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We aim to investigate the overall properties of the ICRF3 with the help of the Gaia Data release 2 (Gaia DR2). This could serve as an external check of the quality of the ICRF3. The radio source positions of the ICRF3 catalog were compared…

Instrumentation and Methods for Astrophysics · Physics 2020-02-05 Niu Liu , Sebastien Lambert , Zi Zhu , Jia. -Cheng. Liu

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…

Astrophysics · Physics 2007-05-23 Leonid Petrov , David Grodon , Anthony Beasley , Ed Fomalont

We have used the Very Large Array, linked with the Pie Town Very Long Baseline Array antenna, to determine astrometric positions of 19 radio stars in the International Celestial Reference Frame (ICRF). The positions of these stars were…

With the establishment of the AUT University 12m radio telescope at Warkworth, New Zealand has now become a part of the international Very Long Baseline Interferometry (VLBI) community. A major product of VLBI observations are images in the…

Instrumentation and Methods for Astrophysics · Physics 2011-10-26 Stuart Weston , Tim Natusch , Sergei Gulyaev

In the framework of the "Groupe de Recherches de G\'eod\'esie Spatiale" (GRGS), a rigorous combination of the data from five space geodetic techniques (VLBI, GPS, SLR, LLR and DORIS) is routinely applied to simultaneously determine a…

Astrophysics · Physics 2008-12-18 G. Bourda , P. Charlot , R. Biancale

VLBI measurements of the absolute proper motions of 23 radio stars have been collected from published data. These are stars with maser emission, or very young stars, or asymptotic-giant-branch stars. By comparing these measurements with the…

Astrophysics of Galaxies · Physics 2015-03-03 V. V. Bobylev

By linking widely separated radio dishes, the technique of very long baseline interferometry (VLBI) can greatly enhance angular resolution in radio astronomy. However, at any given moment, a VLBI array only sparsely samples the information…

Very long baseline interferometry (VLBI) is a powerful technique that can achieve sub-milliarcsecond resolution. However, it requires complex and often manual post-correlation calibration to correct for instrumental, geometric, and…

Instrumentation and Methods for Astrophysics · Physics 2025-12-01 Diego Álvarez-Ortega , Carolina Casadio , Felix M. Pötzl , Avinash Kumar , Michael Janssen

Very long baseline radio interferometry (VLBI) with ground-based observatories is limited by the size of Earth, the geographic distribution of antennas, and the transparency of the atmosphere. In this whitepaper, we present Capella, a…

Instrumentation and Methods for Astrophysics · Physics 2024-06-28 Sascha Trippe , Taehyun Jung , Jung-Won Lee , Jan Wagner , Jeong-Yeol Han , Wonseok Kang , Jae-Hyun Kyeong , Junghwan Oh , Jae-Young Kim , Jongho Park , Jeffrey A. Hodgson

The next generation of very long baseline interferometry (VLBI) is stepping into the era of microarcsecond ($\mu$as) astronomy, and pushing astronomy, especially astrometry, to new heights. VLBI with the Square Kilometre Array (SKA),…

Astrophysics of Galaxies · Physics 2024-04-24 Yingjie Li , Ye Xu , Jingjing Li , Shuaibo Bian , Zehao Lin , Chaojie Hao , Dejian Liu

The VLBI Global Observing System, which is the next generation of geodetic VLBI and is called VGOS, observes simultaneously at four frequency bands in the range 3.0--10.7 GHz (expected to be extended to 14 GHz). Because source structure…

Astrophysics of Galaxies · Physics 2022-07-20 Ming H. Xu , Tuomas Savolainen , James M. Anderson , Niko Kareinen , Nataliya Zubko , Susanne Lunz , Harald Schuh

Aims. We use near-infrared, ground-based data from the VISTA Variables in the Via Lactea (VVV) survey to indirectly extend the astrometry provided by the Gaia catalog to objects in heavily-extincted regions towards the Galactic bulge and…

Astrophysics of Galaxies · Physics 2024-07-03 M. Griggio , M. Libralato , A. Bellini , L. R. Bedin , J. Anderson , L. C. Smith , D. Minniti

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 present the results of the pilot observations of the Deep Extragalactic VLBI-Optical Survey (DEVOS). Our ultimate aim is to collect information on compact structures in a large sample of extragalactic radio sources (~10000 objects) up to…

Astrophysics · Physics 2009-11-13 L. Mosoni , S. Frey , L. I. Gurvits , M. A. Garrett , S. T. Garrington , Z. I. Tsvetanov

VLBI astrometry allows coordinates of celestial radio sources to be determined with submilliarcsecond accuracy. In particular, with differential VLBI astrometry, the standard errors of relative positions and proper motions can be as small…

Astrophysics · Physics 2007-05-23 Norbert Bartel

AIMS: An alternative to the traditional method for modeling kinematics of the Earth's rotation is proposed. The purpose of developing the new approach is to provide a self-consistent and simple description of the Earth's rotation in a way…

Astrophysics · Physics 2009-11-11 L. Petrov

Pulsar positions can be measured with high precision using both pulsar timing methods and very-long-baseline interferometry (VLBI). Pulsar timing positions are referenced to a solar-system ephemeris, whereas VLBI positions are referenced to…

Our present relativistic part of the geodetic VLBI model for Earthbound antennas is a consensus model which is considered as a standard for processing high-precision VLBI observations. It was created as a compromise between a variety of…

Instrumentation and Methods for Astrophysics · Physics 2017-10-26 Michael Soffel , Sergei Kopeikin , Wen-Biao Han

Optical positions from the SuperCOSMOS Sky Survey have been compared in detail with accurate radio positions that define the second realisation of the International Celestial Reference Frame (ICRF2). The comparison was limited to the IIIaJ…

Instrumentation and Methods for Astrophysics · Physics 2015-06-18 Adam Schaefer , Richard Hunstead , Helen Johnston
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