Detection of metagalactic and galactic sources of very high-energy gamma-quanta and neutrinos with the mirror Cherenkov telescope SHALON

Abstract

Gamma-astronomy and neutrino astronomy are unique experimental possibilities to search for sources of high-energy cosmic rays ( 10 12 – 10 14 eV ) . Experimental data on sources of γ -quanta with the energy > 1 TeV are characterized by the fact that observed metagalactic sources (active galactic nuclei), being different in power from galactic sources by the factor of 10 6 – 10 7 , do not differ in the energy spectrum, F ( > E γ ) ∝ E γ - 1.3 ± 0.15 . The power of the metagalactic sources and their unlimited number casts doubts on the assumption of a galactic origin of the observed cosmic-ray flux. It is possible to assume that the uniform cosmic-ray spectrum is formed by “braking” in multiple elastic or inelastic collisions with relict photons in intergalactic space. Thus, the observed distribution of protons and cosmic-ray nuclei with the spectral index 2.72 ± 0.02 ( = 2.718 … , the Napier's constant) may be a consequence of such a “braking” that warms up the relict photons. Problems in observation of extensive air showers generated by neutrinos are connected with an extremely small cross section of inelastic collisions of neutrinos with nuclei. However, two facts allow to search for showers generated by neutrinos: (1) a hadron cascade with the primary energy of more than 10 12 eV leaves a mountain ridge to the atmosphere from the depth ∼ 300 g / cm 2 without an essential loss of the total energy in the hadron cascade, and (2) air Cherenkov radiation from such hadron cascades will be observed with a 7.5 km distant telescope over an area of more than 7 × 10 5 m 2 . This partially compensates the small cross section of inelastic neutrino collisions.