相关论文: The influence of collimation on the appearance of …

We reinvestigate the problem of the appearance of relativistic jets when geometrical opening is taken into account. We propose a new criterion to define apparent velocities and Doppler factors, which we think being determined by the…

Radio maps of AGNs often show linear features, called jets, both on pc as well as kpc scales. These jets supposedly possess relativistic motion and are oriented close to the line of sight of the observer and accordingly the relativistic…

The group velocity of light in material around the AGN jet is acquiescently one (c as a unit), but this is only a hypothesis. Here, we re-derive apparent superluminal and Doppler formulas for the general case (it is assumed that the group…

Thanks to the availability of high-resolution high-sensitivity telescopes such as the Very Large Array, the Hubble Space Telescope, and the Chandra X-ray Observatory, there is now a wealth of observational data on relativistic jets from…

The relationship between observed variability time and emission region geometry is explored for the case of emission by relativistic jets. The approximate formula for the jet-frame size of the emission region, $R'=Dc\Delta t_{\rm obs}$ is…

We consider radiation of relativistic electrons accelerated within the jet extended boundary layer. Due to velocity shear across the boundary the observed jet/counterjet brightness ratio is diminished as compared to the one derived for the…

The properties of wave-like helically twisted normal mode structures on steady relativistic jets are summarized. Wave speeds are a function of the wavelength and less than the jet speed. However, normal mode interference can lead to both…

We present a new, semi-analytic formalism to model the acceleration and collimation of relativistic jets in a gravitational potential. The gravitational energy density includes the kinetic, thermal, and electromagnetic mass contributions.…

The intrinsic luminosity functions of extremely fast jets found in many active galaxies and gamma-ray bursts are difficult to measure since their apparent luminosities are strongly affected by relativistic beaming. Past studies have only…

The structure of a relativistically hot, strongly magnetized jet is investigated at large distances from the source. Asymptotic equations are derived describing collimation and acceleration of the externally confined jet. Conditions are…

The amplitude of jet distortions and accompanying pressure and velocity fluctuations resulting from Kelvin-Helmholtz instability of three dimensional relativistic jets are explored. The effect of instability on jets as they accelerate from…

We had earlier shown that for a constant velocity jet the discrepancy between the low speeds indicated by VLBI knot motions and the high Doppler factors inferred from emission of TeV photons could be reconciled if ultrarelativistic jets…

We present a new, approximate method for modelling the acceleration and collimation of relativistic jets in the presence of gravity. This method is self-similar throughout the computational domain where gravitational effects are negligible…

We discuss results from a decade long program to study the fine-scale structure and the kinematics of relativistic AGN jets with the aim of better understanding the acceleration and collimation of the relativistic plasma forming AGN jets.…

AGNs jets are known to display relativistic motion on parsec scales but the accelerating mechanism as well as the exact bulk Lorentz factor of the flow are still a matter of discussion. Under certain assumptions, a plasma can be accelerated…

Collimated outflows (jets) appear to be a ubiquitous phenomenon associated with the accretion of material onto a compact object. Despite this ubiquity, many fundamental physics aspects of jets are still poorly understood and constrained.…

Supermassive black holes launch highly relativistic jets with velocities reaching Lorentz factors as high as $\Gamma>50$. How the jets accelerate to such high velocities and where along the jet do they reach terminal velocity are open…

Relativistic jets in Galactic superluminals and extragalactic AGN may be surrounded by a wind near to the central engine. Theoretical analysis and numerical simulation reveal considerable stabilization of relativistic jet flow by a wind to…

Galactic and extragalactic relativistic jets have rich environments that are full of moving objects, such as stars and dense clumps. These objects can enter into the jets and generate shocks and non-thermal emission. We characterize the…

We report a change in the trajectory of a well studied jet component of the quasar 3C279. The component changes in apparent projected speed and direction, and we find it to be moving with a Lorentz factor gamma >~ 15 at an initial angle of…