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Related papers: GPS radio sources: new optical observations and an…

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We present results of EVN observations of eleven GHz-Peaked-Spectrum (GPS) radio sources at 2.3/8.4 GHz. These sources are from the classical ''bright'' GPS source samples with peak flux densities $>$ 0.2 Jy and spectral indices $\alpha <…

Astrophysics · Physics 2007-05-23 L. Xiang , D. Dallacasa , P. Cassaro , D. Jiang , C. Reynolds

We present optical identifications and redshifts for seventeen new high-redshift radio sources. Fifteen of these sources are radio galaxies; the remaining two are high-redshift, steep-spectrum, radio-loud quasars. These objects were…

Compact steep-spectrum radio sources and giga-hertz peaked spectrum radio sources (CSS/GPS) are generally considered to be mostly young radio sources. In recent years we studied at many wavelengths a sample of these objects selected from…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 C. Fanti , R. Fanti , A. Zanichelli , D. Dallacasa , C. Stanghellini

A new version of the Optical Characteristics of Astrometric Radio Sources (OCARS) catalog is presented. This compiled catalog includes radio sources observed in different VLBI programs and experiments that result in source position…

Instrumentation and Methods for Astrophysics · Physics 2018-11-29 Zinovy Malkin

Continuing our program of spectroscopic observations of ICRF sources, we present redshifts for 120 quasars and radio galaxies. Data were obtained with five telescopes: the 3.58m ESO New Technology Telescope (NTT), the two 8.2m Gemini…

Cosmology and Nongalactic Astrophysics · Physics 2013-05-15 Oleg Titov , Laura M. Stanford , Helen M. Johnston , Tapio Pursimo , Richard W. Hunstead , David L. Jauncey , K. Maslennikov , A. Boldycheva

High-redshift radio-loud quasars are used to, among other things, test the predictions of cosmological models, set constraints on black hole growth in the early universe and understand galaxy evolution. Prior to this paper, 20 extragalactic…

We report the results of the spectroscopic observations carried out at the SAO RAS 6-m telescope for the optical components of nine new extended radio sources found in the NVSS catalog. The measured redshifts of the host galaxies are in the…

Astrophysics of Galaxies · Physics 2015-06-23 V. R. Amirkhanyan , V. L. Afanasiev , A. V. Moiseev

High-redshift quasars are important to study galaxy and active galactic nuclei (AGN) evolution, test cosmological models, and study supermassive black hole growth. Optical searches for high-redshift sources have been very successful, but…

We present the results of HI and OH absorption measurements towards a sample of radio sources using the Arecibo 305-m telescope and the GMRT. In total, 27 radio sources were searched for associated 21-cm HI absorption. One totally new HI…

Astrophysics · Physics 2009-11-11 Neeraj Gupta , C. J. Salter , D. J. Saikia , T. Ghosh , S. Jeyakumar

From observations with the 6-m BTA telescope at SAO RAS, we have determined spectroscopic redshifts of seven optical objects whose coordinates coincide with those of radio sources from the list of IVS (International VLBI Service for Geodesy…

Cosmology and Nongalactic Astrophysics · Physics 2011-04-07 Kirill Maslennikov , Alexandra Boldycheva , Zinovy Malkin , Oleg Titov

The Australia Telescope 20GHz (AT20G) survey was used to select a complete sample of 656 Gigahertz Peaked Spectrum (GPS) sources with spectral turnovers above 5GHz. The AT20G has near simultaneous observations at 4.8, 8.6 and 20GHz, which…

Astrophysics of Galaxies · Physics 2009-11-13 P. J. Hancock

The Westerbork Northern Sky Survey (WENSS) has been used to select a sample of Gigahertz Peaked Spectrum (GPS) radio sources at flux densities one to two orders of magnitude lower than bright GPS sources investigated in earlier studies.…

Our current understanding of radio-loud AGN comes predominantly from studies at frequencies of 5 GHz and below. With the recent completion of the Australia Telescope 20 GHz (AT20G) survey, we can now gain insight into the high-frequency…

We used the Australia Telescope Compact Array (ATCA) to obtain 40 GHz and 95 GHz observations of a number of sources that were selected from the Australia Telescope Compact Array 20 GHz (AT20G) survey . The aim of the observations was to…

Astrophysics of Galaxies · Physics 2015-05-19 Paul J. Hancock , Elaine M. Sadler , Elizabeth K. Mahony , Roberto Ricci

We report the results of a CGRO multi-instrument series of observations of the unidentified gamma-ray source 2CG 135+1 and of its possible counterpart, the peculiar radio source GT 0236+610 coincident with the Be star LSI+61 303. We…

We present an analysis of the properties of optical counterparts of radio sources down to 1 mJy. Optical identifications have been obtained by matching together objects from the APM and FIRST surveys over the region $148.13^\circ\simlt {\rm…

Astrophysics · Physics 2009-11-06 M. Magliocchetti , S. J. Maddox

We defined a sub-sample of twelve GPS sources which have not been observed with the VLBI before, from the Parkes half-Jansky sample, and carried out VLBI observations at 1.6 GHz and 5 GHz with the European VLBI Network (EVN) in 2006 and…

Cosmology and Nongalactic Astrophysics · Physics 2011-01-25 L. Cui , X. Liu , J. Liu , H. -G. Song , Z. Ding

We present a sample of 1317 Infrared-Faint Radio Sources (IFRSs) that, for the first time, are reliably detected in the infrared, generated by cross-correlating the Wide-Field Infrared Survey Explorer (WISE) all-sky survey with major radio…

Radio surveys typically sample extragalactic sources in higher redshift regimes than is typical for optical surveys, resulting in many radio sources not having a detected optical counterpart. Over the next decade the Legacy Survey of Space…

Astrophysics of Galaxies · Physics 2024-09-24 Alex Tellez , Yjan Gordon , Keith Bechtol

We report on the results of X-ray and radio follow-up observations of two GeV gamma-ray sources 2FGL J0923.5+1508 and 2FGL J1502.1+5548, selected as candidates for high-redshift blazars from unassociated sources in the {\it Fermi} Large…

High Energy Astrophysical Phenomena · Physics 2015-06-16 Y. Takahashi , J. Kataoka , K. Niinuma , M. Honma , Y. Inoue , T. Totani , S. Inoue , T. Nakamori , K. Maeda