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We present an analysis of the spectral properties of the extragalactic radio sources in the nearly-complete VSA sample at 33GHz. Data from different surveys are used to study source spectra between 1.4 and 33GHz. We find that, in general,…

A sample of high-frequency peaker (HFP) candidates was formed from the AT20G catalog radio sources with spectral indices of the optically thick emission region $\alpha_{below}$ exceeding +0.5. A study of the spectral properties of the…

Cosmology and Nongalactic Astrophysics · Physics 2025-08-12 Elena Majorova , Olga Zhelenkova

We observed with the VLBA at 2.3 and 8.6 GHz a complete flux-density limited sample of 482 radio sources with declination >+75 degrees brighter than 200 mJy at 1.4 GHz drawn from the NVSS catalog. 34% of the sources show parsec-scale…

Astrophysics of Galaxies · Physics 2021-02-01 Alexander V. Popkov , Yuri Y. Kovalev , Leonid Y. Petrov , Yuri A. Kovalev

We present the source structure analysis of 11 calibrator sources in the Southern Hemisphere at 2.3 (S-band) and 8.4 GHz (X-band). We used multi-epoch very long baseline interferometry source maps available in the radio fundamental catalog…

Astrophysics of Galaxies · Physics 2023-01-16 Sanway Chatterjee , Sayan Basu , Dan MacMillan

We present observations at 1.7 and 8.4 GHz of two Compact Steep Spectrum (CSS) sources from a complete sample of low-intermediate power radio galaxies. 3C346 shows an asymmetric structure with a one-sided ``jet'' and ``hot spot''. Present…

Astrophysics · Physics 2009-10-28 W. D. Cotton , L. Feretti , G. Giovannini , T. Venturi , L. Lara , J. Marcaide , A. E. Wehrle

Variability of a galaxy's core radio source can be a significant consequence of AGN accretion. However, this variability has not been well studied, particularly at high radio frequencies. As such, we report on a campaign monitoring the high…

We present a new sample of 30 nearby (z<0.2) BL Lacs, selected to study the nuclear as well as the large scale properties of low power radio sources. In this first paper, we show and discuss new radio data taken with the VLA (19 objects at…

Astrophysics · Physics 2009-11-10 M. Giroletti , G. Giovannini , G. B. Taylor , R. Falomo

Multi-epoch GHz Very Long Baseline Interferometry (VLBI) data of the radio-loud quasar J1101+7225 were analyzed to estimate the proper motion of extended optically thin jet components. Two components separated from the core could be mapped…

Astrophysics · Physics 2009-11-11 J. -U. Pott , A. Eckart , M. Krips , T. P. Krichbaum , S. Britzen , W. Alef , J. A. Zensus

We propose that Gigahertz Peak Spectrum (GPS) and Compact Steep Spectrum (CSS) radio sources are the signposts of relativistic jet feedback in evolving galaxies. Our simulations of relativistic jets interacting with a warm, inhomogeneous…

VLA B-configuration snapshots have been obtained at 6cm and 20cm of 43 radio quasars with a range of known galaxy cluster environments. The radio sources are characterised by measures of morphology, flux, and size. These are studied as a…

Astrophysics · Physics 2009-10-28 J. B. Hutchings , A. C. Gower , S. Ryneveld , A. Dewey

From 43GHz VLBA observations of the pair of radio sources 1928+738 and 2007+777 we have demonstrated the feasibility of precision phase-delay differential astrometric techniques at millimeter wavelengths. For a pair of sources with 5…

Astrophysics · Physics 2007-05-23 J. C. Guirado , J. M. Marcaide , M. A. Perez-Torres , E. Ros

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

We present preliminary results from a VLBI survey at $\lambda=6 $cm of a sample of 35 sources with flux densities of 2 - 100 mJy. These sources were selected from the VLA FIRST survey at $\lambda = 20 $cm, in a 3 degree field around the…

Astrophysics · Physics 2009-10-31 S. T. Garrington , M. A. Garrett , A. Polatidis

We present initial results from a follow-up of the 9C survey, complete to 25 mJy at 15 GHz, designed to assemble and investigate a sample of young radiosources. We have made radio continuum maps of 111 sources at frequencies spanning 1.4-43…

We present the results of new observations of the enigmatic radio source B1144+352 with the WSRT at 1.4 GHz. The WENSS and NVSS surveys have revealed faint extended radio structures on Mpc-scales. We have investigated these large-scale…

Astrophysics · Physics 2007-05-23 A. P. Schoenmakers , A. G. de Bruyn , H. J. A. Rottgering , H. van der Laan

We present flux densities and polarization percentages of 159 radio galaxies based on nearly simultaneous VLA observations at four frequencies from 5 to 43GHz. This sample is selected from the high-frequency Australia Telescope 20GHz…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-18 Anna Sajina , Bruce Partridge , Tyler Evans , Shannon Stefl , Nicholas Vechik , Steve Myers , Simon Dicker , Phillip Korngut

The flat spectrum radio quasar 4C 38.41 showed a significant increase of its radio flux density during the period 2012 March - 2015 August which correlates with gamma-ray flaring activity. Multi-frequency simultaneous VLBI observations were…

Results of a pilot project with the participation of the "Kvazar-KVO" radio interferometry array in observations carried out with the European VLBI Network are presented. The aim of the project was to conduct and analyze multi-frequency…

Astrophysics of Galaxies · Physics 2018-11-19 P. A. Voitsik , A. B. Pushkarev , Y. Y. Kovalev , A. V. Plavin , A. P. Lobanov , A. V. Ipatov

We augment the two widest/deepest 1.4 GHz radio surveys: the NRAO VLA Sky Survey (NVSS) and the Faint Images of the Radio Sky at Twenty-Centimeters (FIRST), with the mean epoch in which each source was observed. We use these catalogs to…

Astrophysics of Galaxies · Physics 2015-05-28 Eran O. Ofek , Dale A. Frail

We present the first results of the VLBA Imaging and Polarimetry Survey (VIPS), a 5 GHz VLBI survey of 1,127 sources with flat radio spectra. Through automated data reduction and imaging routines, we have produced publicly available I, Q,…

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