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We present the first results from the Distant Radio Galaxies Optically Non-detected in the SDSS (DRaGONS) Survey. Using a novel selection technique for identifying high redshift radio galaxy (HzRG) candidates, a large sample of bright…

Astrophysics · Physics 2008-11-26 S. J. Schmidt , A. J. Connolly , A. M. Hopkins

We present deep near-infrared $K_{\rm s}$-band imaging for 35 of the 53 sources from the high-redshift ($z > 2$) radio galaxy candidate sample defined in Broderick et al. (2022). These images were obtained using the High-Acuity Widefield…

In a pilot search for high-redshift radio QSOs, we have obtained spectra of 55 FIRST sources (S(1.4GHz) > 1 mJy) with very red (O-E > 3) starlike optical identifications. 10 of the candidates are QSOs with redshifts 3.6 < z < 4.4 (4…

Astrophysics · Physics 2009-11-07 C. R. Benn , M. Vigotti , M. Pedani , J. Holt , K. -H. Mack , R. Curran , S. F. Sanchez

We present optical and/or near-IR images of 128 ultra steep spectrum (USS) radio sources. Roughly half of the objects are identified in the optical images (R <~ 24), while in the near-IR images, >94% are detected at K<~ 22. The mean…

We have compiled a sample of 234 ultra-steep-spectrum(USS)-selected radio sources in order to find high-redshift radio galaxies (HzRGs). The sample is in the southern sky at -40 deg < DEC < -30 deg which is the overlap region of the 408-MHz…

Cosmology and Nongalactic Astrophysics · Physics 2009-11-13 J. J. Bryant , H. M. Johnston , J. W. Broderick , R. W. Hunstead , C. De Breuck , B. M. Gaensler

We obtained spectra of 60 red, starlike objects (E< 18.8) identified with FIRST radio sources, S_{1.4GHz} > 1 mJy. Eight are QSOs with redshift z> 3.6.Combined with our pilot search (Benn et al 2002), our sample of 121 candidates yields a…

We have started a search for High Redshift Radio Galaxies (HZRGs) in an area covering 7 sr by selecting a sample of Ultra Steep Spectrum (USS) sources with a low flux density cut-off S(1400 MHz) > 10 mJy and a steep spectral index cut-off…

Astrophysics · Physics 2016-01-27 Carlos De Breuck , Wil van Breugel , Huub Rottgering , George Miley

Study of high-redshift radio galaxies (HzRGs) can shed light on the active galactic nuclei (AGNs) evolution in massive elliptical galaxies. The vast majority of observed high-redshift AGNs are quasars, and there are very few radio galaxies…

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…

We report a discovery of proto-cluster candidates around high redshift radio galaxies at z~2.5 on the basis of clear statistical excess of colour-selected galaxies around them seen in the deep near-infrared imaging data obtained with CISCO…

Astrophysics · Physics 2009-11-11 Masaru Kajisawa , Tadayuki Kodama , Ichi Tanaka , Toru Yamada , Richard Bower

We have compiled a sample of 234 ultra-steep-spectrum (USS) selected radio sources in order to find high-redshift radio galaxies. The sample covers the declination range -40deg < DEC < -30deg in the overlap region between the 1400-MHz NRAO…

Cosmology and Nongalactic Astrophysics · Physics 2009-11-13 J. J. Bryant , J. W. Broderick , H. M. Johnston , R. W. Hunstead , B. M. Gaensler , C. De Breuck

Perhaps as many as 10% of high redshift radio galaxy (HzRG; z > 2) candidates that are selected using an Ultra Steep radio Spectrum (USS) criterion fail to show optical emission (continuum, lines) in deep Keck exposures. Their parent…

This is the second in a series of papers presenting observations and results for a sample of 76 ultra-steep-spectrum (USS) radio sources in the southern hemisphere designed to find galaxies at high redshift. Here we focus on the optical…

We present high spatial resolution near-infrared H-band (1.65 microns) images, taken with ISAAC on UT1 of ESO VLT, of three radio-loud quasars at z = 1.5, as a pilot study for imaging of a larger sample of radio-loud and radio-quiet quasars…

Astrophysics · Physics 2009-10-31 Renato Falomo , Jari Kotilainen , Aldo Treves

Giant radio galaxies (GRGs) are radio galaxies that have projected linear extents of more than 700 kpc or 1 Mpc, depending on definition. We have carried out a careful visual inspection in search of GRGs of the Bootes LOFAR Deep Field…

Astrophysics of Galaxies · Physics 2022-09-14 Marco Simonte , Heinz Andernach , Marcus Brüggen , Dominik Schwarz , Isabella Prandoni , Anthony G. Willis

We investigate the nature of the faintest radio sources detected in 3 VLA surveys, to faint limits 8 microJy at 8.5 GHz. Using the Keck Low Resolution Imaging Spectrograph in BRI and the Near Infra Red Camera in K, we image 51 radio…

Astrophysics · Physics 2009-11-07 Nathan Roche , James Lowenthal , David Koo

Ultra-steep spectrum (USS) radio sources are good tracers of powerful radio galaxies at $z > 2$. Identification of even a single bright radio galaxy at $z > 6$ can be used to detect redshifted 21cm absorption due to neutral hydrogen in the…

Astrophysics of Galaxies · Physics 2018-01-31 A. Saxena , P. Jagannathan , H. J. A. Röttgering , P. N. Best , H. T. Intema , M. Zhang , K. J. Duncan , C. L. Carilli , G. K. Miley

High redshift radio galaxies are amongst the most massive galaxies in the early Universe and have properties expected from central galaxies in forming clusters. We are carrying out an observational programme on the VLT to find and study…

Astrophysics · Physics 2007-05-23 J. D. Kurk , B. P. Venemans , H. J. A. Roettgering , G. K. Miley , L. Pentericci

We constructed and presented in the first paper of this series a new sample of 84 large angular size radio galaxies by selecting from the NRAO VLA Sky Survey objects with angular size > 4', declination above +60 degrees and total flux…

Astrophysics · Physics 2009-11-07 L. Lara , I. Marquez , W. D. Cotton , L. Feretti , G. Giovannini , J. M. Marcaide , T. Venturi

We use the 6C** sample to investigate the co-moving space density of powerful, steep-spectrum radio sources. This sample, consisting of 68 objects, has virtually complete K-band photometry and spectroscopic redshifts for 32 per cent of the…

Astrophysics · Physics 2008-11-26 Maria J. Cruz , Matt J. Jarvis , Steve Rawlings , Katherine M. Blundell
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