395 citations · 2.4k across the 119 of their papers we have counts for
18 papers · 1 filter
The Apparent "Angular Size - Frequency" Dependence in ~3000 Parsec-scale Extragalactic Jets
J. Yang, L. I. Gurvits, S. Frey +1
The upper envelope of the amplitude of the VLBI visibility function usually represents the most compact structural pattern of extragalactic radio sources, in particular, the "core-…
A close look at compact triple radio sources
D. Cseh, A. Fuhl, S. Frey
We show an archival 1.4-GHz Very Large Array (VLA) image of the core-dominated triple (CDT) radio source J1628+3906, along with a recent high-resolution 5-GHz Very Long Baseline In…
Identification of Potential Weak Target Radio Quasars for ASTRO-G In-Beam Phase-Referencing
S. Frey, K. E. Gabanyi, Y. Asaki
We apply an efficient selection method to identify potential weak Very Long Baseline Interferometry (VLBI) target quasars simply using optical (SDSS) and low-resolution radio (FIRS…
High-resolution double morphology of the most distant known radio quasar at z=6.12
S. Frey, L. I. Gurvits, Z. Paragi +1
Context: The highest redshift quasars at z>~6 receive considerable attention since they provide strong constraints on the growth of the earliest supermassive black holes. They also…
High-Redshift Quasars at the Highest Resolution: VSOP Results
S. Frey, L. I. Gurvits, A. P. Lobanov +2
We studied the radio structure of high-redshift (z>3) quasars with VSOP at 1.6 and 5 GHz. These sources are the most distant objects ever observed with Space VLBI, at rest-frame fr…
Potential Targets for ASTRO-G In-Beam Phase-Referencing
S. Frey, K. E. Gabanyi
We show that as many as ~50 quasars with at least mJy-level expected flux density can be pre-selected as potential in-beam phase-reference targets for ASTRO-G. Most of them have ne…
Deep Extragalactic VLBI-Optical Survey (DEVOS) II. Efficient VLBI detection of SDSS quasars
S. Frey, L. I. Gurvits, Z. Paragi +3
Context: The Deep Extragalactic VLBI-Optical Survey (DEVOS) aims at constructing a large sample of compact radio sources up to two orders of magnitude fainter than those studied in…
The VSOP 5 GHz Active Galactic Nucleus Survey: V. Imaging Results for the Remaining 140 sources
R. Dodson, E. B. Fomalont, K. Wiik +21
In February 1997, the Japanese radio astronomy satellite HALCA was launched to provide the space-bourne element for the VLBI Space Observatory Programme (VSOP) mission. Approximate…
The VSOP Survey: Final individual results + Final aggregate results
R. Dodson, S. Horiuchi, W. Scott +10
In February 1997 the Japanese radio astronomy satellite HALCA was launched to provide the space-borne element for the VSOP mission. HALCA provided linear baselines three-times grea…
VLBI surveys
S. Frey
Systematic surveys of astronomical objects often lead to discoveries, but always provide invaluable information for statistical studies of well-defined samples. They also promote f…
Dual-frequency VSOP Imaging of a High-redshift Radio Quasar PKS 1402+044
Jun Yang, Leonid Gurvits, Andrei Lobanov +2
Based on the VLBI Space Observatory Programme (VSOP) observations at 1.6 and 5 GHz, we find that the luminous high-redshift (z=3.215) quasar PKS 1402+044 (J1405+0415) has a pronoun…
Celestial positions in radio and optical
S. Frey, P. Veres, K. Vida
We discuss the importance of the direct link between the most accurate radio and optical reference frames that will become possible with the next-generation space astrometry missio…
Deep Extragalactic VLBI-Optical Survey (DEVOS): I. Pilot MERLIN and VLBI observations
L. Mosoni, S. Frey, L. I. Gurvits +3
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…
High-resolution radio imaging of the most distant radio quasar SDSS J0836+0054
S. Frey, Z. Paragi, L. Mosoni +1
We observed SDSS J0836+0054, the most distant radio-loud quasar known at present (z=5.774) with the European Very Long Baseline Interferometry (VLBI) Network at the 5 GHz frequency…
The highest redshift radio quasar as seen with the EVN and the VLA
S. Frey, Z. Paragi, L. Mosoni +1
We report on European VLBI Network (EVN) and Very Large Array (VLA) observations of SDSS J0836+0054, the most distant radio-loud quasar known at present z=5.774). The source, with…
The VSOP 5 GHz AGN Survey: III. Imaging Results for the First 102 Sources
W. K. Scott, E. B. Fomalont, S. Horiuchi +17
The VSOP mission is a Japanese-led project to study radio sources with sub-milliarcsec resolution using an orbiting 8 m telescope, HALCA, along with global arrays of Earth-based te…
Radio structure of the most distant radio-detected quasar at the ten milli- arcsecond scale
S. Frey, L. Mosoni, Z. Paragi +1
We present a high resolution radio image of SDSS 0836+0054 identified recently as the most distant radio-detected quasar at a redshift of z=5.82. The observation was carried out wi…
Dual-Frequency VSOP Observations of AO 0235+164
S. Frey, L. I. Gurvits, D. R. Altschuler +6
AO 0235+164 is a very compact, flat spectrum radio source identified as a BL Lac object at a redshift of z=0.94. It is one of the most violently variable extragalactic objects at b…