New research shows that dark matter has a different distribution in our galaxy than previously thought, and that advances dark matter’s status as a potential source of the observed gamma ray excess in the Milky Way’s center.
High-resolution simulations reveal that the dark matter distribution in the inner galaxy is not spherical, but flattened and asymmetrical.
The findings confirm the theory that the gamma ray excess is due to dark matter annihilation.
Scientists have long suspected dark matter annihilation to be a source of these rays, but the rays’ spatial spread did not match the arrangement of dark matter they had predicted.
The Milky Way galaxy has long been known to live in a so-called dark matter halo, a spherical region filled with dark matter around it.
Dark matter’s position as a possible cause of the observed gamma ray excess in the Milky Way’s center is advanced by new research that reveals that dark matter is distributed differently in our galaxy than previously believed. According to high-resolution simulations, the inner galaxy’s dark matter distribution is asymmetrical and flattened rather than spherical. According to the results, dark matter annihilation is the cause of the excess gamma rays.
Although dark matter annihilation has long been suspected by scientists as the source of these rays, the rays’ spatial distribution did not match their predicted dark matter arrangement. According to another theory, the rays might have been produced by old millisecond pulsars.
In order to create simulated Milky Way-like galaxies that closely resemble the real thing, scientists modeled how these galaxies would form in environments similar to those found in Earth’s cosmic neighborhood. The results of this study were published in Physical Review Letters.
They discovered that rather than radiating outward from the Galactic Center, dark matter is arranged similarly to stars, which means that the former could have produced the excess gamma rays just as equally.
“The findings were shocking when the FERMI space telescope pointed toward the galactic center. The most energetic type of light in the universe, gamma rays, were measured by the telescope in excess. The so-called ‘gamma ray excess’ baffled astronomers worldwide, and competing theories began to emerge to explain it, according to Noam Libeskind of the Leibniz Institute for Astrophysics Potsdam (AIP).
The two main theories that emerged after much discussion were that these gamma rays were caused by dark matter particles crashing into one another and annihilating, or that they were the result of millisecond pulsars, which are ultra-dense neutron stars that spin thousands of times seconds. There are problems with both theories. But the new findings from AIP researchers working with Johns Hopkins University in the United States and Hebrew University in Israel. A. have provided fresh insight into this issue, essentially validating the hypothesis that dark matter annihilation is the cause of the excess gamma rays.
It has long been understood that the Milky Way galaxy is surrounded by a spherical area of dark matter known as the “dark matter halo.”. However, it has not been determined to what degree this halo is ellipsoidal or aspherical.
