Extragalactic MeV γ-ray emission from cocoons of young radio galaxies |
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Authors: | M Kino N Kawakatu H Ito |
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Institution: | Department of Earth and Space Science, Osaka University, 560-0043 Toyonaka, Japan;National Astronomical Observatory of Japan, 181-8588 Mitaka, Japan;Department of Science &Engineering, Waseda University, Tokyo 169-8555, Japan |
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Abstract: | Strong γ-ray emission from cocoons of young radio galaxies is predicted for the first time. Considering the process of adiabatic injection of the shock dissipation energy and mass of the relativistic jet in active nuclei into the cocoon, while assuming thermalizing electron plasma interactions, we find that the thermal electron temperature of the cocoon is typically predicted to be of the order of ~ MeV, and is determined only by the bulk Lorentz factor of the relativistic jet. Together with the time-dependent dynamics of the cocoon expansion, we find that young cocoons can yield thermal bremsstrahlung emissions at energies ~MeV. |
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Keywords: | galaxies: active galaxies: jets gamma-rays: theory |
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