An international group of astrophysicists with the participation of scientists from the National Research Nuclear University MEPhI (Moscow Engineering Physics Institute) has discovered a strange signal of high-energy galactic photons in the Fermi experiment.
The discovery was reported in the journal “Physical Review-D.”
This discovery may help scientists in explaining the origin of high-energy neutrinos, which have previously been recorded using the IceCube Neutrino Observatory located at the Amundsen-Scott Antarctic station.
Neutrinos can penetrate through matter where other particles simply can’t.
Solar neutrinos, for example, come from the very depths of the Sun and offer scientific information about thermonuclear reactions that occur inside the Solar core.
High-energy neutrinos are believed to come from an unknown extraterrestrial object (or objects) and offer unprecedented data that is not available by other methods of observation.
Now, astrophysicists from the Moscow Engineering Physics Institute and colleagues from the Paris Diderot University (France), the Norwegian University of Science and Technology (Norway), the University of Geneva (Switzerland) have discovered what they believe is a new component in the gamma-ray flux when they investigated data of the Fermi gamma telescope at high energies (above 300 GeV).
They discovered an extraterrestrial signal.
“At energies above 300 GeV, signals from sources outside our Galaxy will be severely suppressed by gamma-ray absorption in intergalactic space. At the same time, gamma radiation is practically not absorbed within the Galaxy. Thus, a source of the new component should be in our Galaxy”, said one of the authors of the study, Professor at MEPhI Dmitry Semikoz.
According to the experts, the spectrum of the new component is similar to the abnormally high neutrino flux recently found by experts in the IceCube experiment.
Scientists say that as neutrinos are always “produced” together with gamma radiation, which has a similar spectrum, scholars theorize that both spectra have a common origin.
“In this research, we proposed two models that explain all the data,” said Professor Semikoz. “In the first model, neutrino and gamma radiation are produced in a close to us region of the Galaxy because of the interaction of cosmic rays. In the second model, neutrinos and gamma rays were produced by the decay of dark matter in our Galaxy.”
It will be possible to ascertain these models by the heterogeneity of the signal in further studies. If the decay of dark matter is the signal’s source, the importance of this study cannot be overestimated. But even in the case of a close astrophysical source, for the first time, we may have a chance to find the source of cosmic rays that produce the observed neutrino and gamma radiation.