from dark matter could form a "boxy" shape, much like the light from pulsars.

This result suggests that the shape of the GCE does not exclude the possibility of dark matter, and that the dark matter hypothesis may even have a slight advantage.

According to the researchers, both scenarios are still valid: Part of the GCE may be caused by millisecond pulsars, while part may be caused by dark matter interactions.

"Dark matter shapes the universe. These gamma rays could be the first real traces of it," said Joseph Silk, an astrophysicist at Johns Hopkins University.

Scientists hope that this mystery can be shed light on the upcoming Cherenkov Telescope Array and the Southern Wide Field Gamma-ray Observatory.