Related papers: The most distant radio quasars at the highest reso…
We match quasars discovered in a multi-color survey centered on the northern Hubble Deep Field (HDF) with radio sources from an ultra-deep radio survey. Although 3 out of 12 quasars are detected at a level below 0.2 mJy at 1.4 GHz, all of…
We present details of a new sample of radio-loud quasars drawn from 0.013 sr of the 7C Redshift Survey. This sample is small (21 quasars) but complete in that every object with an unresolved nucleus and/or broad emission lines with…
The radio properties of 11 obscured `radio-intermediate' quasars at redshifts z>~2 have been investigated using the European Very-Long-Baseline-Interferometry Network (EVN) at 1.66 GHz. A sensitivity of ~25 micro Jy per 14x17 mas2 beam was…
From examination of only 4 deg^2 of sky in the NOAO Deep Wide-Field Survey (NDWFS) region, we have identified the first radio-loud quasar at a redshift z>6. The object, FIRST J1427385+331241, was discovered by matching the FLAMEX IR survey…
Radio-loud high-redshift quasars (HRQs), although only a few of them are known to date, are crucial for the studies of the growth of supermassive black holes (SMBHs) and the evolution of active galactic nuclei (AGN) at early cosmological…
We report the discovery of X-ray emission from CFHQS J142952+544717, the most distant known radio-loud quasar at z=6.18, on Dec. 10--11, 2019 with the eROSITA telescope on board the SRG satellite during its ongoing all-sky survey. The…
Few high-redshift, radio-loud quasars are known to date. The extremely luminous, radio-bright quasar, SDSS J013127.34-032100.1 was recently discovered at a redshift of $z=5.18$. We observed the source with high resolution very long baseline…
High-redshift quasars are currently the only probes of the growth of supermassive black holes and potential tracers of structure evolution at early cosmic time. Here we present our candidate selection criteria from the Panoramic Survey…
High-redshift radio galaxies (HzRGs) are some of the rarest objects in the Universe. They are often found to be the most massive galaxies observed at any epoch and are known to harbour active supermassive black holes that give rise to…
We explore the radio properties of powerful (rest-frame luminosity $\gtrsim10^{28}$ W Hz$^{-1}$ at 500 MHz) high-redshift (z > 3.5) quasars. The aim of this study is to gain a better understanding of radio-loud sources at the epoch when…
The interactions between radio jets and the interstellar medium play a defining role for the co-evolution of central supermassive black holes and their host galaxies, but observational constraints on these feedback processes are still very…
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 888 MHz radio detection in the Rapid ASKAP Continuum Survey (RACS) of VIK J2318$-$3113, a $z$=6.44 quasar. Its radio luminosity (1.2 $\times 10^{26}$ W Hz$^{-1}$ at 5 GHz) compared to the optical luminosity (1.8 $\times…
The most luminous quasars at high redshift harbour the fastest-growing and most massive black holes in the early Universe. They are exceedingly rare and hard to find. Here, we present our search for the most luminous quasars in the redshift…
Distant quasars are unique tracers to study the formation of the earliest supermassive black holes (SMBHs) and the history of cosmic reionization. Despite extensive efforts, only two quasars have been found at $z\ge7.5$, due to a…
We present near-infrared spectra of seven radio-loud quasars with a median redshift of 2.1, five of which were previously known to have Ly alpha nebulae. Extended [OIII]5007 and H alpha emission are evident around six objects, at the level…
The radio-loud quasar SDSS J114657.79+403708.6 at a redshift z=5.0 is one of the most distant radio-loud objects. The IR-optical luminosity and spectrum suggest that its black hole has a very large mass: M=(5+-1)x 1e9 Msun. The…
We report on two programs to address differential evolution between the radio-loud and radio-quiet quasar populations at high (z>4) redshift. Both programs entail studying the radio properties of optically-selected quasars. First, we have…
We present results from two surveys for radio-loud quasars. These are (1) a northern survey reaching S(5GHz)=0.2Jy and (2) the Parkes QSO survey reaching S(2.7GHz)=0.25Jy, which together cover most of the sky. Both surveys use digitised…
The powerful high-redshift quasar J2102+6015 (at z=4.575) may provide useful information for studying supermassive black hole growth, galaxy evolution and feedback in the early Universe. The source has so far been imaged with very long…