相关论文: Parabolic jet shape on parsec scales in high redsh…

Physical parameters of AGN jets observed with Very Long Baseline Interferometry (VLBI) are usually inferred from the core shift measurements or flux and size measured at a peak frequency of the synchrotron spectrum. Both are preceded by…

Multi-frequency (4.6, 5, 5.5, 8, 8.8, 13, 15, 22 & 43 GHz) polarization observations of 6 "blazars" were obtained on the American Very Long Baseline Array (VLBA) over a 24-hr period on 2 July 2006. Observing at several frequencies,…

The idea that systematic Faraday Rotation gradients across the parsec-scale jets of AGNs can reveal the presence of helical magnetic (B) fields has been around since the early 1990s. These gradients are taken to be due to the systematic…

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 different methods to derive the jet velocity and orientation on the parsec scale are presented. From these methods I will discuss the velocity distribution of parsec scale jets and the possible presence of acceleration or deceleration…

We consider axisymmetric relativistic jets with a toroidal magnetic field and an ultrarelativistic equation of state, with the goal of studying the lateral structure of jets whose pressure is matched to the pressure of the medium through…

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…

The jets of active galactic nuclei can carry a large fraction of the accreted power of the black-hole system into interstellar and even extragalactic space. They radiate profusely from radio to X-ray and gamma-ray frequencies. In the most…

Radial gradients of the brightness temperatures along the parsec-scale jets of Active Galactic Nuclei (AGN) can be used to infer the energy balance and to estimate the parameter range of physical conditions in these regions. In this paper,…

In extragalactic jets, the apparent position of the bright/narrow end (the core) depends on the observing frequency, owing to synchrotron self-absorption and external absorption. The effect must be taken into account in order to achieve…

The interaction of supersonic laser-generated plasma jets with a secondary gas target was studied experimentally. The plasma parameters of the jet, and the resulting shock, were characterized using a combination of multi-frame…

In the paradigm of magnetic launching of astrophysical jets, instabilities in the MHD flow are a good candidate to convert the Poynting flux into the kinetic energy of the plasma. If the magnetised plasma fills the almost entire space, the…

We have investigated particle acceleration and emission from shocks and shear flows associated with an unmagnetized relativistic jet plasma propagating into an unmagnetized ambient plasma. Strong electro-magnetic fields are generated in the…

Context. The high-redshift (z = 4.72) blazar J1430+4204 produced a major radio outburst in 2005. Such outbursts are usually associated with the emergence of a new component in the inner radio jet. Aims. We searched for possible changes in…

We report multi-frequency VLBI studies of the sub-parsec scale structure of the two-sided jet in the nearby radio galaxy NGC 4261. Our analyses include new observations using the Source Frequency Phase Referencing technique with the Very…

The recent discovery, by the Chandra satellite, that jets of blazars are strong X-ray emitters at large scales (0.1-1 Mpc) bears support to the hypothesis that (also) on these scales the emitting plasma is moving at highly relativistic…

We present a new method to measure Gamma*theta_j in flux-limited samples of active galactic nuclei (AGN) jets, where Gamma is the bulk Lorentz factor and theta_j is the jet's half-opening angle. The Gamma*theta_j parameter is physically…

We consider the polarization properties of photospheric emission originating in jets consisting of a highly relativistic core of opening angle theta_j and Lorentz factor Gamma_0, and a surrounding shear layer where the Lorentz factor is…

Relativistic jets associated with long/soft gamma-ray bursts are formed and initially propagate in the interior of the progenitor star. Because of the subsequent loss of their external pressure support after they cross the stellar surface,…

We analyze the polarization of optically thin, stationary, axisymmetric black hole jets at scales of order the light cylinder radius. Our work generalizes the face-on results of Gelles et al. (2025) to arbitrary viewing inclination. Due to…