Bulletin of Taras Shevchenko National University of Kyiv. Astronomy, no. 58, p. 44-48 (2018)

TeV gamma-ray radiation from Vela supernova remnant

R. Gnatyk, ing.
K. Vynokurova, stud.

Astronomical Observatory of Taras Shevchenko National University of Kyiv, Kyiv


Sources and mechanisms of acceleration of the cosmic rays (CR) – a stream of nuclei, electrons and, to a lesser extent, antiparticles with a nonthermal power law energy spectrum extending to energies above 1020 eV, are still unknown. Theoretical calculations and experimental data show that the diffusive acceleration of the CR at the shock wave fronts (first order Fermi mechanism) in Galactic sources, first of all in the Supernova remnants (SNR), may be responsible for the observed CR flux with energies up to E ≤ 1018 eV. In this case, the lepton component of the CR (electrons, positrons) is confidently manifested in the SNR due to synchrotron radiation in a turbulent magnetic field inside the SNR. At the same time, the proton and nuclear component is not effective in synchrotron emission under typical CR parameters and magnetic fields in the SNR. Its presence in the SNR can be revealed due to the hadron mechanism of gamma-ray generation – the decay of neutral pions generated by inelastic collisions of the CR with particles-targets – atoms of interstellar medium inside and in the vicinity of SNR. Now only a few SNRs with a detectable gamma-ray flux of a hadron origin are known, in which the interaction of SNR with molecular clouds is observed, which provides the necessary concentration of particles-targets for CR. In our work we calculate the expected fluxes of such gamma-radiation from the Vela SNR, one of the closest SNR to the Earth, which evolves in a cloudy interstellar medium and is a potential candidate for the hadron mechanism gamma-ray source. The possibility of detecting Vela SNR with modern (Magic, HAWC, H.E.S.S.) and future (CTA) gamma-ray detectors is analyzed. It is shown that the sensitivity of CTA will be sufficient to detect the gamma-radiation generated by the hadron mechanism. Also we analyzed the possibility of registration of localized sources of gamma-radiation within the Vela SNR due to the presence of high gas density clouds. The fluxes from the two most massive clouds within the Vela SNR are calculated and compared with the sensitivity of the modern and future gamma-ray detectors. It is shown that sufficient sensitivity to detect the most massive clouds within the SNR will have the CTA facility if the spectrum of the gamma-rays generated by the hadron mechanism is without cut-off on the energy 10 TeV.

Key words
Cosmic rays, gamma-ray radiation, Supernova remnants, Vela Supernova remnant

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DOI: https://doi.org/10.17721/BTSNUA.2018.58.44-48