An international team of astrophysicists with the participation of the National Research Nuclear University "MEPhI" discovered a signal of high-energy galactic photons in the data of the Fermi experiment. This discovery could shed light on the origin of the high-energy neutrinos previously recorded by the IceCube Neutrino Observatory at Amundsen-Scott Station in Antarctica. The discovery was reported in the journal Physical Review-D.
The neutrino travels where other particles get stuck. For example, solar neutrinos come from the interior of the sun and provide information about thermonuclear reactions in the solar core. High-energy neutrinos come to us from yet unknown extraterrestrial objects and provide information that is not available with other methods of observation.
Researchers at the National Research Nuclear University MEPhI, together with colleagues from the University of Paris-Diderot (France), the Norwegian University of Science and Technology (Norway), the University of Geneva (Switzerland), while studying the data of the Fermi gamma telescope at high energies (above 300 GeV), discovered a new component in the flux of gamma radiation.
“At energies above 300 GeV, signals from sources outside our Galaxy will be strongly suppressed due to the absorption of gamma radiation in intergalactic space. Moreover, at distances within the Galaxy, gamma radiation is practically not absorbed. Thus, the new component must have a source in our Galaxy, one of the authors of the study, professor at NRNU MEPhI, Dmitry Semikoz, told RIA Novosti.
According to the scientist, the spectrum of the new component is in good agreement with the abnormally high flux of neutrinos recently discovered in the IceCube experiment. Since neutrinos are always "produced" along with gamma rays, which have a similar spectrum, scientists have assumed that both spectra have a common origin.
“In this paper, we have proposed two models to explain all the data,” said Professor Semikoz. - In the first model, neutrinos and gamma radiation are produced in the nearby region of the Galaxy due to the interaction of cosmic rays. In the second model, neutrinos and gamma radiation emerged as a result of the decay of dark matter in our Galaxy”.
Which of these models is correct, it will be possible to establish from the signal inhomogeneity during further studies. If the source of the signal is the decay of dark matter, the importance of this study can hardly be overestimated. But even in the case of a nearby astrophysical source, we may have had a chance for the first time to find a source of cosmic rays that produce the observed neutrinos and gamma rays.
At present in Russia, at the bottom of Lake Baikal, an underwater neutrino telescope 'Gigaton Water Detector' with a volume of one cubic kilometer is being built. It is planned that in 2020 the Baikal telescope will become comparable in sensitivity to the IceCube experiment. And for observing the central part of our Galaxy, the Baikal telescope is even better suited than IceCube, since it is located in the northern hemisphere (neutrino researchers in Antarctica observe particles literally "through the Earth").
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