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VLBI observations of NRAO 530 at 22, 43 and 86GHz
NRAO 530 is an optically violent variable source and has been studied with multi-epoch multifrequency high-resolution very long baseline interferometry (VLBI) observations. NRAO... -
First Caltech-Jodrell Bank VLBI Survey. II.
We report lambda-18 cm VLBI observations made in 1991 September of a further 25 objects from the first Caltech-Jodrell Bank VLBI Survey (the CJ1 survey). The CJ1 sample is a... -
First Caltech-Jodrell Bank VLBI Survey. I.
We present the first results from the first Caltech-Jodrell Bank VLBI survey (the CJ1 survey). The CJ1 sample includes 135 radio sources with total flux density... -
Second Caltech-Jodrell Bank VLBI Survey. I.
We define the sample for the second Caltech-Jodrell Bank VLBI survey. This is a sample of 193 flat- or gigahertz-peaked-spectrum sources selected at 4850 MHz. This paper... -
Second Caltech-Jodrell Bank VLBI Survey. II.
This is the second of two papers presenting the Second Caltech- Jodrell Bank VLBI survey (CJ2). The CJ2 sample consists of 193 flat- and gigahertz-peaked-spectrum sources... -
Revisited jet bending in {gamma}-ray AGNs
We investigate the hypothesis that {gamma}-ray-quiet active galactic nuclei (AGNs) have a greater tendency for jet bending than {gamma}-ray-loud AGNs, revisiting the analysis of... -
VLBI monitoring of NGC 4258
We report a 3yr, 18 epoch, VLBI monitoring study of H_2_O masers in the subparsec, warped, accretion disk within the NGC 4258 AGN. Our immediate goals are to trace the geometry... -
IC 133 water vapor maser
We report on the results of a 14yr long VLBI study of proper motions in the IC 133 H_2_O maser source in the galaxy M33. -
Candidate ICRF flat-spectrum radio sources. III.
In extending our spectroscopic program, which targets sources drawn from the International Celestial Reference Frame (ICRF) Catalog, we have obtained spectra for ~160 compact,... -
Second epoch VLBA Calibrator Survey (VCS-II)
Six very successful Very Long Baseline Array (VLBA) calibrator survey campaigns were run between 1994 and 2007 to build up a large list of compact radio sources with positions... -
Spectroscopy of 120 emission-line ICRF2 candidates
Continuing our program of spectroscopic observations of International Celestial Reference Frame (ICRF) sources, we present redshifts for 120 quasars and radio galaxies. Data... -
Celestial Reference Frame at 24 and 43GHz. II
We have measured the submilliarcsecond structure of 274 extragalactic sources at 24 and 43 GHz in order to assess their astrometric suitability for use in a high-frequency... -
Celestial Reference Frame at 24 and 43 GHz
We present astrometric results for compact extragalactic objects observed with the Very Long Baseline Array at radio frequencies of 24 and 43GHz. Data were obtained from ten... -
Protostellar winds studied with water masers
Understanding the launching mechanism of winds and jets remains one of the fundamental challenges in astrophysics. The``Protostellar Outflows at the Earliest Stages'' (POETS)... -
Gaussian model fit components for 3C345
The flat-spectrum radio quasar 3C 345 has been showing gamma-ray activity since the mid-2000s along with activity across the electromagnetic spectrum. A gamma-ray burst in 2009... -
M87* EHT image
In April 2019, the Event Horizon Telescope (EHT) Collaboration reported the first-ever event-horizon-scale images of a black hole, resolving the central compact radio source in... -
Mini-cocoon in 3C84 RadioAstron discovery
We present RadioAstron space-based very long baseline interferometry (VLBI) observations of the nearby radio galaxy 3C84 (NGC1275) at the centre of the Perseus cluster. The... -
Spectral analysis of M87 jet
Because of its proximity and the large size of its black hole, M87 is one of the best targets for studying the launching mechanism of active galactic nucleus jets. Currently,... -
Blazar 3C 454.3 time variability
Measuring and inferring the key physical parameters of jets in active galactic nuclei (AGN) requires high-resolution very long baseline interferometry (VLBI) observations. Using... -
Jet collimation in NGC 1052
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...