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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…

天体物理仪器与方法 · 物理学 2013-02-26 John S. Morgan , F. Mantovani , A. T. Deller , W. Brisken , W. Alef , E. Middelberg , M. Nanni , S. J. Tingay

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…

天体物理学 · 物理学 2007-05-23 M. A. Perez-Torres , J. M. Marcaide , J. C. Guirado , E. Ros , I. I. Shapiro , M. I. Ratner , E. Sardon

Very Long Baseline Interferometry is capable of measuring the gravitational delay caused by the Sun and planet gravitational fields. The post-Newtonian parameter $\gamma$ is now estimated with accuracy of $\sigma_{\gamma}=2\cdot 10^{-4}$…

天体物理仪器与方法 · 物理学 2013-11-04 Anastassia Girdiuk , Oleg Titov

Using very long baseline interferometry (VLBI) observations at (sub)millimeter wavelengths, the Event Horizon Telescope (EHT) currently achieves the finest angular resolution of any astronomical facility, necessary for imaging the…

天体物理仪器与方法 · 物理学 2025-10-23 Uri Rolls , Dominic W. Pesce , Paul Tiede , Lindy Blackburn , Iniyan Natarajan , Sheperd S. Doeleman

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…

The East Asia VLBI Network (EAVN) has recently enabled dual-polarization observations at $22$ and $43\,\mathrm{GHz}$. We present the first systematic verification of its polarimetric performance using EAVN observations of M87, 3C 279, 3C…

Multi-frequency VLBI observations allow studies of the continuum spectrum in the different parts of the parsec scale jets of AGN, providing information on the physical properties of the plasma and magnetic fields in them. Since VLBI…

天体物理学 · 物理学 2009-04-14 T. Savolainen , K. Wiik , E. Valtaoja , M. Tornikoski

A 20-hour VLBI observation with the NRAO VLBA and GBT in the NOAO Bootes field reaches an rms noise of 9 microJy per beam at 1.4 GHz. Three sources were detected at 10-milliarcsecond resolution within the GBT primary beam of FWHM 8.6',…

天体物理学 · 物理学 2007-05-23 M. A. Garrett , J. M. Wrobel , R. Morganti

Compact galactic and extragalactic radio sources can be imaged with an unsurpassed angular resolution of a few ten micro-arcseconds, adopting the observing technique of global millimeter VLBI. Here we present the Global Millimeter VLBI…

天体物理学 · 物理学 2007-05-23 T. P. Krichbaum , I. Agudo , U. Bach , A. Witzel , J. A. Zensus

The Seoul Radio Astronomy Observatory (SRAO) operates a 6.1-meter radio telescope on the Gwanak campus of Seoul National University. We present the efforts to reform SRAO to a Very Long Baseline Interferometry (VLBI) station, motivated by…

天体物理仪器与方法 · 物理学 2023-01-30 Naeun Shin , Yong-Sun Park , Do-Young Byun , Jinguk Seo , Dongkok Kim , Cheulhong Min , Hyunwoo Kang , Keiichi Asada , Wen-Ping Lo , Sascha Trippe

We study the faint radio population using wide-field very long baseline interferometry (VLBI) observations of 2865 known radio sources in the Cosmic Evolution Survey (COSMOS) field. The main objective of the project was to determine where…

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…

星系天体物理 · 物理学 2017-06-28 Kristóf Rozgonyi , Sándor Frey

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…

天体物理仪器与方法 · 物理学 2015-06-05 H. Rampadarath , J. S. Morgan , S. J. Tingay , C. M. Trott

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…

天体物理学 · 物理学 2009-11-13 Emil Lenc , Mike A. Garrett , Olaf Wucknitz , James M. Anderson , Steven J. Tingay

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…

Positions and maps of 1608 new compact sources were obtained in twelve sessions observed during 1994--2002 at the VLBA network at 8.4/2.3 GHz. These sources are recommended for use as calibrators for phase reference imaging and as geodetic…

天体物理学 · 物理学 2007-05-23 Leonid Petrov , David Grodon , Anthony Beasley , Ed Fomalont

We present results from observation, correlation and analysis of interferometric measurements between the three geodetic very long baseline interferometry (VLBI) stations at the Onsala Space Observatory. In total 25 sessions were observed…

天体物理仪器与方法 · 物理学 2021-05-05 Eskil Varenius , Rüdiger Haas , Tobias Nilsson

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…

宇宙学与河外天体物理 · 物理学 2013-04-16 A. Moór , S. Frey , S. B. Lambert , O. Titov , J. Bakos

The Gaia celestial reference frame (Gaia-CRF) will benefit from a close assessment with independent methods, such as Very Long Baseline Interferometry (VLBI) measurements of radio stars at bright magnitudes. However, obtaining full…

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…

天体物理学 · 物理学 2007-05-23 Z. Paragi , M. A. Garrett , B. Paczynski , C. Kouveliotou , A. Szomoru , C. Reynolds , S. M. Parsley , T. Ghosh