We investigate the possibility that gamma-ray bursts are powered by a central engine
consisting of a black hole with an external magnetic field anchored in a surrounding disk or …

Long-duration gamma-ray bursts (GRBs) require an engine capable of driving a jet of
plasma to ultrarelativistic bulk Lorentz factors of up to several hundred and into narrow …

Accretion flows, winds and jets of compact astrophysical objects and stars are generally
described within the framework of hydrodynamical and magnetohydrodynamical (MHD) …

In relativistic, Poynting-dominated outflows, acceleration and collimation are intimately
connected. An important point is that the Lorentz force is nearly compensated by the electric …

Unconfined relativistic outflows from rotating, magnetized compact objects are often well
modeled by assuming that the field geometry is approximately a split-monopole at large …

Periodicities in blazar light curves may be related to helical trajectories in extragalactic radio
jets by differential Doppler boosting effects. We consider ballistic and nonballistic (ie, radial) …

The goal of this paper is to derive signatures of synchrotron radiation from state-of-the-art
simulation models of collimating relativistic magnetohydrodynamic (MHD) jets featuring a …

We consider the acceleration of energetic particles by a velocity shear in the relativistic
background flow containing scattering centers. Three possible acceleration sites for …

We consider a stationary axisymmetric force-free degenerate magnetosphere of a rotating
Kerr black hole surrounded by a thin, Keplerian, infinitely conducting accretion disk. We …

Context. The observation of rapidly variable very high energy (VHE) gamma-rays from non-
aligned active galactic nuclei (AGNs), as reported from M 87, proves challenging for …