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Related papers: Precise geodesy with the Very Long Baseline Array

200 papers

Very Long Baseline Interferometry (VLBI) observations can provide the position of compact radio sources with an accuracy of order 50 micro-arcseconds. This is sufficient to measure the trigonometric parallax and proper motions of any object…

Astrophysics of Galaxies · Physics 2015-06-12 Laurent Loinard

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…

Astrophysics of Galaxies · Physics 2025-01-31 Ming Hui Xu , Patrick Charlot

Very Long Baseline Interferometry (VLBI) offers unrivalled resolution in studies of celestial radio sources. The subjects of interest of the IAU Symposium No. 356, the Active Galactic Nuclei (AGN) of all types, constitute the major…

Instrumentation and Methods for Astrophysics · Physics 2021-02-03 Leonid I. Gurvits , Robert Beswick , Melvin Hoare , Ann Njeri , Jay Blanchard , Carla Sharpe , Adrian Tiplady , Aletha de Witt

Many of the compact extragalactic radio sources that are used as fiducial points to define the celestial reference frame are known to have proper motions detectable with long-term geodetic/astrometric Very Long Baseline Interferometry…

Cosmology and Nongalactic Astrophysics · Physics 2013-04-16 A. Moór , S. Frey , S. B. Lambert , O. Titov , J. Bakos

This paper presents the fifth part of the Very Long Baseline Array (VLBA) Calibrator Survey (VCS), containing 569 sources not observed previously with very long baseline interferometry in geodetic or absolute astrometry programs. This…

Astrophysics · Physics 2008-11-26 Y. Y. Kovalev , L. Petrov , E. B. Fomalont , D. Gordon

This paper presents the third extension to the Very Large Baseline Array (VLBA) Calibrator Survey, containing 360 new sources not previously observed with very long baseline interferometry (VLBI). The survey, based on three 24 hour VLBA…

Astrophysics · Physics 2011-07-18 L. Petrov , Y. Y. Kovalev , E. Fomalont , D. Gordon

Very Long Baseline Interferometry (VLBI) observations can provide the position of compact radio sources with an accuracy of order 50 micro-arcseconds. This is sufficient to measure the trigonometric parallax and proper motions of any object…

Astrophysics of Galaxies · Physics 2011-03-07 L. Loinard , A. J. Mioduszewski , R. M. Torres , S. Dzib , L. F. Rodriguez , A. F. Boden

The first Search for Extra-Terrestrial Intelligence (SETI) conducted with Very Long Baseline Interferometry (VLBI) is presented. By consideration of the basic principles of interferometry, we show that VLBI is efficient at discriminating…

Instrumentation and Methods for Astrophysics · Physics 2015-06-05 H. Rampadarath , J. S. Morgan , S. J. Tingay , C. M. Trott

Context. We highlight the capabilities of the geodetic VLBI technique to test General relativity in the classical astrometric style, i.e., measuring the deflection of light in the vicinity of the Sun. Aims. In previous studies, the…

For Very Long Baseline Interferometry (VLBI), the fringe spacing is extremely narrow compared to the field of view imposed by the primary beam of each element. This means that an extremely large number of resolution units can potentially be…

Instrumentation and Methods for Astrophysics · Physics 2013-02-26 John S. Morgan , F. Mantovani , A. T. Deller , W. Brisken , W. Alef , E. Middelberg , M. Nanni , S. J. Tingay

The Caltech-Jodrell Bank very long baseline interferometry (VLBI) Surveys give detailed 5 GHz VLBI images of several hundred milliarcsecond (mas) radio sources, and the full width at half-maximum angular sizes of the corresponding compact…

Astrophysics · Physics 2009-11-13 J. C. Jackson

Results of VLBI and GPS observations were analyzed with goal to investigate differences in observed baseline length derived from both techniques. VLBI coordinates for European stations were obtained from processing of all available…

Geophysics · Physics 2011-02-04 Zinovy Malkin , Natalia Panafidina , Elena Skurikhina

Extension of radio interferometric baselines into space is inevitable if a diffraction-limited angular resolution defined by the Earth diameter at a given observing wavelength limits a pursuit of specific scientific goals. This was…

Instrumentation and Methods for Astrophysics · Physics 2018-10-03 Leonid I. Gurvits

We report on recent technical developments in the front- and back-ends for the four 20 m radio telescopes of the Japanese Very-Long-Baseline Interferometry (VLBI) project, VLBI Exploration of Radio Astrometry (VERA). We present a brief…

Instrumentation and Methods for Astrophysics · Physics 2022-12-21 Yoshiaki Hagiwara , Kazuhiro Hada , Mieko Takamura , Tomoaki Oyama , Aya Yamauchi , Syunsaku Suzuki

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…

Cosmology and Nongalactic Astrophysics · Physics 2013-09-26 K. E. Gabanyi , N. Marchili , T. P. Krichbaum , L. Fuhrmann , P. Muller , J. A. Zensus , X. Liu , H. G. Song

The modern Very Long Baseline Interferometry (VLBI) relativistic delay model, as documented in the IERS Conventions refers to the time epoch when the signal passes one of two stations of an interferometer baseline (selected arbitrarily from…

Instrumentation and Methods for Astrophysics · Physics 2021-01-22 Oleg Titov , Alexei Melnikov , Yulia Lopez

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…

Astrophysics · Physics 2007-05-23 E. Ros

Interferometers require accurate determination of the array configuration in order to produce reliable observations. A method is presented for finding the maximum-likelihood estimate of the telescope geometry, and of other instrumental…

Astrophysics · Physics 2009-11-07 Klaus Maisinger , M. P. Hobson , Richard D. E. Saunders , Keith J. B. Grainge

The internet has been used for data transfer in radio astronomy ever since its inception; however it is only recently that network bandwidth capability means that the internet becomes competitive with traditional forms of data storage. Very…

Instrumentation and Methods for Astrophysics · Physics 2014-11-20 R. E. Spencer , R. Hughes-Jones , M. Strong , S. Casey , A. Rushton , P. Burgess , S. Kershaw , C. Greenwood