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The recent development of a relatively inexpensive 16-Gbps data-recording system based on commercial off-the-shelf technology and open-source software, along with parallel development in broadband Very Long Baseline Interferometry (VLBI)…

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

Studying transient phenomena with the Very Long Baseline Interferometry (VLBI) technique faces severe difficulties because the turnaround time of the experiments from the observations to the scientific result is rather long. The e-VLBI…

On 18 November 1993, we observed the QSO 1150+812 and the BL Lac object 1803+784, nearly 15\deg apart on the sky, with a VLBI array, simultaneously recording at 8.4 and 2.3 GHz. Using difference astrometry techniques, we determined the…

Black hole imaging challenges the 3rd generation space VLBI, the Very Long Baseline Interferometry, to operate on a 500 GHz band. The coherent integration time needed here is 450 s though the available space oscillators cannot offer more…

Instrumentation and Methods for Astrophysics · Physics 2021-09-20 V. Kudriashov , M. Martin-Neira , E. Lia , J. Michalski , P. Kant , D. Trofimowicz , M. Belloni , P. Jankovic , P. Waller , M. Brandt

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

The observation and imaging of hundreds or thousands of radio sources with the technique of very long baseline interferometry (VLBI) is a computationally intensive task. However, these surveys allow us to conduct statistical investigations…

Astrophysics of Galaxies · Physics 2017-06-28 Kristóf Rozgonyi , Sándor Frey

It is anticipated that future space-born missions, such as Gaia, will be able to determine in optical domain positions of more than 100,000 bright quasars with sub-mas accuracies that are comparable to very long baseline interferometry…

Instrumentation and Methods for Astrophysics · Physics 2013-06-13 Leonid Petrov

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

This paper introduces a new instrument enabling a novel combination of Earth measuring techniques: direct observations with the radio astronomical instruments to satellites of the global navigation satellite systems. Inter-technique biases…

Geophysics · Physics 2025-03-26 Lucia McCallum , David Schunck , Jamie McCallum , Tiege McCarthy

Very Long Baseline Interferometry (VLBI) combines the signals of telescopes distributed across thousands of kilometres to provide some of the highest angular resolution images of astrophysical phenomena. Due to computational expense,…

Instrumentation and Methods for Astrophysics · Physics 2025-04-30 Jack F. Radcliffe , J. P. McKean , C. Herbé-George , L. Coetzer , T. Matsepane

We report on the first wide-field, very long baseline interferometry (VLBI) survey at 90 cm. The survey area consists of two overlapping 28 deg^2 fields centred on the quasar J0226+3421 and the gravitational lens B0218+357. A total of 618…

Astrophysics · Physics 2009-11-13 Emil Lenc , Mike A. Garrett , Olaf Wucknitz , James M. Anderson , Steven J. Tingay

A relativistic delay model for space very long baseline interferometry (hereafter SVLBI) observation of sources at infinite distance is derived. In SVLBI, where one station is on a spacecraft, the orbiting station's maximum speed in an…

Instrumentation and Methods for Astrophysics · Physics 2014-06-19 Shi-Long Liao , Zheng-Hong Tang , Zhao-Xiang Qi

Very Long Baseline Interferometry (VLBI) provides high angular resolution images and has been used for stellar astrometry for decades. The DYNAMO-VLBA project utilizes the Very Long Baseline Array (VLBA) to study tight binary and multiple…

Solar and Stellar Astrophysics · Physics 2025-11-07 Jazmin Ordonez-Toro , Sergio A. Dzib , Laurent Loinard

Context. The current algorithms used for the calibration and analysis of very long baseline interferometry (VLBI) networks that only use linear polarizers (as is the case of the VLBI Global Observing System, VGOS) do not properly account…

Instrumentation and Methods for Astrophysics · Physics 2024-06-19 V. Pérez-Díez , I. Martí-Vidal , E. Albentosa-Ruiz , J. González-García , F. Jaron , T. Savolainen , M. H. Xu , R. Bachiller

The technique of Very Long Baseline Interferometry (VLBI) can provide accurate localization and unique physical information about radio transients. However, it is still underutilized due to the inherent difficulties of VLBI data analysis…

Instrumentation and Methods for Astrophysics · Physics 2018-03-09 K. V. Sokolovsky , M. Giroletti , S. Corbel , G. E. Anderson , B. W. Stappers

We experimentally demonstrate a novel interferometric architecture for next-generation gravity missions, featuring a laser ranging interferometer (LRI) that enables monoaxial transmission and reception of laser beams between two optical…

Finding a suitable very long baseline (VLBI) interferometer geometry is a key task in planning observations, especially imaging sessions. The main characteristic of the quality of VLBI imaging data is the (u, v)-coverage. In the case when…

Instrumentation and Methods for Astrophysics · Physics 2024-04-01 I. I. Bulygin , M. A. Shchurov , A. G. Rudnitskiy

Long baseline radio interferometers can provide some interesting opportunities for future SETI searches. Known advantages (compared to single dishes or beam-formed arrays), include the large reduction in false-positives due to the…

Instrumentation and Methods for Astrophysics · Physics 2018-10-18 M. A. Garrett

Global VLBI observations, to measure Earth orientation and station positions, are organised into 24-hour sessions. Each session has a bespoke schedule created, optimised for the particular time period and the station network that is…

Geophysics · Physics 2025-10-14 Tiege McCarthy , Lucia McCallum