Related papers: Magnetization of jets in luminous blazars
We investigate the dependence of gamma-ray brightness of blazars on intrinsic properties of their parsec-scale radio jets and the implication for relativistic beaming. By combining apparent jet speeds derived from high-resolution VLBA…
The Fermi-LAT survey provides a large sample of blazars selected on the strength of their inverse Compton emission. We cross-correlate the first Fermi-LAT catalogue with the CRATES radio catalogue and use this sample to investigate whether…
Rapid and luminous flares of non-thermal radiation observed in blazars require an efficient mechanism of energy dissipation and particle acceleration in relativistic active galactic nuclei (AGN) jets. Particle acceleration in relativistic…
The new high energy data coming mainly from the Fermi and Swift satellites and from the ground based Cerenkov telescopes are making possible to study not only the energetics of blazar jets, but also their connection to the associated…
Black-hole driven relativistic astrophysical jets, such as blazars and gamma-ray bursts (GRBs), are powerful sources of electromagnetic radiation. Their emission is powered by some energy dissipation and particle acceleration mechanism…
High resolution radio observations remain the most direct way to study the formation and evolution of radio jets associated with the accretion onto massive black holes. We report preliminary results of our seven year VLBA observational…
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.…
By fitting high-quality and simultaneous multi-wavelength (MWL) spectral energy distributions (SEDs) at multiple epochs with a one-zone leptonic jet model, we study jet properties of the three famous blazars Mrk 421, 3C 454.3 and 3C 279. In…
We examine a model for the observed temporal variability of powerful blazars in the $\gamma$-ray band in which the dynamics is described in terms of a stochastic differential equation, including the contribution of a deterministic drift and…
Observations of jets from quasars and other types of accreting black hole are briefly summarized. The importance of beaming and $\gamma$-ray observations for understanding the origin of these jets is emphasised. It is argued that both the…
Blazars - active galaxies with the jet pointing at Earth - emit across all electromagnetic wavelengths. The so-called one-zone model has described well both quiescent and flaring states, however it cannot explain the radio emission. In…
The properties of relativistic radio jets are thought to be closely connected with the properties of accretion disks in active galactic nuclei. We explore this issue using a sample of 35 blazars with very-long baseline observations, for…
The radiation we observe from blazars is most likely the product of the transformation of bulk kinetic energy into random energy. This process must have a relatively small efficiency (e.g. 10%) if jets are to power the extended…
Recent multi-wavelength observations of 3C454.3, in particular during its giant outburst in 2005, put severe constraints on the location of the 'blazar zone', its dissipative nature, and high energy radiation mechanisms. As the optical,…
The polarimetric measurement on the prompt phase of GRB 100826A shows that the polarization angle changes $\sim 90^{\circ}$ between two adjacent time intervals. We will show that this phenomenon can be naturally interpreted in the framework…
Relativistic jets of radio loud active galactic nuclei (AGN) produce highly directed, intense beams of radiation. A fraction of this beamed radiation scatters on the thermal plasma generally surrounding an AGN. The morphology of the…
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…
The jet cores in blazars are resolved and found to harbour an edge brightened structure where the jet base appears extended at sides compared to its propagation axis. This peculiar phenomenon invites various explanations. We show that the…
The phenomenology of gamma-ray bright blazars can be accounted for by a sequence in the source power and intensity of the diffuse radiation field surrounding the relativistic jet. Correspondingly, the equilibrium particle distribution peaks…
We discuss the physical properties of four quasar jets imaged with the Chandra X-ray Observatory in the course of a survey for X-ray emission from radio jets. These objects have sufficient counts to study their spatially resolved…