Is darkish matter accountable for further gamma rays coming from the middle of the Milky Means?

For years, astronomers have puzzled over a strange excess of gamma rays coming from the galactic center. Dark matter annihilation has always been a tempting explanation, and new research suggests that this is the best answer.

For the past 11 years, NASA’s Fermi-LAT gamma-ray telescope has observed a strange excess of high-energy radiation coming from the direction of our galactic center. The origin of the gamma rays, which are relatively diffuse around the core, does not currently have a good explanation.

While there are many possible explanations, the idea that the gamma rays can be emitted from dark matter is perhaps the most intriguing. In most models of dark matter (the mysterious, invisible form of matter that makes up over 80% of the mass of the universe), the dark matter particles can occasionally interact. When they do, they annihilate each other in a flash of gamma rays.

This interaction is very, very rare. But dark matter models predict a whole range of things in the cores of galaxies. Enough that it could light up in gamma rays.

Recently, a team of researchers refined this dark matter model and compared it to more mundane explanations, such as an additional population of cosmic rays that create the excess gamma rays.

“The analysis method used,” explains Mattia di Mauro, researcher at the Turin National Institute of Nuclear Physics and lead author of the new study, “has provided very relevant information about the spatial distribution of excess gamma radiation, which can explain what the excess of high-energy photons is generated in the galactic center.

For example, if the excess were caused by the interaction between cosmic rays and atoms, we would expect its greater spatial distribution to be observed at lower energies and its less diffusion to be observed at higher energies due to the propagation of cosmic particles. On the other hand, my study underlines how the spatial distribution of the surplus does not change as a function of energy. This aspect had never been observed before and could be explained by the interpretation of dark matter. This is because we believe that the particles that make up the dark matter halo should have similar energies. The analysis clearly shows that the excess of gamma rays is concentrated in the galactic center, exactly what we would expect in the heart of the Milky Way if dark matter were indeed a new type of particle. “

However, the result is far from conclusive. While dark matter models can be forced to explain the excess, astronomers would have to independently test this idea before accepting it.

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