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We present a sample of 40 Ultra Steep Spectrum (USS, $\alpha \leq -1.3$, $S_{\nu}\propto \nu^{\alpha}$) radio sources selected from the Westerbork in the Southern Hemisphere (WISH) catalog. The USS sources have been imaged in K--band at the…

We have used the upgraded Giant Metrewave Radio Telescope to map the Coma cluster of galaxies at 250-500 MHz and 1050-1450 MHz bands. These 6.26 arcsec and 2.18 arcsec resolutions observations allow detailed radio structures to be…

Astrophysics of Galaxies · Physics 2021-06-01 Dharam V. Lal

We performed observations with the Effelsberg 100-m radio telescope to measure flux densities and polarised emission of sources selected from the "Deep X-ray Radio Blazar Survey" (DXRBS) to better define their spectral index behaviour in…

Cosmology and Nongalactic Astrophysics · Physics 2011-07-28 Franco Mantovani , Marco Bondi , Karl-Heinz Mack

In this work, we study the optical properties of compact radio sources selected from the literature in order to determine the impact of the radio-jet in their circumnuclear environment. Our sample includes 58 Compact Steep Spectrum (CSS)…

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

We present radio and infrared observations of 4 hyper-compact HII regions and 4 ultra-compact HII regions in the southern Galactic plane. These objects were selected from a blind survey for UCHII regions using data from two new radio…

Astrophysics of Galaxies · Physics 2015-05-18 Tara Murphy , Martin Cohen , Ronald D. Ekers , Anne J. Green , Robin Wark , Vanessa Moss

Image-based searches have become a complementary approach for identifying pulsars, particularly at MHz frequencies where scattering and high dispersion measures affect high-time resolution observations. In this work, we searched the…

Astrophysics of Galaxies · Physics 2025-09-04 Silvia Mantovanini , N. Hurley-Walker , G. Anderson , K. Ross , S. W. Duchesne , T. J. Galvin

Using the Very Large Array (VLA) at 3.6~cm we identify four new compact radio sources in the vicinity of the cometary HII region G78.4+2.6 (VLA~1). The four compact radio sources (named VLA~2 to VLA~5), have near-infrared counterparts, as…

Astrophysics of Galaxies · Physics 2010-06-22 Citlali Neria , Yolanda Gomez , Luis F. Rodriguez

We report preliminary results of a visual inspection of ~4300 deg$^2$ covered by 4414 images of the 3-GHz VLA Sky Survey (VLASS, epoch 1.1) in search of extended radio structures. Over 7600 positions were registered, and for a subset of 270…

Astrophysics of Galaxies · Physics 2018-08-23 Agueda C. Villarreal Hernández , Heinz Andernach

We present first results from electronic Multi-Element Remotely Linked Interferometer Network (e-MERLIN) and electronic European VLBI Network (e-EVN) observations of a small sample of ultra-steep spectrum radio sources, defined as those…

Cosmology and Nongalactic Astrophysics · Physics 2013-02-14 Megan K. Argo , Zsolt Paragi , Huub Röttgering , Hans-Rainer Klöckner , George Miley , Mehreen Mahmud

From 1979--1996 the Green Bank Interferometer was used by the Naval Research Laboratory to monitor the flux density from 146 compact radio sources at frequencies near 2 and 8 GHz. We filter the ``light curves'' to separate intrinsic…

Astrophysics · Physics 2009-11-11 B. Rickett , T. J. W. Lazio , F. D. Ghigo

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

We present a catalog of 290 "winged" or X-shaped radio galaxies (XRGs) extracted from the latest (2014 December 17) data release of the "Very Large Array Faint Images of the Radio Sky at Twenty centimeter." We have combined these radio…

High Energy Astrophysical Phenomena · Physics 2020-07-23 Xiaolong Yang , Ravi Joshi , Gopal-Krishna , Tao An , Luis C. Ho , Paul J. Wiita , Xiang Liu , Jun Yang , Ran Wang , Xuebing Wu , Xiaofeng Yang

The polarisation properties of the intrinsically small (< 20 kpc) radio sources are briefly discussed. At centimetric and decimetric wavelengths, substantial polarised emission is often detected in quasars and, at a lower level, in radio…

Astrophysics · Physics 2007-05-23 D. Dallacasa

Extended radio emission detected around a sample of GHz Peaked Spectrum (GPS) radio sources is discussed. Evidence for extended emission which is related to the GPS source is found in 6 objects out of 33. Three objects are associated with…

Astrophysics · Physics 2009-11-11 C. Stanghellini , C. P. O'Dea , D. Dallacasa , P. Cassaro , S. A. Baum , R. Fanti , C. Fanti

In this work we address the problem of simultaneous multi-frequency detection of extragalactic point sources in maps of the Cosmic Microwave Background. We apply a new linear filtering technique, the so called `matched matrix filters', that…

Astrophysics · Physics 2009-11-13 D. Herranz , M. Lopez-Caniego , J. L. Sanz , J. Gonzalez-Nuevo

I will review some of the developments in studies of the host galaxy properties of Compact Steep Spectrum (CSS) and GigaHertz-Peaked Spectrum (GPS) radio sources. In contrast to previous reviews structured around observational technique, I…

Astrophysics · Physics 2009-11-13 J. Holt

Compiled radio spectra are presented for 208 extragalactic sources from the catalog created from the WMAP satellite all-sky survey data in a range of 23-94 GHz taken during the first year of its operation in orbit. 205 out of 208 WMAP…

Astrophysics · Physics 2007-05-23 Sergei A. Trushkin

Giant radio sources (GRSs) are the single largest astrophysical objects known in the universe that have grown to megaparsec scales ($\ge$ 0.7 Mpc). GRSs are much rarer compared with normal-sized radio galaxies. Still, the reason for the…

Astrophysics of Galaxies · Physics 2024-05-31 Netai Bhukta , Souvik Manik , Sabyasachi Pal , Sushanta K. Mondal

This is the third in a series of papers that present observations and results for a sample of 76 ultra-steep-spectrum radio sources designed to find galaxies at high redshift. Here we present multi-frequency radio observations, from the…

Astrophysics · Physics 2009-11-11 I. J. Klamer , R. D. Ekers , J. J. Bryant , R. W. Hunstead , E. M. Sadler , C. De Breuck