相关论文: The source structure of 0642+449 detected from the…

Closure quantities measured by very long baseline interferometry (VLBI) observations are independent of instrumental and propagation instabilities and antenna gain factors, but are sensitive to source structure. A new method is proposed to…

Context: To investigate the differences between positions, as determined by optical (direct imaging) and Very Long Baseline Interferometry (VLBI) techniques, of extragalactic sources listed in the second realization of the International…

From 43GHz VLBA observations of the pair of radio sources 1928+738 and 2007+777 we have demonstrated the feasibility of precision phase-delay differential astrometric techniques at millimeter wavelengths. For a pair of sources with 5…

We present a multi-epoch and multi-frequency VLBI study of the compact radio source J0650+6001. In VLBI images the source is resolved into three components. The central component shows a flat spectrum, suggesting the presence of the core,…

Global VLBI observations at 5 GHz have been performed to study the source morphology in 10 compact steep-spectrum (CSS) sources selected from the Peacock & Wall catalogue with the aim of finding asymmetric structures produced by the…

We present multi-frequency radio continuum VLBI observations of the gravitational lens system B0218+357 carried out using a global VLBI network and the VLBA. The source has been observed with resolutions from 0.2 milliarcsec to 5…

This paper presents the catalog of correlated flux densities in three ranges of baseline projection lengths of 637 sources from a 43 GHz (Q-band) survey observed with the Korean VLBI Network. Of them, 623 sources have not been observed…

Active Galactic Nuclei (AGNs) observed with the technique of very long baseline interferometry (VLBI) are used as fiducial references on the sky to precisely measure the shape and orientation of the Earth. Their positions form a celestial…

We have measured the sub-milli-arcsecond 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 (CRF). Ten sessions of observations with…

Geodetic and astrometric VLBI has entered a new era with the implementation of the VLBI Global Observing System (VGOS). These broadband and dual linear polarization observations aim at an accuracy of station coordinates of 1 mm and a…

The next-generation, broadband geodetic very long baseline interferometry system, named VGOS, is developing its global network, and VGOS networks with a small size of 3--7 stations have already made broadband observations from 2017 to 2019.…

This paper presents the sixth part to the Very Long Baseline Array (VLBA) Calibrator Survey. It contains the positions and maps of 264 sources of which 169 were not previously observed with very long baseline interferometry (VLBI). This…

The IDV observations of S4 0917+624 were carried out monthly, from August 2005 to January 2010, with the Urumqi 25m radio telescope at 4.8 GHz. The quasar S4 0917+624 exhibits only very weak or no IDV during our 4.5 year observing interval.…

We present a catalogue of positions and correlated flux densities of 410 flat-spectrum, compact extragalactic radio sources, previously detected in the AT20G survey. The catalogue spans the declination range -90deg, -40deg and was…

Short time-scale flux density variations of flat spectrum radio sources are often explained by the scattering of radio waves in the turbulent, ionized Interstellar Matter of the Milky Way. One of the most convincing observational arguments…

We present preliminary results from a VLBI survey at $\lambda=6 $cm of a sample of 35 sources with flux densities of 2 - 100 mJy. These sources were selected from the VLA FIRST survey at $\lambda = 20 $cm, in a 3 degree field around the…

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 total number of objects accessible for…

We have used VLBA fringe visibility data obtained at 15 GHz to examine the compact structure in 250 extragalactic radio sources. For 171 sources in our sample, more than half of the total flux density seen by the VLBA remains unresolved on…

The use of the phase-delay improves substantially the accuracy obtained in VLBI astrometry with respect to the group-delay observable. Recently, Ros et al. (1999) have extended the related phase-connection technique to a triangle of radio…

We present an analysis of archival multi-frequency Very Large Array monitoring data of the two-image gravitational lens system CLASS B1600+434, including the polarization properties at 8.5 GHz. From simulating radio light curves…