Related papers: AGN jets under the microscope: A divide?

We present 15 GHz stacked VLBA images of 373 jets associated with active galactic nuclei (AGN) having at least five observing epochs within a 20 yr time interval 1994-2015 from the MOJAVE programme and/or its precursor, the 2 cm VLBA…

The ATLAS collaboration has introduced and implemented a strategy for selecting and analyzing large-radius jets composed of skinny $R=0.2$ subjets in heavy ion collisions at the LHC. We show how measurements of these jets teach us about the…

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,…

BL Lac objects are active nuclei, hosted in massive elliptical galaxies, the emission of which is dominated by a relativistic jet closely aligned with the line of sight. This implies the existence of a parent population of sources with a…

Up to now, jet kinematic studies of radio quasars have barely reached beyond the redshift range at $z>3.5$. This significantly limits our knowledge of high-redshift jets, which can provide key information for understanding the jet nature…

Observational studies of collimation in jets in active galactic nuclei (AGN) are a key to understanding their formation and acceleration processes. We have performed an automated search for jet shape transitions in a sample of 367 AGN using…

Two types of radio emission are observed from X-ray binaries with jets. They have completely different characteristics and are associated with different kinds of ejections. One kind of emission has a flat or inverted spectrum indicating…

The synchrotron self-Compton (SSC) models and External Compton (EC) models of AGN jets with continually longitudinal and transverse bulk velocity structures are constructed. The observed spectra show complex and interesting patterns in…

We study the BL Lac objects detected in the one year all sky survey of the Fermi satellite, with a energy spectral slope alpha_gamma in the [0.1-100 GeV] band greater than 1.2. In the alpha_gamma vs gamma-ray luminosity plane, these BL Lacs…

We discuss a new VLBA program to investigate structural and polarization changes in the brightest AGN jets in the northern sky. Our study represents a significant improvement over previous surveys in terms of image fidelity, size, and…

We present the results of a number of high resolution radio observations of the AGN 1156+295. These include multi-epoch and multi-frequency VLBI, VSOP, MERLIN and VLA observations made over a period of 50 months. The 5 GHz MERLIN images…

In this chapter we review some aspects of X-ray binaries, particularly those presenting steady jets, i.e. microquasars. Because of their proximity and similarities with active galactic nuclei (AGN), galactic jet sources are unique…

With the increased sensitivity and resolution of radio interferometry the study of the collimation and acceleration region of jets in Active Galactic Nuclei (AGN) has come into focus within the last years. Whereas a large fraction of AGN…

Flat radio spectra with large brightness temperatures at the core of AGN and X-ray binaries are usually interpreted as the partially self-absorbed bases of jet flows emitting synchrotron radiation. Here we extend previous models of jets…

We analyze the parsec-scale jet kinematics from 2007 June to 2018 December of a sample of $\gamma$-ray bright blazars monitored roughly monthly with the Very Long Baseline Array at 43 GHz under the VLBA-BU-BLAZAR program. We implement a…

The $Fermi$ blazar observations show a strong correlation between $\gamma$-ray luminosities and spectral indices. BL Lac objects are less luminous with harder spectra than flat-spectrum radio quasars (FSRQs). Interestingly FSRQs are evident…

We discuss acceleration measurements for a large sample of extragalactic radio jets from the MOJAVE program which studies the parsec-scale jet structure and kinematics of a complete, flux-density-limited sample of Active Galactic Nuclei…

We used 15 GHz VLBA observations of 366 sources having at least 5 epochs within a time interval 1995-2013 from the MOJAVE program and/or its predecessor, the 2 cm VLBA Survey. For each source we produced a corresponding stacked image…

We re-examine the differences observed in the pc-scale magnetic field geometry of high and low optical polarization Quasars (HPQs, LPRQs) using the MOJAVE sample. We find that, as previously reported, HPQ jets exhibit predominantly…

The most extreme active galactic nuclei (AGN) are the radio active ones whose relativistic jet propagates close to our line of sight. These objects were first classified according to their emission line features into flat-spectrum radio…