On possible 'cosmic ray cocoons' of relativistic jets |
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Authors: | Micha Ostrowski |
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Institution: | Obserwatorium Astronomiczne, Uniwersytet Jagielloński, ul. Orla 171, 30-244 Kraków, Poland |
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Abstract: | We consider effects on an (ultra)relativistic jet and its ambient medium caused by high-energy cosmic rays accelerated at the jet side boundary. As illustrated by simple models, during the acceleration process a flat cosmic ray distribution can be created, with gyro-radii for the highest particle energies reaching scales comparable to the jet radius or energy density comparable to the pressure of the ambient medium . In the case of efficient radiative losses, a high-energy bump in the spectrum can dominate the cosmic ray pressure. In extreme cases, the cosmic rays are able to push the ambient medium off, providing a 'cosmic ray cocoon' separating the jet from the surrounding medium. The considered cosmic rays provide an additional jet braking force and lead to a number of consequences for the jet structure and its radiative output. In particular, the dynamic and acceleration time-scales involved are in the range observed in variable active galactic nuclei. |
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Keywords: | acceleration of particles instabilities cosmic rays galaxies: jets quasars: general |
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