Related papers: Millimeter VLBI and Variability in AGN Jets

We describe a new method which achieves high precision Very Long Baseline Interferometry (VLBI) astrometry in observations at millimeter wavelengths. It combines fast frequency-switching observations, to correct for the dominant…

We present a new centimeter polarimetric VLBI image of the BL Lac object 0735+178. This source exhibits one of the most pronounced curvatures observed in jets of AGNs, with two sharp apparent bends of 90 degrees within the inner 2…

We present the results of a VLBI Space Observatory Programme (VSOP) observation of the subparsec structure in Centaurus A at 4.9 GHz. Owing to its proximity, our Centaurus A space-VLBI image is one of the highest spatial resolution images…

Radio galaxies harbouring jetted active galactic nuclei are a frequent target of very-long-baseline interferometry (VLBI) because they play an essential role in exploring how jets form and propagate. Hence, only few have not been detected…

Simultaneous observations at multiple frequency bands have the potential to overcome the fundamental limitation imposed by the atmospheric propagation in mm-VLBI observations. The propagation effects place a severe limit in the sensitivity…

The study of jet launching in AGN is an important research method to better understand supermassive black holes (SMBHs) and their immediate surroundings. The main theoretical jet launching scenarios invoke either magnetic field lines…

We present measurements of proper motion of the sub-parsec scale jet at 22 GHz in the nearby FR I galaxy 3C 66B. Observations were made using the VLBA at six epochs over four years. A phase-referencing technique was used to improve the…

The European VLBI Network is a collaboration of the major radio astronomical institutes in Europe, Asia, South Africa and Puerto Rico. Established four decades ago, since then it has constantly improved its performance in terms made using…

The sub/millimeter wavelengths (86-690 GHz) very long baseline interferometry (VLBI) will provide $\sim5-40\ \mu$as angular resolution, $\sim10$ mJy baseline sensitivity, and $\sim 1\ \mu$as/yr proper motion precision, which can directly…

The kinematics of jets in active galactic nuclei (QSOs, BL Lacs, Radio Galaxies and Empty Field objects) on parsec scales is being studied with Very Long Baseline Array observations at 15 GHz of a sample of more than 170 radio sources. More…

The broad-line radio galaxy 3C 111 exhibited a major flux density outburst in 2007. Here, we present imaging and preliminary kinematic results of the jet, based on three millimetre-VLBI observations (86 GHz) using the Global Millimeter VLBI…

I review here the present observational efforts to study parsec-scale radio jets in active galactic nuclei with very-long-baseline interferometry (VLBI) as related to the new window to the Universe opened by the LAT instrument on-board the…

This white paper describes the science case for Very Long Baseline Interferometry (VLBI) and provides suggestions towards upgrade paths for the European VLBI Network (EVN). The EVN is a distributed long-baseline radio interferometric array,…

The recent development of a relatively inexpensive 16-Gbps data-recording system based on commercial off-the-shelf technology and open-source software, along with parallel development in broadband Very Long Baseline Interferometry (VLBI)…

Very long baseline interferometry (VLBI) provides the resolution needed to make precision measurements of a pulsar's parallax and proper motion. In making these measurements, the astronomer is faced with difficult calibration problems and a…

Polarization of radio emission in extragalactic jets at a sub-milliarcsecond angular resolution holds important clues for understanding the structure of the magnetic field in the inner regions of the jets and in close vicinity of the…

We present results from very-long-baseline-interferometry (VLBI) observations of the nucleus in the lobe-dominated quasar 3C207. These observations were completed at 8.4 or 10.7 GHz (X-band) from 1981 to 2010, spanning 29 years. The nucleus…

Previous research showed most BL Lac objects and some quasars have aligned VLBI-core and optical polarizations, although some of the AGNs also showed no obvious relationship between VLBI-core and optical polarization angles. This may…

We present Very Long Baseline Array (VLBA) observations of the radio source J1625+4134 at 22 and 15 GHz and analyze them in concurrence with other existing VLBI data on this source. The high resolution images at 15 and 22 GHz show a short…

We are in the process of obtaining VLBA polarisation data for the 135 MOJAVE-I Active Galactic Nuclei at four wavelengths in the 18-22cm band. These observations will enable studies of the evolution of the intensity and magnetic-field…