Related papers: Possible evidence for double precessing nozzle str…

The kinematics and flux evolution of the superluminal knots in blazar 3C345 were interpreted in the framework of the precessing jet-nozzle scenario with a precessing common helical trajectory-pattern. We show that the jet in 3C345 precesses…

The precessing jet-nozzle scenario previously proposed was applied to interpret the VLBI-measured kinematics of five superluminal components (C4,C5,C9,C10 and C22) and their flux density evolution in blazar 3C345. It is shown that in the…

The precessing jet-nozzle scenario previously proposed was applied to model-fit the kinematics of five superluminal components (C19,C20,C21,B5 and B7) of jet-B in blazar 3C345. Based on a specific pattern for the the precessing common…

We try to propose a tentative relativistic jet model for explaining the entire radio-optical phenomena observed in blazar OJ287, which has been observed quasi-periodically with a cycle of about 12yr in its optical light curve. We…

The kinematic behavior of superluminal components observed at 43 GHz in blazar 3C454.3 were model-fitted with their light curves interpreted in terms of their Doppler-boosting effect. The relation between the flux evolution of superluminal…

Search for Doppler-boosting effect in flux evolution of superluminal components in blazars has been an important subject, which can help clarify their kinematic and emission properties. The kinematics and flux evolution observed at 15GHz…

VLBI observations have shown that the parsec-jet of 3C 345 is formed by several components, ejected from the core with superluminal velocities and travelling along bent trajectories on the plane of the sky. We interpret the differences in…

The quasar 3C345 is one of the best examples of extragalactic jet with superluminal components moving on helical paths. To get better constraints on the jet physics, we have imaged the source at the highest possible resolution, using…

The blazar AO 0235+164 is a key source for studying the interplay between multi-wavelength variability in its light curves and changes in the position angles and apparent velocities of its parsec-scale jet components. In this work, we…

An increasing number of blazars have been reported to show jet wobbling (i.e., non-regular rotations of the structural position angle of their innermost jets in the plane of the sky with amplitudes between 20 deg. and 50 deg., and time…

Radio loud active galactic nuclei present a remarkable variety of signs indicating the presence of periodical processes possibly originating in binary systems of supermassive black holes, in which orbital motion and precession are…

We have observed the QSO 3C345 with VSOP at 1.6GHz and 5GHz and with the VLBA at 22GHz and 43GHz, with 24 epochs in total, from 1997.40 to 1999.69. This study, combined with previous observations, reveals periodic changes in the…

We present a possible scenario for the ejection of a superluminal component in the jet of the Broad Line Radio Galaxy 3C111 in early 1996. VLBI observations at 15 GHz discovered the presence of two jet features on scales smaller than one…

We describe a scenario to explain blazar periodicities with timescales of $\sim$ few years. The scenario is based on a binary super-massive black hole (SMBH) system in which one of the two SMBH carries a jet. We discuss the various…

Light curves for more than century optical photometric observations of the blazar OJ 287 reveals strong flares with a quasi-period of about 12 years. For a long time, this period has been interpreted by processes in a binary black hole…

During the period 1966.5 - 2006.2 the 15GHz and 8GHz lightcurves of 3C454.3 (z=0.859) show a qsasi-periodicity of ~12.8 yr (~6.9 yr in the rest frame of the source) with a double-bump structure. This periodic behaviour is interpreted in…

Very Long Baseline Interferometry (VLBI) allows for high-resolution and high-sensitivity observations of relativistic jets, that can reveal periodicities of several years in their structure. We perform an analysis of long-term VLBI data of…

BL Lacertae is the prototype of the BL Lac class of active galactic nuclei, exhibiting intensive activity on parsec (pc) scales, such as intense core variability and multiple ejections of jet components. In particular, in previous works the…

We present a 16-month sequence of monthly polarimetric 43 GHz VLBA images of the radio galaxy 3C 120. The images probe the inner regions of the radio jet of this relatively nearby superluminal radio galaxy at a linear resolution of 0.07…

The 16th magnitude quasar 3C 345 (redshift z=0.5928) shows structural and emission variability on parsec scales around a compact unresolved radio core. For the last three decades it has been closely monitored with very long baseline…