Related papers: Radio structure of the blazar 1156+295 with sub-pc…
The blazar 1156+295 was observed by VLBA and EVN + MERLIN at 5 GHz in June 1996 and February 1997 respectively. The results show that the jet of the source has structural oscillations on the milliarcsecond scale and turns through a large…
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…
The high-redshift quasar PMN J0909+0354 ($z=3.288$) is known to have a pc-scale compact jet structure, based on global 5-GHz very long baseline interferometry (VLBI) observations performed in 1992. Its kpc-scale structure was studied with…
We report the discovery of an extremely curved jet in the radio-loud quasar PKS2136+141. Multi-frequency Very Long Baseline Array (VLBA) images show a bending jet making a turn-around of 210 degrees in the plane of the sky, which is, to our…
We investigate the pc-scale kinematics and kpc-scale radio morphology of the quasar PG 1302-102, which may harbour a sub-pc separation supermassive binary black hole system at its centre as inferred from optical variability. High-resolution…
We present full-track high-resolution radio observations of the jet of the galaxy M87 at 8 and 15 GHz. These observations were taken over three consecutive days in May 2009 using the Very Long Baseline Array (VLBA), one antenna of the Very…
We make use of VLBI observations of the radio jet in the quasar S5 0836+710 at different frequencies and epochs to study its properties. The jet shows helical structure at all frequencies. The ridge-line of the emission in the jet coincides…
Studying the internal structure of extragalactic jets is crucial for understanding their physics. The Japanese-led space VLBI project VSOP has presented an opportunity for such studies, by reaching baseline lengths of up to 36,000 km and…
Studying transversal structure in extragalactic jets is crucial for understanding their physics. The Japanese led space VLBI project VSOP has offered arguably the best opportunity for such studies, by reaching baseline lengths of up to…
We study the properties of the innermost jet of the flat spectrum radio quasar 1633+382 (4C~38.41) based on VLBI data from the radio monitoring observations of the Boston University VLBI program at 43~GHz. Analysis of the components…
The luminous high-redshift (z=2.17) quasar S50836+710 has been observed in October 1997 with the VSOP at 1.6 GHz and 5 GHz. We report here a previously unpublished image made from the data at 1.6 GHz and compare the structure of a…
The remarkable stability of extragalactic jets is surprising, given the reasonable possibility of the growth of instabilities. In addition, much work in the literature has invoked this possibility in order to explain observed jet structures…
Deep Very Large Array imaging of the quasar 3C\,345 at 4.86 and 8.44 GHz has been used to study the structure and linear polarization of its radio jet on scales ranging from 2 to 30 kpc. There is a 7--8 Jy unresolved core with spectral…
One of the open questions in extragalactic jet Astrophysics is related to the nature of the observed radio jet, namely whether it traces a pattern or the flow structure itself. In this paper I summarize the evidence collected for the…
We present VLA and first-epoch VLBA observations that are part of a program to study the parsec-scale radio structure of a sample of fifteen high-energy-peaked BL Lacs (HBLs). The sample was chosen to span the range of logarithmic X-ray to…
A significant fraction of compact radio-loud quasars display most of the characteristics of relativistically beamed, high-optical polarization blazars, yet are weakly polarized in the optical regime. We have used the VLBA at 22 and 43 GHz…
Radio-loud high-redshift quasars (HRQs), although only a few of them are known to date, are crucial for the studies of the growth of supermassive black holes (SMBHs) and the evolution of active galactic nuclei (AGN) at early cosmological…
The blazar 1156+295 was active at gamma-ray energies, exhibiting three prominent flares during the year 2010. Here, we present results using the combination of broadband (X-ray through mm single dish) monitoring data and radio band imaging…
Various quasi-periods for the long-term variability of the radio emission, optical emission, and structural position angle of the inner part of the parsec-scale jet in the blazar 0716+714 have been detected. The relationships between these…
In this paper, we present new VLBA observations of the radio jet in the quasar S5 0836+710 at 8 and 22 GHz. The identification of the ridge lines allow us to interpret the jet structure in terms of Kelvin-Helmholtz instability. Combined…