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From observations with the 6-m BTA telescope at SAO RAS, we have determined spectroscopic redshifts of seven optical objects whose coordinates coincide with those of radio sources from the list of IVS (International VLBI Service for Geodesy…

Cosmology and Nongalactic Astrophysics · Physics 2011-04-07 Kirill Maslennikov , Alexandra Boldycheva , Zinovy Malkin , Oleg Titov

We have assessed accuracy of estimates of Earth orientation parameters (EOP) determined from several very long baseline interferometry (VLBI) observing programs that ran concurrently at different networks. We consider that the root mean…

Geophysics · Physics 2026-03-09 Leonid Petrov , Christian Ploetz , Matthias Schartner

Very long baseline interferometry (VLBI) astrometry is used to determine the three-dimensional position and proper motion of astronomical objects. A typical VLBI astrometric campaign generally includes around ten observations, making it…

High Energy Astrophysical Phenomena · Physics 2025-07-30 Ashish Kumar , Adam T. Deller , Pankaj Jain , Javier Moldón

A short overview is given of the status of research on young extragalactic radio sources. We concentrate on Very Long Baseline Interferometric (VLBI), and space-VLBI results obtained with the VLBI Space Observatory Programme (VSOP). In…

Astrophysics · Physics 2008-02-15 I. A. G. Snellen

The AuScope geodetic Very Long Baseline Interferometry array consists of three new 12 m radio telescopes and a correlation facility in Australia. The telescopes at Hobart (Tasmania), Katherine (Northern Territory) and Yarragadee (Western…

A crucial part of a space mission for very-long baseline interferometery (VLBI), which is the technique capable of providing the highest resolution images in astronomy, is orbit determination of the mission's space radio telescope(s). In…

The angular distribution of the Cosmic Microwave Background Radiation (CMBR) in sky shows a dipole asymmetry, ascribed to the observer's motion (peculiar velocity of the solar system!), relative to the local comoving coordinates. The…

General Physics · Physics 2019-09-11 Ashok K. Singal

Radial velocity (RV) is crucial for stellar kinematics and Galactic archaeology. The Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) has obtained over ten million low-resolution spectra ($R \sim 1800$), yielding RVs for…

Solar and Stellar Astrophysics · Physics 2026-04-22 Jinming Zhang , Haibo Yuan , Zhijia Tian

Multi-epoch radio-interferometric observations of young stellar objects can be used to measure their displacement over the celestial sphere with a level of precision that currently cannot be attained at any other wavelength. In particular,…

Astrophysics · Physics 2008-04-28 Laurent Loinard , Rosa M. Torres , Amy J. Mioduszewski , Luis F. Rodriguez

Photometric observations of 235 extragalactic objects that are potential targets for the Space Interferometry Mission (SIM) are presented. Mean B, V, R, I magnitudes at the 5% level are obtained at 1 - 4 epochs between 2005 and 2007 using…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Roopesh Ojha , Norbert Zacharias , Gregory S. Hennessey , Ralph A. Gaume , Kenneth J. Johnston

High precision astrometric Space Very Long Baseline Interferometry (S-VLBI) at the low end of the conventional frequency range, i.e. 20cm, is a requirement for a number of high priority science goals. These are headlined by obtaining…

Instrumentation and Methods for Astrophysics · Physics 2015-06-15 R. Dodson , M. Rioja , Y. Asaki , H. Imai , X. -Y. Hong , Z. Shen

We present the VLA-COSMOS 3 GHz Large Project based on 384 hours of observations with the Karl G. Jansky Very Large Array (VLA) at 3 GHz (10 cm) toward the two square degree Cosmic Evolution Survey (COSMOS) field. The final mosaic reaches a…

Context. In order to understand galaxy evolution, it is essential to measure star formation rates (SFRs) across Cosmic times. Aims. The use of radio continuum emission as an extinction-free star formation tracer necessitates a good…

Astrophysics of Galaxies · Physics 2023-09-13 V. Heesen , S. Schulz , M. Brüggen , H. Edler , M. Stein , R. Paladino , A. Boselli , A. Ignesti , M. Fossati , R. -J. Dettmar

Astrometric accuracy of complex modern VLBI arrays cannot be calculated analytically. We study the astrometric accuracy of phase-referenced VLBI observations for the VLBA, EVN and global VLBI array by simulating VLBI data for targets at…

Astrophysics · Physics 2009-11-11 N. Pradel , P. Charlot , J. -F. Lestrade

Very long baseline interferometry (VLBI) makes it possible to recover images of astronomical sources with extremely high angular resolution. Most recently, the Event Horizon Telescope (EHT) has extended VLBI to short millimeter wavelengths…

Instrumentation and Methods for Astrophysics · Physics 2018-02-05 Katherine L. Bouman , Michael D. Johnson , Adrian V. Dalca , Andrew A. Chael , Freek Roelofs , Sheperd S. Doeleman , William T. Freeman

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

The importance of Very Long Baseline Interferometry (VLBI) for pulsar research is becoming increasingly prominent and receiving more and more attention. In this paper, we present pathfinding pulsar observation results with the Chinese VLBI…

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…

Astrophysics · Physics 2007-05-23 J. C. Guirado , J. M. Marcaide , M. A. Perez-Torres , E. Ros

Astrometry at centimeter wavelengths using Very Long Baseline Interferometry is approaching accuracies of ~1 uas for the angle between a target and a calibrator source separated by <1 degree on the sky. The BeSSeL Survey and the Japanese…

Instrumentation and Methods for Astrophysics · Physics 2023-01-13 Mark J. Reid
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