Related papers: Multi-frequency Analysis of the two CSS quasars 3C…

We examine lengthy radio light curves of the flat spectrum radio galaxy 3C 454.3 for possible quasi-periodic oscillations (QPOs). The data used in this work were collected at five radio frequencies, 4.8, 8.0, 14.5, 22.0, and 37.0 GHz…

We present MERLIN observations of Galactic 21-cm HI absorption at an angular resolution of c. 0.1-0.2 arcsec and a velocity resolution of 0.5 km/s, in the direction of three moderately low latitude (-8< b <-12 deg) extragalactic radio…

A statistical study is presented of (a) the frequency of narrow CIV lambda 1549 absorption lines in 1.5 <~ z <~ 3.6 radio-quiet and radio-loud quasars, and of (b) the UV and radio properties of the absorbed quasars. The quasar sample is…

We report on the very first radio detection associated with the peculiar hourglass-morphology X-rays surrounding 3C 294 at z=1.8. Using International Low Frequency Array (LOFAR) data at 144 MHz and Chandra data at 0.3-6 keV, we find that…

Winged, or X-shaped, radio sources form a small class of morphologically peculiar extragalactic sources. We present multi-frequency radio observations of two such sources. We derive maximum ages since any re-injection of fresh particles of…

Red quasi-stellar objects (QSOs) are a subset of the quasar population with colours consistent with reddening due to intervening dust. Recent work has demonstrated that red QSOs show special radio properties that fundamentally distinguish…

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…

The highest-redshift quasars are still rare and valuable objects for observational astrophysics and cosmology. They provide important constraints on the growth of the earliest supermassive black holes in the Universe, and information on the…

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 aim of this paper is to present an analysis of newly acquired X-ray observations of 16 extragalactic radio sources, listed in the Third Cambridge Revised (3CR) catalog, and not previously observed by Chandra. Observations were performed…

We present 6 GHz e-MERLIN observations of 42 $z<0.2$ type 1 and type 2 mostly radio-quiet quasars ($L_{\rm[OIII]}\gtrsim10^{42}$ erg s$^{-1}$; $L_{\rm AGN}\gtrsim10^{45}$ erg s$^{-1}$) from the Quasar Feedback Survey. The nature and origin…

We have used narrow emission line data from the new 7C Redshift Survey to investigate correlations between the narrow-line luminosities and the radio properties of radio galaxies and steep-spectrum quasars. The 7C Redshift Survey is a…

We are entering a new era of sensitive, large-area and multi-frequency radio surveys that will allow us to identify Gigahertz-Peaked Spectrum (GPS) and Compact Steep Spectrum (CSS) radio sources over a wide range in radio luminosity and…

We report on 1.7 and 5.0 GHz observations of the z=3.087 radio galaxy B3 J2330+3927, using the Very Long Baseline Array (VLBA), and archival 1.4 and 8.4 GHz Very Large Array (VLA) data. Our VLBA data identify a compact, flat spectrum…

As part of an on-going radio supernova monitoring program, we have discovered a variable, compact steep spectrum radio source ~65 arcsec (~4 kpc) from the centre of the starburst galaxy NGC 3310. If the source is at the distance of NGC…

This Research Note follows up a Letter in which I posit that J1211+743 is a restarted radio source. This means that its structure, where the jet points to the relic lobe, is only apparently paradoxical. Here, I propose the same scenario and…

Context. Radio-loud AGNs with powerful relativistic jets are thought to be associated with rapidly spinning black holes (BHs). BH spin-up may result from a number of processes, including accretion of matter onto the BH itself, and…

Radio sources with steep spectra are preferentially associated with the most distant galaxies, the $\alpha-z$ relation, but the reason for this relation is an open question. The spatial distribution of spectra in high-z radio sources can be…

The flat spectrum radio quasar 1633+382 (4C~38.41) showed a significant increase of its radio flux density during the period 2012 March - 2015 August which correlates with gamma-ray flaring activity. Multi-frequency simultaneous VLBI…

We report on the second round of Chandra observations of the 3C snapshot survey developed to observe the complete sample of 3C radio sources with z<0.3 for 8 ksec each. In the first paper, we illustrated the basic data reduction and…