Related papers: The Detection of Diffuse Extended Structure in 3C~…
We present time-resolved broad-band observations of the quasar 3C 279 obtained from multi-wavelength campaigns conducted during the first two years of the Fermi Gamma-ray Space Telescope mission. While investigating the previously reported…
We present an analysis of the energetics and particle content of the lobes of 24 radio galaxies at the cores of cooling clusters. The radio lobes in these systems have created visible cavities in the surrounding hot, X-ray-emitting gas,…
We investigate the radio emitting structures of radio-quiet active galactic nuclei with an emphasis on radio-quiet quasars to study their connection to Seyfert galaxies. We present and analyse high-sensitivity VLA radio continuum images of…
We present the discovery of the radio-loud quasar PSO J352.4034-15.3373 at z=5.84 pm 0.02. This quasar is the radio brightest source known, by an order of magnitude, at z~6 with a flux density in the range of 8-100 mJy from 3GHz to 230MHz…
The quasar 3C 286, a well-known calibrator source in radio astronomy, was found to exhibit exceptional multiwavelength properties. Its rich and complex optical emission-line spectrum revealed its narrow-line Seyfert 1 (NLS1) nature. Given…
Low-frequency radio observations of galaxy clusters are the key to detecting the diffuse extended emission associated with them. The presence and properties of such radio sources in galaxy clusters reveal the existence of magnetic fields on…
We report the results of a 15 GHz (2 cm) multi-epoch VLBA program, begun in 1994 to study the outflow in radio jets ejected from quasars and active galaxies. The observed flow of 208 distinct features measured in 110 quasars, active…
Lobe-dominated radio-loud (LD RL) quasars occupy a restricted domain in the 4D Eigenvector 1 (4DE1) parameter space which implies restricted geometry/physics/kinematics for this subclass compared to the radio-quiet (RQ) majority of quasars.…
Clues to the physical conditions in radio cores of blazars come from measurements of brightness temperatures as well as effects produced by intrinsic opacity. We study the properties of the ultra compact blazar AO 0235+164 with RadioAstron…
Inverse Compton cooling limits the brightness temperature of the radiating plasma to a maximum of $10^{11.5}$ K. Relativistic boosting can increase its observed value, but apparent brightness temperatures much in excess of $10^{13}$ K are…
The large scale jet of quasar 3C 273 has been observed in radio to $\gamma$ ray frequencies. Earlier the X-ray emission from knot A of this jet has been explained with inverse Compton scattering of the cosmic microwave background radiations…
We present Giant Metrewave Radio Telescope (GMRT) 323 MHz radio continuum observations toward 13 radio-loud quasars at $z>5$, sampling the low-frequency synchrotron emission from these objects. Among the 12 targets successfully observed, we…
We report initial results from the detection of optical emission in the arcsecond-scale radio jets of two quasars utilizing images from the {\it Hubble Space Telescope} archive. The optical emission has a very knotty appearance and is…
We present new 144-MHz LOFAR observations of the prototypical `X-shaped' radio galaxy NGC 326, which show that the formerly known wings of the radio lobes extend smoothly into a large-scale, complex radio structure. We argue that this…
Up to now, jet kinematic studies of radio quasars have barely reached beyond the redshift range at $z>3.5$. This significantly limits our knowledge of high-redshift jets, which can provide key information for understanding the jet nature…
The radio source J0028+0035 is a recently discovered double--double radio galaxy at redshift z=0.398. Its relic outer lobes are separated by about 3' in the sky, corresponding to ~1 Mpc projected linear size. Inside this large-scale…
Using long slit emission-line spectra we detect a fast outflow of ionized gas, with velocities up to 1000 km/s, in the nearby powerful radio galaxy 3C 293 (z = 0.045). The fast outflow is located about 1 kpc east of the nucleus, in a region…
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…
We present new results on the parsec-scale jet of the quasar 3C395, derived from VLBI polarization sensitive observations made in 1995.91 and 1998.50 at 8.4, 15.4 and 22.2 GHz. The observations show a complex one-sided jet extending up to…
I bring together evidence for the rapidity with which quasars' radio synchrotron lobe emission fades and for the intermittency with which jet plasma is ejected from individual quasars and radio galaxies and affirm the picture presented by…