scholarly journals 1245+676 — A CSO/GPS Source being an Extreme Case of a Double-Double Structure

2003 ◽  
Vol 20 (1) ◽  
pp. 16-18 ◽  
Author(s):  
Andrzej Marecki ◽  
Peter D. Barthel ◽  
Antonis Polatidis ◽  
Izabela Owsianik
Keyword(s):  
Radio Galaxy ◽  
Extreme Case ◽  
Double Object ◽  
Radio Structure ◽  
Double Structure ◽  
The Core ◽  
Vlbi Observations ◽  
New Phase

AbstractAGN with the so-called 'double-double' radio structure have been interpreted as restarted AGN where the inner structure is a manifestation of a new phase of activity which happened to begin before the outer radio lobes resulting from the previous one had faded completely. The radio galaxy 1245+676 is an extreme example of such a double-double object — its outer structure, measuring 970 h−1 kpc, is five orders of magnitude larger than the 9.6 h−1 pc inner one. We present a series of VLBI observations of the core of 1245+676 which appears to be a compact symmetric object (CSO). We have detected the motion of the CSOs lobes, measured its velocity, and inferred the kinematic age of that structure.

scholarly journals Relativistic Jets in Low Power Radio Galaxies

1998 ◽  
Vol 164 ◽  
pp. 85-86 ◽  
Author(s):  
G. Giovannini ◽  
E. Arbizzani ◽  
L. Feretti ◽  
T. Venturi ◽  
W.D. Cotton ◽  
...  
Keyword(s):  
Low Power ◽  
Radio Galaxy ◽  
Morphological Changes ◽  
Radio Galaxies ◽  
Relativistic Jets ◽  
Radio Structure ◽  
The Core ◽  
Vlbi Observations ◽  
Relativistic Jet ◽  
Superluminal Motion

AbstractFrom VLBI observations of 11 FR I radio galaxies we find that: 1. parsec scale jets are relativistic; 2. 3C 264 shows a relativistic jet decelerating moving from the core to the extended lobes; 3. 3C 338 is a source with asymmetric parsec scale structure and morphological changes, implying proper motion on both sides of the source; 4. 1144+35 is an extended low power radio galaxy with an apparent superluminal motion in its parsec scale radio structure.

scholarly journals High Resolution Observations of the Quasar 3C147

1982 ◽  
Vol 97 ◽  
pp. 289-290 ◽  
Author(s):  
E. Preuss ◽  
W. Alef ◽  
I. Pauliny-Toth ◽  
K. I. Kellermann
Keyword(s):  
High Resolution ◽  
Opposite Direction ◽  
Surface Brightness ◽  
Lower Surface ◽  
Phase Information ◽  
Double Structure ◽  
The Core ◽  
Vlbi Observations ◽  
The Usa ◽  
Size Scales

We report here preliminary results of observations of the quasar 3C147 which were made at 6 cm with a resolution of about 1 milliarcsecond using a VLB interferometer system with four antennas in the USA and one in Europe. Our observations are shown in Figure 1 along with previously published maps on larger size scales. VLA observations made at 2 cm wavelength (Fig. 1a) show an extended feature lying about 0.5 arc-seconds (3.5 kpc) to the northeast of a bright core (Readhead et al. 1980), while VLBI observations made at 18, 50, and 91 cm (Readhead and Wilkinson 1980, Wilkinson et al. 1977, and Simon et al. 1980) show a jet-like feature extending about 0.2 arcsec (1 kpc) in the opposite direction (Fig. 1b). The 18 cm VLB observations also indicated the presence of a smaller elongated feature extending only 3 milliarcseconds (20 pc) again toward the northeast (Fig. 1c). We have observed 3C147 in March 1978 and again in April 1981 with a resolution of 0.7 and 1.5 milliarcsec respectively. The 1981 data (Fig. 1d) clearly show the double structure of the core as well as a lower surface brightness feature which can also be seen in the 18 cm map. Our 1978 data (Fig. 1e) has better resolution and shows considerable structure in the milliarcsec component, but due to the absence of phase information in these data, the details are not reliable and the orientation is uncertain by 180°. The orientation is, however, specified by reference to the 1981 data.

scholarly journals The Extraordinary Radio Galaxy MRC B1221–423

2003 ◽  
Vol 20 (1) ◽  
pp. 1-5 ◽  
Author(s):  
V. Safouris ◽  
R. W. Hunstead ◽  
O. R. Prouton
Keyword(s):  
Radio Source ◽  
Radio Galaxy ◽  
Early Stage ◽  
Elliptical Galaxy ◽  
Empirical Relationship ◽  
Host Galaxy ◽  
Narrow Line ◽  
Powerful Radio ◽  
Double Structure ◽  
The Core

AbstractMRC B1221–423 is a compact steep spectrum (CSS) radio source in the core of a remarkable elliptical galaxy. We examine its environment with long-slit spectra and multicolour images. A high-resolution synthesis image shows the radio source to have a 1″.5 (5.7 kpc) double structure. We use the empirical relationship between jet kinetic power and narrow line luminosity to infer a source age of ˜105 yr. The z = 0.1706 host galaxy is clearly disturbed, with tidal features and shells providing plausible evidence for a merger with one or more close companions. This evidence leads us to conclude that B1221–423 may be the progenitor of a much larger source, caught at an early stage in its radio evolution. We speculate that it is the interaction and accompanying events which have triggered this young powerful radio source.

