Sub-Milliarcsecond Imaging of Quasars and Active Galactic Nuclei. IV. Fine-Scale Structure

  title={Sub-Milliarcsecond Imaging of Quasars and Active Galactic Nuclei. IV. Fine-Scale Structure},
  author={Yuri Y. Kovalev and Kenneth I. Kellermann and Matthew L. Lister and Daniel C. Homan and Ren{\'e} C. Vermeulen and M. H. Cohen and Eduardo Ros and Matthias Kadler and Andrew P. Lobanov and J. Anton Zensus and N. S. Kardashev and L. I. Gurvits and Margo F. Aller and H. D. Aller},
  journal={The Astronomical Journal},
  pages={2473 - 2505}
We have examined the compact structure in 250 flat-spectrum extragalactic radio sources using interferometric fringe visibilities obtained with the Very Long Baseline Array (VLBA) at 15 GHz. With projected baselines out to 440 Mλ, we are able to investigate source structure on typical angular scales as small as 0.05 mas. This scale is similar to the resolution of the VLBI Space Observatory Programme data obtained on longer baselines at a lower frequency and with somewhat poorer accuracy. For… 

Faint Radio Sources in the NOAO Boötes Field: VLBA Imaging and Optical Identifications

As a step toward investigating the parsec-scale properties of faint extragalactic radio sources, the Very Long Baseline Array (VLBA) was used at 5.0 GHz to obtain phase-referenced images of 76

Compact Bright Radio-loud AGNs. III. A Large VLBA Survey at 43 GHz

We present the results from the 43 GHz Very Long Baseline Array (VLBA) observations of 124 compact radio-loud active galactic nuclei (AGNs) that were conducted between 2014 November and 2016 May. The

A global 86 GHz VLBI survey

We present results from a large global VLBI(Very Long Baseline Interferometry) survey of compact radio sources at 86 GHz which started in October 2001. The main goal of the survey is to increase the


We present results from a large 86 GHz global very long baseline interferometry (VLBI) survey of compact radio sources. The main goal of the survey is to increase by factors of 3–5 the total number

Parsec-Scale Radio Structure and Broad Optical Emission Lines in a Complete Sample of 3CR Lobe-dominated Quasars

We present results from VLBI observations of 24 of the 25 lobe-dominated quasars (LDQs) in the 3CR complete sample and from optical spectrophotometry of 14 of these objects. The VLBI observations


We present Very Long Baseline Array (VLBA) images of 20 TeV blazars not previously well studied on the parsec scale. All 20 of these sources are high-frequency peaked BL Lac objects (HBLs).

Magnetic Fields in Quasar Cores. II.

Multifrequency polarimetry with the Very Long Baseline Array telescope has revealed absolute Faraday rotation measures (RMs) in excess of 1000 rad m-2 in the central regions of seven out of eight

Magnetic Fields in Quasar Cores

Multifrequency polarimetry with the Very Long Baseline Array telescope has revealed absolute Faraday rotation measures (RMs) in excess of 1000 rad m-2 in the central regions of the quasars 3C 273, 3C


We report on the first high-frequency very long baseline interferometry observations of the nearby broad absorption line quasar, Mrk 231. Three epochs of observations were achieved at 15 GHz and 22

Global Millimeter VLBI Array Survey of Ultracompact Extragalactic Radio Sources at 86 GHz

Very Long Baseline Interferometry (VLBI) observations at 86 GHz ($\sim 3$ mm) reach a resolution of about 50 micro arcsec and sample the scales as small as $10^{3}-10^{4}$ Schwarzschild radii of the



Very-long-baseline radio interferometry surveys of the compact structure in active galactic nuclei.

  • P. Wilkinson
  • Physics
    Proceedings of the National Academy of Sciences of the United States of America
  • 1995
Very-long-baseline radio interferometry (VLBI) imaging surveys have been undertaken since the late 1970s. The sample sizes were initially limited to a few tens of objects but the snapshot technique

VLA observations of a complete sample of core-dominated radio sources

Maps with high dynamic range are presented of a well-defined sample of powerful core-dominated radio sources, all of which have 5-GHz core flux densities >1 Jy. The maps were made at a frequency of

A multi-frequency VLBA polarization study of 3C 309.1

VLBA Imaging of NGC 4261: Symmetric Parsec-scale Jets and the Inner Accretion Region

We observed the nuclear region of NGC 4261 (3C 270) with VLBI to determine the morphology of the central radio source on parsec scales and in particular to see whether the inner radio axis remained

The VSOP 5 GHz Continuum Survey: The Prelaunch VLBA Observations

We have imaged with milliarcsecond resolution at 5 GHz 374 strong flat-spectrum radio sources north of declination -44° using the VLBA in 1996 June. The source sample was compiled from the source

The milliarcsecond structure of a complete sample of radio sources. II: First-epoch maps at 5 GHz

VLBI observations of the compact radio structure in a sample of 65 powerful extragalactic radio sources are presented. The sources are classified as very compact, compact, asymmetric, compact double,

The VSOP 5 GHz AGN Survey I. Compilation and Observations

The VSOP mission is a Japanese-led project to image radio sources with sub-milliarcsec resolution by correlating the signal from the orbiting 8-m telescope, HALCA, with a global array of telescopes.

Multiwavelength Observations of a Flare from Markarian 501

We present multiwavelength observations of the BL Lacertae object Markarian 501 (Mrk 501) in 1997 between April 8 and April 19. Evidence of correlated variability is seen in very high energy (VHE; E

VLBI and Merlin observations of 3C 120 at 1. 7 GHz - superluminal motions beyond 0. 05 arcsec

The radio galaxy 3C 120 was observed at 1.7 GHz in 1982 and 1984 with VLBI arrays, and the results are reported. Significant changes in the radio structure are seen on scales out to 100 mas between

Survey of instantaneous 1-22 GHz spectra of 550 compact extragalactic objects with declinations from -30 deg to +43 deg

We present observational results for extra- galactic radio sources with milliarcsecond components, obtained with the 600 meter ring radio telescope RATAN{600 from 1st to 22nd December, 1997. For each