A group of Danish researchers has captured for the first time a strange kind of radiation that appears to be the center of our galaxy, which is a kind of fog around . They have concluded that this radiation emanates directly from dark matter . If they are right, the first test would be “physical” we have of their existence. The study, which will appear soon in the journal Astronomy and Astrophysics , available on ArXiv .
The Universe contains an enormous amount of dark matter , unseen for any of our instruments. We only know of its existence by the gravitational action exerted on the subject ‘normal’, which we can see and which are made all the galaxies, stars and planets. It has been estimated that, while ordinary matter accounts for only 4% of the mass of the universe , dark matter is six times more, 23% of the total. It is believed that the remaining 73% is made up of an even more mysterious ” dark energy “, which many consider responsible for the universe is accelerating its expansion .
We know that this mysterious substance that fills the voids between galaxies and, within them, the space between the stars. Since its existence was postulated , for over seventy years, several generations of scientists have tried to detect even catch some of the particles that is supposed to be formed. But everything has been futile. Now, thanks to the work of a group of researchers from the Niels Bohr Institute , University of Copenhagen Denmark, science is closer than ever to achieving this ambitious goal. Using the European Planck satellite , researchers have been detected for the first time, a strange radiation flux from the core of the Milky Way, our galaxy. And they are convinced that this radiation emanates directly from dark matter.
Launched in 2009, the Planck satellite is an extremely sensitive and able to map the entire sky visible in the range of microwave radiation . After months of work, the researchers were able to characterize in detail the unusual radiation, and also found that it is a mysterious fog that completely surrounds the galactic center . Something that, according to them, no matter may come from “normal”, which is all the stars and galaxies we can see. “Radiation-Naselsky Pavel explains, Niels Bohr Institute, can not be explained from the structural arrangements of the galaxy, and can not come from the supernova explosion. We think there could be a direct proof of the existence of dark matter . Furthermore, we have discovered a completely new and unknown mechanism for physics to explain the acceleration of particles in the center of the galaxy ” .
The first evidence of this “galactic fog” was glimpsed in 2004 by NASA’s WMAP (Wilkinson Microwave Anisotropy Probe), but since then many researchers have tried to explain it without success. In the new study, scientists at the Niels Bohr Institute used data previously collected by the WMAP and Planck himself to study the haze in the microwave range. And found that has much in common with synchrotron radiation , which is produced when electrons and positrons (the positron is the antiparticle of the electron, its “mirror” of antimatter) shoot out at relativistic speeds (an appreciable fraction of the speed of light ) through the magnetic fields from the center of our galaxy .
If the interpretation is correct, the fog could be a direct manifestation of the dark matter , whose presence seems to be denser precisely at the center of galaxies. One of the most accepted theories about dark matter says it is made of WIMPs (weakly interacting massive particles), a strange and unknown family of particles that would, in turn, matter and antimatter . When two WIMPs meet, they annihilate each other, the same thing happens when ordinary particle meets its antiparticle (made of antimatter). “The theory tells us that the concentration of dark matter particles around galactic centers is very high, ‘”says Naselsky-” and we have very strong arguments to believe that in such circumstances many collisions occur, and that as a result of these collisions form electrons and positrons . ”
According to the scientist, “these electrons and positrons then begin to rotate around the center of the magnetic field of the galaxy and in doing so produce synchrotron radiation very unusual.” This means that researchers may have witnessed the microwave radiation that is released as a result of the annihilation of dark matter particles . The finding seems to be confirmed, too, with recent data from observations carried out with the Fermi Gamma-ray Telescope and found a huge “bubble” of gamma light emanating from the center of the Milky Way. A glow that also could be due to dark matter annihilation.