Related papers: Multi-frequency observations as a key to source an…
Several problems regarding the process of galaxy formation are still open. One of them is the role played by AGN phenomena in contributing to galaxy build-up and to Star Formation (SF) quenching. On the other hand, the theory of AGN…
We present 16 GHz (1.9 cm) deep radio continuum observations made with the Arcminute Microkelvin Imager (AMI) of a sample of low-mass young stars driving jets. We combine these new data with archival information from an extensive literature…
Radio-loud active galactic nuclei (RLAGN) play an important role in the evolution of galaxies through the effects on their environment. The two major morphological classes are core-bright (FRI) and edge-bright (FRII) sources. With the…
The goal of this work is to determine the nature of the relation between morphology and accretion mode in radio galaxies, including environmental parameters. The CoNFIG extended catalogue (improved by new Ks-band identifications and…
We study the jet and counterjet of the powerful classical double FRII radio galaxy Cygnus A as seen in the 5, 8 and 15-GHz radio bands using the highest spatial resolution and signal-to-noise archival data available. We demonstrate that the…
We present the first large sample investigation of the properties of jets in Fanaroff and Riley type I radio galaxies (FR-I) based on data from the Chandra archive. We explore relations between the properties of the jets and the properties…
Relativistic jets of radio loud active galactic nuclei (AGN) produce highly directed, intense beams of radiation. A fraction of this beamed radiation scatters on the thermal plasma generally surrounding an AGN. The morphology of the…
The past 20 years have seen phenomenal progress in our understanding of BL Lac objects. They form part of the blazar class, which are radio-loud AGN whose relativistic jets are aligned along our line of sight. Several critical milestones…
The spectra of Active Galactic Nuclei (AGNs) are often characterized by a wealth of emission lines with different profiles and intensity ratios that led to a complicated classification. Their electro-magnetic radiation spans more than 10…
Radio relic sources in galaxy clusters are often described as the remnants of powerful radio galaxies. Here we develop a model for the evolution of such relics after the jets cease to supply energy to the lobes. This includes the treatment…
Fourier power spectra and phases of a signal from a large number of radiating sources orbiting around a black hole are investigated. It is assumed that the individual sources (bright spots) are located in an accretion disc and their…
Ultra-deep radio surveys are an invaluable probe of dust-obscured star formation, but require a clear understanding of the relative contribution from radio AGN to be used to their fullest potential. We study the composition of the $\mu$Jy…
We present mid-IR interferometric observations of 6 type 1 AGNs at multiple baseline lengths of 27--130m, reaching high angular resolutions up to lambda/B~0.02 arcseconds. For two of the targets, we have simultaneous near-IR interferometric…
We have compared the radio emission from a sample of parsec-scale AGN jets as measured by the VLBA at 15 GHz, with their associated gamma-ray properties that are reported in the Fermi LAT 3-month bright source list. We find in our…
I define 3 samples of extragalactic radio sources of type FRII, containing 26 objects in total. The control sample consists of 6C and 7C sources with radio-luminosities of around 10E27 W\Hz at 151 MHz and z~1. The other samples contain 3CRR…
I discuss the nature of `hotspots' and `jet knots' in the kpc-scale structures of powerful radio galaxies and their relationship to jet-environment interactions. I describe evidence for interaction between the jets of FRI sources and their…
The nature of X-shaped sources is a matter of considerable debate: it has even been proposed that they provide evidence for black hole mergers$ / $spin reorientation, and therefore constrain the rate of strong gravitational wave events…
Luminous infrared galaxies are systems enshrouded in dust, which absorbs most of their optical/UV emission and re-radiates it in the mid- and far-infrared. Radio observations are largely unaffected by dust obscuration, enabling us to study…
Knowing the site of gamma-ray emission in AGN jets will do much for our understanding of the physics of the source. In particular, if the emission region is close to the black hole then absorption of gamma-rays with photons from the…
The LOw Frequency ARray Two-metre Sky Survey second data release (LoTSS DR2) covers 27\% of the northern sky and contains around four million radio sources. The development of this catalogue involved a large citizen science project (Radio…