Results 11 to 20 of about 424 (141)

A Comparative Study of VTEC Estimates Derived From S/X VLBI and VGOS Observations

Space Weather
The ionosphere, which strongly varies in time and space, is one of the largest error sources for microwave measurements, if not accounted for accurately.
Arno Rüegg, Grzegorz Kłopotek, Benedikt Soja   +2 more
doaj   +2 more sources

Astrometric Apparent Motion of High-redshift Radio Sources

The Astronomical Journal, 2023
Radio-loud quasars at high redshift ( z ≥ 4) are rare objects in the universe and rarely observed with Very Long Baseline Interferometry (VLBI). But some of them have flux density sufficiently high for monitoring of their apparent position.
Oleg Titov, Sándor Frey, Alexey Melnikov, Fengchun Shu, Bo Xia, Javier González, Belén Tercero, Leonid Gurvits, Aletha de Witt, Jamie McCallum, Mikhail Kharinov, Vladimir Zimovsky, Máté Krezinger   +12 more
doaj   +1 more source

VLBI Type Experimental Observation of GPS [PDF]

Journal of Astronomy and Space Sciences, 2010
As a preparatory study for Global Positioning System-Very Long Baseline Interferometry (GPS-VLBI) hybrid system, we examined if VLBI type observation of the GPS signal is realizable through a test experiment.
Younghee Kwak, Tetsuro Kondo, Jun Amagai, Tadahiro Gotoh, Tetsuo Sasao, Jungho Cho, Tuhwan Kim   +6 more
doaj   +1 more source

Very long baseline interferometry: accuracy limits and relativistic tests [PDF]

Proceedings of the International Astronomical Union, 2009
AbstractWe present a review on relativistic effects and best estimates of the relativistic PPN parameter γ obtained by analysis of data from the International VLBI Service for Geodesy and Astrometry (IVS). Relativistic implications are also considered in view of the upcoming new generation VLBI System: VLBI2010.
Heinkelmann, R., Schuh, H.
openaire   +3 more sources

Modeling Nearby Low-Luminosity Active-Galactic-Nucleus Jet Images at All VLBI Scales

Galaxies, 2022
Relativistic jets from nearby low-luminosity active-galactic-nuclei (LLAGN) were observed by Very-Long Baseline Interferometry (VLBI) across many orders of magnitude in space, from milliparsec to sub-parsec scales, and from the jet base in the vicinity ...
Hung-Yi Pu, Keiichi Asada, Masanori Nakamura   +2 more
doaj   +1 more source

Very-long-baseline radio interferometry (VLBI) observations of gamma-ray blazars: results from millimeter-VLBI observations. [PDF]

Proceedings of the National Academy of Sciences, 1995
VLBI observations of the extremely gamma-bright blazar PKS 0528+134 at 8, 22, 43, and 86 GHz reveal a strongly bent one-sided-core jet structure with at least three moving and two apparently stationary jet components. At the highest observing frequencies the brightest and most compact jet component (the VLBI core) is unresolved with an upper limit to ...
T P, Krichbaum, S, Britzen, K J, Standke, A, Witzel, C J, Schalinski, J A, Zensus   +5 more
openaire   +2 more sources

Rotation of Earth and determination of Earth orientation parameters [PDF]

Geodetski Glasnik, 2015
Earth's rotation and elements of the Earth's orientation, with emphasis on the determination of the parameters of the Earth's orientation were described.
Mirko Borisov, Miro Govedarica, Maja Orihan   +2 more
doaj   +1 more source

An Updated View of the Milky Way from Maser Astrometry

Universe, 2022
Astrometric observations of maser sources in the Milky Way, using the Very Long Baseline Interferometry (VLBI) technique, have been exploited to determine the spiral structure of our Galaxy. Several major spiral arms have now been pinpointed in the first
Katharina Immer, Kazi L. J. Rygl
doaj   +1 more source

Data Handling within the International VLBI Service

Data Science Journal, 2013
The International VLBI Service for Geodesy and Astrometry (IVS) is a globally operating service that coordinates and performs Very Long Baseline Interferometry (VLBI) activities through its constituent components.
Dirk Behrend
doaj   +1 more source

Modelling Very Long Baseline Interferometry (VLBI) observations

Journal of Geodesy and Geoinformation, 2012
Bu çalışmanın temel amacı Çok Uzun Baz Enterferometrisi VLBI sinyal gecikme modelinin teorik detaylarını Uluslararası Yer Dönüklük ve Referans Sistemleri Servisi IERS 2010 Konvansiyonları temelinde sunmaktır. Bu kapsamda sürekli parçalı lineer ofset CPWLO fonksiyonları ile gün‒içi zamansal çözünürlükte önceden belirlenmiş epoklarda, örneğin: Evrensel ...
Teke, K., Kayýkçi, E., Böhm, J., Schuh, H.   +3 more
openaire   +3 more sources