相关论文: Are 3C249.1 and 3C334 restarted quasars?

PBC J2333.9-2343 is a giant radio galaxy which shows different characteristics at different wavebands that are difficult to explain within the actual generic schemes of unification of active galactic nuclei (AGN), thus being a good…

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…

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…

Giant double-lobed radio source 4C34.47 displays a straight one-sided jet, measuring a record length of 380kpc, in its double-lobed radio structure. Assuming an intrinsically symmetric two-sided jet structure the radio source jet axis must…

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…

A Chandra observation of the radio-loud quasar 3C9 at redshift z=2.012 has revealed extended X-ray emission coincident with the radio jet. Of particular interest is the appearance of both jet and counterjet, which argues against the X-ray…

The archetypical, nearby (z=0.37) quasar 3C 48 is an unusual CSS radio source with excess far-IR emission, whose one-sided radio jet is aligned with the extended ionized emission and a putative second nucleus. Because of its high AGN…

Models of radio galaxy physics have been primarily based on high frequency ($\geqslant$1 GHz) observations of their jets, hotspots, and lobes. Without highly resolved low frequency observations, which provide information on older plasma,…

We present the discovery of a large extended radio jet associated with the extremely radio-loud quasar J1601+3102 at $z\sim5$ from sub-arcsecond resolution imaging at 144 MHz with the LOFAR International Telescope. These large radio lobes…

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…

Analysis of Giant Metrewave Radio Telescope low frequency data for an X-shaped source, 3C 223.1 has revealed an unusual result as discussed earlier by Lal & Rao (2004, MNRAS in press). The radio morphologies of it at 240 and 610 MHz show a…

During the period 1966.5 - 2006.2 the 15GHz and 8GHz lightcurves of 3C454.3 (z=0.859) show a qsasi-periodicity of ~12.8 yr (~6.9 yr in the rest frame of the source) with a double-bump structure. This periodic behaviour is interpreted in…

We present multi-frequency observational results for the Compact Steep-Spectrum (CSS) quasar 3C309.1. The observations were carried out with the VSOP at 1.6 and 4.8GHz and the VLBA at 15.4GHz. The source has a distorted, one-sided radio…

Radio relics are diffuse radio sources observed in galaxy clusters, probably produced by shock acceleration during cluster-cluster mergers. Their large size, of the order of 1 Mpc, indicates that the emitting electrons need to be…

We present observations at 1.7 and 8.4 GHz of two Compact Steep Spectrum (CSS) sources from a complete sample of low-intermediate power radio galaxies. 3C346 shows an asymmetric structure with a one-sided ``jet'' and ``hot spot''. Present…

NGC 613 (AM 0132-294) is a multi armed spiral with an active nucleus. Radio emission is aligned along the narrow inner bar of the spiral and appears to include inner and outer pairs of radio sources which define a line of ejection from this…

In this paper, we test the possibility that the structure of the largest radio galaxy J1420-0545 may have been formed by restarted rather than primary jet activity. This hypothesis was motivated by the unusual morphological properties of…

We present a study of sub-pc scale radio structure of the radio galaxy 3C 84/NGC 1275 based on the Very Long Baseline Array (VLBA) data at 43 GHz. We discover a limb-brightening in the "restarted" jet associated with the 2005 radio…

We present results of deep 150 MHz observations with the GMRT which show several extended radio sources with a range of morphologies. These sources have then further followed up at higher frequencies (610 and 1400 MHz) with the GMRT. GMRT…

We present a new wide-field map of the radio galaxy 3C 129 and its companion galaxy 3C 129.1 at lambda=90 cm. We see a distinct steep-spectrum feature near the head of 3C 129, extending in a direction perpendicular to the radio tails. We…