Volume 414, Number 2, February I 2004
|Page(s)||463 - 474|
|Published online||19 January 2004|
Conversion of bulk kinetic energy into radiation in AGNs and GRBs: Particle transport effects*
Space Research Laboratory (Part of Väisälä Institute for Space Physics and Astronomy, University of Turku.) , Department of Physics, 20014 University of Turku, Finland
2 Theoretical Physics Division, Department of Physical Sciences, PO Box 64, 00014 University of Helsinki, Finland
3 Institut für Theoretische Physik, Lehrstuhl IV: Weltraum- und Astrophysik, Ruhr-Universität Bochum, 44780 Bochum, Germany
Corresponding author: R. Vainio, firstname.lastname@example.org
Accepted: 9 October 2003
We investigate the spatial structure of collisionless collision fronts in relativistic outflows interacting with ambient material. As a result of the interaction, ambient particles are picked up by the outflow and generate transverse plasma waves via streaming instabilities. Pick-up particle transport under the influence of self-generated turbulence inside such interaction regions is studied. We extend our previous momentum space modeling to include also a spatial dimension. We find that the following possibilities are consistent with quasi-linear equations of particle transport and wave generation: (i) if background waves have small intensities inside the outflow region, leading to inefficient scattering across the pitch-angle, θ, of , particles are isotropized in the backward hemisphere (relative to the outflow velocity vector) and self-generated waves have a steep, wavenumber spectrum; (ii) if background waves have large intensities, enabling particles to cross , particles can be fully isotropized. In case (i), however, the calculated self-generated wave amplitudes are close to the magnitude of the ordered field for reasonable choices of model parameters, giving the particles a chance to be scattered across the resonance gap by non-resonant processes. If the resonance gap is filled, a large fraction of the pick-up particles is expected to return to the upstream region, and an ultra-relativistic shock wave is predicted to form in front of the outflow, where the two relativistic particle populations (ambient and reflected) mix and form a relativistic plasma. Reflection of pick-up protons decreases the -decay luminosity of relativistic outflows, leading to a need to update parameters of previous modeling. An example of outflow parameters reproducing typical TeV-blazar observations is presented.
Key words: instabilities / turbulence / galaxies: BL Lacertae Objects: general / gamma rays: theory / shock waves
© ESO, 2004
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.