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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

The search for long-term variability of compact components of radio sources B0821+394 and B1812+412 over an interval of 10 years was carried out. The LPA LPI radio telescope with an operating frequency of 111 MHz was used for observations.…

High Energy Astrophysical Phenomena · Physics 2025-04-16 S. A. Tyul'bashev , I. V. Chashei , I. A. Grishanova , G. E. Tyul'basheva , I. A. Subaev

Volonteri et al. (2011) found that the number of radio-loud quasars above redshift 4 calculated from the luminosity function (based upon Swift/BAT observations) is much smaller than the number estimated from the known high-redshift beamed…

Astrophysics of Galaxies · Physics 2019-10-25 K. É. Gabányi , S. Frey , Z. Paragi , H. Cao , T. An , L. I. Gurvits , T. Sbarrato , K. Perger , K. Rozgonyi , Gy. Mező

Young radio-loud active galactic nuclei form an important tool to investigate the evolution of extragalactic radio sources. To study the early phases of expanding radio sources, we have constructed CORALZ, a sample of 25 compact…

Astrophysics of Galaxies · Physics 2015-05-13 N. de Vries , I. A. G. Snellen , R. T. Schilizzi , K. -H. Mack , C. R. Kaiser

We estimate ages and physical properties of powerful radio galaxies. An analysis of new multi-wavelength VLA observations of eleven very powerful classical double (FRIIb) radio galaxies with redshifts between 0.4 and 1.3 is presented. We…

We present the analysis of simultaneous multi-frequency Very Large Array (VLA) observations of 57 out of 61 sources from the ``faint'' high frequency peaker (HFP) sample carried out in various epochs. Sloan Digital Sky Survey (SDSS) data…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 M. Orienti , D. Dallacasa , C. Stanghellini

It has been known for nearly three decades that high redshift radio galaxies exhibit steep radio spectra, and hence ultra-steep spectrum radio sources provide candidates for high-redshift radio galaxies. Nearly all radio galaxies with z > 3…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 C. H. Ishwara-Chandra , S. K. Sirothia , Y. Wadadekar , S. Pal , R. Windhorst

The Rapid Temporal Survey (RATS) explores the faint, variable sky. Our observations search a parameter space which, until now, has never been exploited from the ground. Our strategy involves observing the sky close to the Galactic plane…

Astrophysics of Galaxies · Physics 2015-05-27 Thomas Barclay , Gavin Ramsay , Pasi Hakala , Ralf Napiwotzki , Gijs Nelemans , Stephen Potter , Ian Todd

Studying the long-term radio variability (timescales of months to years) of blazars enables us to gain a better understanding of the physical structure of these objects on sub-parsec scales, and the physics of super massive black holes. In…

(abridged) We use the 1.4 GHz VIMOS-VLA Deep Survey and the optical VVDS and the CFHT-LS to compare the properties of radio loud galaxies with respect to the whole population of optical galaxies. The availability of multiband photometry and…

We present a method for identifying radio stellar sources using their proper-motion. We demonstrate this method using the FIRST, VLASS, RACS-low and RACS-mid radio surveys, and astrometric information from Gaia Data Release 3. We find eight…

Solar and Stellar Astrophysics · Physics 2023-08-16 Laura Nicole Driessen , George Heald , Stefan W. Duchesne , Tara Murphy , Emil Lenc , James K. Leung , Vanessa A. Moss

We have carried out a dedicated transient survey of 300 deg$^2$ of the SDSS Stripe 82 region using the Giant Meterwavelength Radio Telescope (GMRT) at 150 MHz. Our multi-epoch observations, together with the TGSS survey, allow us to probe…

Instrumentation and Methods for Astrophysics · Physics 2019-10-24 A. Hajela , K. P. Mooley , H. T. Intema , D. A. Frail

We present the results of 5-GHz observations with the VLA A-array of a sample of candidate Compact Steep Spectrum sources (CSSs) selected from the S4 survey. We also estimate the symmetry parameters of high-luminosity CSSs selected from…

Astrophysics · Physics 2009-10-31 D. J. Saikia , S. Jeyakumar , C. J. Salter , P. Thomasson , R. E. Spencer , F. Mantovani

We define a complete sample of thirty-three GHz-Peaked-Spectrum (GPS) radio sources based on their spectral properties. We present measurements of the radio spectra and polarization of the complete sample and a list of additional GPS…

Astrophysics · Physics 2016-08-30 C. Stanghellini , C. P. O'Dea , D. Dallacasa , S. A. Baum , R. Fanti , C. Fanti

By cross-correlating large samples of galaxy clusters with publicly available radio source catalogs, we construct the volume-averaged radio luminosity function (RLF) in clusters of galaxies, and investigate its dependence on cluster…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 M. W. Sommer , K. Basu , F. Pacaud , F. Bertoldi , H. Andernach

Before and after every 12 hour synthesis observation, the Molonglo Observatory Synthesis Telescope (MOST) measures the flux densities of ~5 compact extragalactic radio sources, chosen from a list of 55 calibrators. From 1984 to 1996, the…

Astrophysics · Physics 2015-06-24 B. M. Gaensler , R. W. Hunstead

The spatial-frequency coverage of a radio interferometer is increased by combining samples acquired at different times and observing frequencies. However, astrophysical sources often contain complicated spatial structure that varies within…

Instrumentation and Methods for Astrophysics · Physics 2015-06-11 U. Rau

Our VLA observations of the XMM-Newton/Chandra 13hr deep survey field (see Page et al., this proceedings) result in one of the two deepest 1.4GHz radio maps ever made. Within the 15' radius field covered by the deep X-ray data (0.19 sq…

This paper introduces a new program to find high-redshift radio galaxies in the southern hemisphere through ultra-steep spectrum (USS) selection. We define a sample of 234 USS radio sources with spectral indices alpha_408^843 < -1.0 and…

Astrophysics · Physics 2009-11-13 J. W. Broderick , J. J. Bryant , R. W. Hunstead , E. M. Sadler , T. Murphy

As part of the GLOSTAR survey we have used the VLA in its B-configuration to observe the part of the Galactic plane between longitudes of 28d and 36d and latitudes from -1d to +1d at the C-band (4--8 GHz). To reduce the contamination of…