The study shows that the Milky Way reflects more gamma rays due to the annihilation of dark matter.

New research shows that dark matter has a different distribution in our galaxy than previously thought, and it furthers the status of dark matter as a possible source of gamma-ray excess in the center of the Milky Way. High-resolution simulations show that the distribution of dark matter in the inner galaxy is not spherical, but rather flat and asymmetric. These results confirm the theory that the gamma-ray excess is due to the collapse of dark matter.

Scientists have long ruled out the annihilation of dark matter to be the source of these rays, but the local propagation of the rays predicted this. Another theory argues that ancient millisecond pulsars could have produced the rays.

For new research published in Physical review lettersthe researchers modeled the formation of Milky Way-like galaxies under atmospheric conditions similar to Earth’s cosmic neighborhood, reproducing such newly created Milky Way-like galaxies that bear a strong resemblance to the original object.

They found that dark matter does not grow outward from the galactic center but is instead organized like stars, meaning that the former could produce as many gamma rays as they did.

“When the Fermi space telescope was pointed at the galactic center, the results were surprising. The telescope measured an abundance of gamma rays, the most powerful light in the universe. Astronomers around the world were baffled, and competing theories began to compete to explain the so-called ‘gamma-ray excess,'” (AIP).

After much debate, two ideas emerged: either these gamma rays were the result of millisecond pulsars (ultra-dense neutron stars spinning at thousands of seconds per second) or of dark matter particles breaking up and annihilating each other. Both theories have their drawbacks. However, new findings presented by scientists at AIP, a collaboration with the Hebrew University in Israel and Johns Hopkins University in the US, have shed new light on the issue, effectively confirming the theory that the gamma-ray excess is due to the depletion of dark matter.

The Milky Way galaxy has long resided in a so-called dark matter halo, a spherical region filled with dark matter surrounding it. However, this halo is not defined as spherical or elliptical in shape.

“We analyzed simulations of the Milky Way and its dark matter halo and found that the region’s flat gamma-ray excess is sufficient to explain the self-assembly of dark matter particles,” says Mortis Moro, lead author of the paper. “These calculations should be encouraged to understand.”