Related papers: Radio-quiet objects in the 2QZ survey
We present spectra for a sample of radio sources from the FIRST survey, and use them to define the form of the redshift distribution of radio sources at mJy levels.We targeted 365 sources and obtained 46 redshifts (13 per cent of the…
We analyze the Parkes quarter-Jansky flat-spectrum sample of QSOs in terms of space density, including the redshift distribution, the radio luminosity function, and the evidence for a redshift cutoff. With regard to the luminosity function,…
We present the first eight months of data from our secondary target program within the ongoing Dark Energy Spectroscopic Instrument (DESI) survey. Our program uses a mid-infrared and optical colour selection to preferentially target…
We have performed quasi-simultaneous radio flux density measurements at 2.7 and 10 GHz for all PG quasars with radio flux densities between 4-200 mJy. We find that a large fraction of these sources are variable, flat-spectrum quasars. This…
We use Southern African Large Telescope (SALT) to perform long-slit spectroscopic observations of 23 newly discovered radio-loud quasars (RLQs) at $2.7<z<3.3$. The sample consists of powerful AGN brighter than 200 mJy at 1.4 GHz and is…
We report the results of 20, 6, and 2 cm VLA and 1.5 cm OVRO observations of the optically-selected CfA Seyfert galaxies and the bolometric-flux-limited 12-Micron active galaxy sample. Every object observed was detected at 6 cm. Only 6-8%…
Based on an R-band imaging survey of 6 high redshift (z~2) and high luminosity (M<-28mag) QSOs, we report the detection of extensions in two radio-quiet and one radio-loud QSO. The extensions are most likely due to the host galaxies of…
In this paper we present results of an analysis of radio-quiet QSO environments. The aim is to determine the relation between QSOs and galaxies as a function of redshift. We cross-correlate a sample of ~150 QSOs from optically and X-ray…
We present spectroscopic and eleven-band photometric redshifts for galaxies in the 100-uJy Subaru/XMM-Newton Deep Field radio source sample. We find good agreement between our redshift distribution and that predicted by the SKA Simulated…
We have obtained H-band spectra of 32 luminous quasars at 2.0<z<2.5 with the Multiple Mirror Telescope. The sample contains 15 radio-loud quasars (RLQs) and 17 radio-quiet quasars (RQQs). We have measured emission line properties from the…
In this paper we present the results of an optical and near infrared identification of 514 radio sources from the FIRST survey (Faint Images of the Radio Sky Survey at Twenty centimeters) with a flux-density limit of 1 mJy in the NOAO…
We revisit the proximity effect produced by QSOs at redshifts 2.1-3.3 applying the FLO approach (Saitta et al. 2008) to a sample of ~6300 Ly-alpha lines fitted in 21 high resolution, high signal-to-noise spectra. This new technique allows…
With the goal of investigating the nature and the environment of the faint radio sources (at mJy level), here are presented results of X-ray dentifications of Faint Imaging Radio Survey at Twenty centimetres (FIRST) in the 9 square degrees…
Aims: In this work the luminosity function of QSOs is measured in the redshift range 3.5<z<5.2 for the absolute magnitude interval -21<M_{145}<-28. The determination of the faint end of the luminosity function at these redshifts provides…
We present a power spectrum analysis of the final 2dF QSO Redshift Survey catalogue containing 22652 QSOs. Utilising the huge volume probed by the QSOs, we can accurately measure power out to scales of ~500Mpc and derive new constraints, at…
Recent studies have found a striking positive correlation between the amount of dust obscuration and enhanced radio emission in quasi-stellar objects (QSOs). However, what causes this connection remains unclear. In this paper we analyse…
We explore the X-ray properties of optically selected QSOs spectroscopically identified in the course of the 2dF QSO survey (2QZ). Our main goal is to expand to higher redshifts previous findings suggesting the presence of a fraction of…
We present progress results of a new survey for bright QSOs (V<14.5, R<15.4, B_J<15.2) covering the whole sky at |b|>30. The surface density of QSOs brighter than B_J=14.8 turns out to be $2.9 \pm 0.8 \cdot 10^{-3} deg^{-2}$. The optical…
Optically luminous quasars at $z > 5$ are important probes of super-massive black hole (SMBH) formation. With new and future radio facilities, the discovery of the brightest low-frequency radio sources in this epoch would be an important…
Using the most recent (1998) version of the VLA FIRST survey radio catalog, we have searched for radio emission from 1704 quasars taken from the most recent (1993) version of the Hewitt and Burbidge quasar catalog. These quasars lie in the…