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Astron. Astrophys. 345, 653-662 (1999)

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Particle-acceleration and radiation in the turbulent flow of a jet

K. Manolakou 1, A. Anastasiadis 2 and L. Vlahos 1

1 Section of Astrophysics, Astronomy and Mechanics, Department of Physics, University of Thessaloniki, GR-540 06 Thessaloniki, Greece (manolaku; vlahos@astro.auth.gr)
2 Institute of Ionoshperic and Space Research, National Observatory of Athens, Palea Penteli GR-152 36, Greece (anastasi@creator.space.noa.gr)

Received 24 September 1998 / Accepted 1 February 1999


We present a numerical model for electron acceleration and radiation inside the body of an extragalactic jet. We model the jet environment as a turbulent medium generating non-linear structures (eddies and/or shocks) through a cascading process. These structures act like in-situ accelerators for the electrons that are initially injected from the central engine. Two types of acceleration processes are considered: second order Fermi-acceleration and shock-drift acceleration, depending on the velocity of the turbulent eddies encountered.

We study the modulation of the energy distribution of electrons in such an environment, by incorporating synchrotron radiation losses in the time intervals between successive interactions of the particles with the turbulent structures. By performing a parametric study with respect to the level of turbulent activity and the time intervals between interactions, we calculate the temporal evolution of the cut-off frequency of the synchrotron radiation spectrum of the particles and discuss our results in connection with recent observations.

Key words: acceleration of particles – radiation mechanisms: non-thermal – shock waves – turbulence – galaxies: jets – radio continuum: galaxies

Send offprint requests to: L.Vlahos

© European Southern Observatory (ESO) 1999

Online publication: April 19, 1999