Is the strange radiation in the Milky Way due to dark matter?

In 2009, physicists named Lisa Goodenough and Dan Hooper discovered a strange glow in the Milky Way – or the galaxy, if you prefer. This mysterious light is more precisely in the center of the Milky Way, explains Science Alert, and even if you subtract all the light emanating from the stars, this “gamma ray” is still consistent.

Scientists have called it the Galactic GeV Excess Center (GCE) and since its discovery they have not stopped looking for the cause of this radiation. In fact, Mattia Di Mauro, a physicist at the National Institute for Nuclear Physics in Italy, has just presented his theory on this subject. According to his research, it would be dark matter that would cause this gamma radiation, which corresponds to the hypothesis of Lisa Goodenough and Dan Hooper.

80% of the universe is made up of dark matter

Dark matter is a hypothetical category of matter that is used to account for certain astrophysical observations, e.g. B. Estimates of the mass of galaxies or the properties of fluctuations in the cosmic diffuse background. In other words, we don’t yet know exactly what dark matter is. However, scientists agree that there is a mysterious mass that still covers 80% of the universe but is not visible and that is the origin of strange gravitational effects.

For example, researchers believe that galaxies would spin faster if they weren’t influenced by dark matter, and the gravitational lens would also be more powerful than it is now. Researchers Goodenough and Hooper explained that gamma radiation could be caused by dark matter particles called massive weak interaction particles (WIMPS) that collide with antiparticles, and that their destruction causes gamma radiation. But this theory was not unanimous among physicists.

A strange glow in the Milky Way. Photo credit: (NASA Goddard; A. Mellinger, CMU; T. Linden, University of Chicago)

In 2018, other scientists argued that this excessive brightness could be due to very old dead stars called pulsars. Finally, another team of scientists put dark matter theory back on the table by stating that WIMPS could be the source of gamma rays.

Scientists are more puzzled than ever about the origin of these gamma rays

In particular, Di Mauro’s study compared data from the Fermi telescope over the past 11 years with data collected by the Pamela cosmic ray detector on board the Resurs-DK No. 1 satellite and the ISS’s Alpha Magnetic Field spectrometer astronomical Anomalies.

According to Di Mauro, this information allowed certain theories, such as the interaction between cosmic rays and atoms, to be ruled out. This researcher therefore affirmed in his study published in Physical Review D that “the analysis clearly shows that the excess of gamma rays is concentrated in the galactic center, exactly what one would expect in the heart of the Milky Way if dark matter were a new species of particles “. But at the moment we don’t know what this particle is.

In another article, Di Mauro and colleague Martin Wolfgang Winkler of Stockholm University in Sweden tried to detect this particle by looking for excess gamma rays in nearby dwarf spherical galaxies, but did not find any. Instead, they found that the mass of the dark matter particle is under tension. Restrictions that are therefore compatible with the GCE.

After all, the researchers believe that we cannot yet say that dark matter is the cause of gamma radiation, but that doesn’t mean they emphasize that it has nothing to do with that radiation. While scientists are not yet at a loss about this gamma radiation, they do not give up hope that one day they will be able to determine its cause.