Related papers: The evolution of classical doubles: clues from com…
The radio structures and optical identifications of a sample of 242 sources classified as double-double radio sources by Proctor (2011) from a morphological study of sources in the FIRST (Faint Images of the Radio Sky at Twenty centimeters)…
The large number of differences between high- and low-redshift radio galaxies have almost all been discovered by looking at the bright 3C sample of radio sources. This has the disadvantage that the strong correlation between radio…
Radio galaxies can be seen out to very high redshifts, where in principle they can serve as probes of the early evolution of the Universe. Here we show that for any model of radio-galaxy evolution in which the luminosity decreases with time…
Beam power is a fundamental parameter that describes, in part, the state of a supermassive black hole system. Determining the beam powers of powerful classical double radio sources requires substantial observing time, so it would be useful…
We present an optical spectroscopic and imaging study of the environments of a complete sample of moderate-redshift, bent-double radio sources. More than half of the forty radio galaxies in the sample are associated with Abell richness…
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…
The majority of this paper is devoted to discrete radio sources, and their consequences for cosmology. Three main issues are considered: (i) what makes a galaxy radio loud?; (ii) what do we know about how the population of radio-loud…
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…
Distance duality relation (DDR) marks a fundamental difference between expanding and nonexpanding Universes, as an expanding metric causes angular diameter distance smaller than luminosity distance by an extra factor of $(1+z)$. Here we…
The results of an optical and infrared investigation of a radio sample drawn from the 1.4 GHz Leiden-Berkeley Deep Survey are presented. This is believed to be the most comprehensive sample of radio sources at millijansky flux limits that…
The Australia Telescope Large Area Survey (ATLAS), which is the widest deep field radio survey so far attempted, aims to probe the evolution of radio galaxies out to the edge of the Universe. Using AAOmega on the Anglo-Australian Telescope…
There is considerable evidence that powerful radio quasars and radio galaxies are orientation-dependent manifestations of the same parent population: massive spheroids containing correspondingly massive black holes. Following the…
Radio sources with steep and ultra-steep spectra, identified through a series of surveys of the Cold experiment using the RATAN-600 radio telescope, formed the basis of the Big Trio program aimed at discovering distant radio galaxies. With…
Multi-frequency radio observations of the radio bridge of a powerful classical double radio source can be used to determine: the beam power of the jets emanating from the AGN; the total time the source will actively produce jets that power…
The importance of studying old elliptical galaxies at redshift z ~ 1.5 is reviewed, considering both what can be learned by extending studies of the evolution of cluster galaxy scaling relations to earlier cosmic epochs, and the age-dating…
We compare two temporal properties of classical double radio sources: i) radiative lifetimes of synchrotron-emitting particles and ii) dynamical source ages. We discuss how these can be quite discrepant from one another, rendering use of…
Radio continuum surveys can detect galaxies over a very wide range in redshift, making them powerful tools for studying the distant universe. Until recently, though, identifying the optical counterparts of faint radio sources and measuring…
In our previous analysis we investigated the large-scale environment of two samples of radio galaxies (RGs) in the local Universe (i.e. with redshifts z<0.15), classified as FR I and FR II on the basis of their radio morphology. The…
We use three samples (3CRR, 6CE and 6C*) to investigate the radio luminosity function (RLF) for the `most powerful' low-frequency selected radio sources. We find that the data are well fitted by a model with a constant co-moving space…
In this paper we discuss the demographics of the radio blazar population: (i) what are their parent (`unbeamed') sources and (ii) what magnitude and/or type of evolution have they undergone ? The discussion is based on models of radio…