scholarly journals Multi-Frequency VLBI observations of 3C390.3

1996 ◽  
Vol 175 ◽  
pp. 35-37 ◽  
Author(s):  
E. Preuss ◽  
W. Alef ◽  
K. I. Kellermann
Keyword(s):  
High Resolution ◽  
Radio Galaxy ◽  
The Other ◽  
Broad Line ◽  
Bright Region ◽  
The Core ◽  
Vlbi Observations ◽  
Distinct Features

We have mapped the broad line radio galaxy 3C390.3 at 1.3, 6, and 18 cm wavelengths with resolutions ranging from 0.2 to 2.7 mas. Our new 6 cm image is consistent with a stationary bright region located 4 to 5 mas from the core and motion of the other features with apparent velocities of 0.4 to 0.7 mas/yr. Our high resolution 1.3 cm image indicates that the ‘jet’ breaks up into 5 or more distinct features.

scholarly journals VLBI Observations of the Superluminal Sources 3C 273 and 3C 279

1984 ◽  
Vol 110 ◽  
pp. 105-107 ◽  
Author(s):  
S. C. Unwin ◽  
J. A. Biretta
Keyword(s):  
Radio Structure ◽  
The Core ◽  
Vlbi Observations ◽  
Superluminal Motion ◽  
Superluminal Expansion

Monitoring of the radio structure in the core of 3C 273 has yielded a series of hybrid maps in which substantial source evolution can be seen. We discuss the superluminal motion of components in the jet of 3C 273, and the evolution of their flux densities and spectra. For 3C 279 we identify a new epoch of superluminal expansion with v/c = 6.5.

scholarly journals VLBI Observations of the Radio Jet in 3C 273

1988 ◽  
Vol 129 ◽  
pp. 27-28
Author(s):  
S. C. Unwin ◽  
R. J. Davis
Keyword(s):  
Dynamic Range ◽  
Large Range ◽  
High Dynamic Range ◽  
No Emission ◽  
The Core ◽  
Vlbi Observations ◽  
High Dynamic ◽  
Quasar 3C 273

We present a new high dynamic range map of the quasar 3C 273, made from observations with a VLBI network of 12 telescopes. This new map at 18 cm wavelength has one of the highest dynamic ranges yet achieved with VLBI, and it shows the ‘jet’ extending to at least 180 milliarcsec, or 330 pc from the nucleus of the quasar. Strong limits can be placed on the brightness of any ‘counter-jet’ on kiloparsec-scales, as no emission is visible on the opposite side of the ‘core’. Combining with other VLBI, VLA and MERLIN maps shows that the jet is visible and continuous over a very large range of scales, from 1 pc to 40 kpc.

Bending of the pc scale jet in 3C84

2018 ◽  
Vol 14 (S342) ◽  
pp. 239-241
Author(s):  
A. Hirano ◽  
K. Fujisawa ◽  
K. Niinuma ◽  
Keyword(s):  
Time Scale ◽  
Radio Galaxy ◽  
Brightness Distribution ◽  
Vlbi Observation ◽  
The Core ◽  
Long Period ◽  
Structure Changes ◽  
Observation Network ◽  
Real Change ◽  
Jet Structure

AbstractWe have conducted VLBI monitoring observations for a radio galaxy 3C 84 to investigate how the pc scale jet structure changes over a long period. VERA, a VLBI observation network in Japan, was used for the observation. The C3 component of the jet has continuously moved toward the south from the core. The motion was, however, not straight, but it showed a bending of about 0.3 mas (0.1 pc) with a time scale of 500-1000 days. Two models explaining the bending, local brightness distribution change or real change of the jet traveling direction, are discussed.

scholarly journals 5 Years of VLBI and X-Ray Observations of NRAO 140

1988 ◽  
Vol 129 ◽  
pp. 35-36
Author(s):  
Alan P. Marscher
Keyword(s):  
Flux Density ◽  
Low Frequency ◽  
Total Flux ◽  
X Ray ◽  
The Core ◽  
Vlbi Observations ◽  
Superluminal Motion ◽  
Low Frequency Variability ◽  
Jet Structure

The author and his collaborators have observed NRAO 140 twice at X-ray energies and numerous times with multifrequency VLBI. The VLBI observations reveal a knotty jet structure with superluminal motion of the innermost two knots relative to the core. The VLBI core decreased by about a factor of 2 in flux density between 1980 and late 1984. The X-ray flux also declined by about the same factor during this period. Monitoring at 18 cm during periods of low-frequency variability has revealed pronounced changes in the relative brightnesses of the components of the source while the total flux density has varied by ≲ 10%.

scholarly journals The Radio Jet in 3C418

1984 ◽  
Vol 110 ◽  
pp. 141-143 ◽  
Author(s):  
T.W.B. Muxlow ◽  
M. Jullian ◽  
R. Linfield
Keyword(s):  
Black Hole ◽  
Cone Angle ◽  
The Other ◽  
Simple Solution ◽  
Close Binary ◽  
Radio Structure ◽  
The Core ◽  
Binary Black Hole ◽  
Model Geometry

Models are here presented interpreting the arcsecond radio structure found in the quasar 3C418 as a precessing jet. No simple solution exists and it has been found necessary to complicate the model geometry by allowing the precession cone-angle to increase with time. The timescales suggest the presence of a close binary black-hole system within the quasar core. The modelled behaviour of the precession cone close to the core is explained either by interaction of the jet with the surrounding galactic material or by the observation of the source during the capture of one black-hole by the other.

scholarly journals The Milliarcsecond Core of 3C147 at 6 cm

1984 ◽  
Vol 110 ◽  
pp. 29-30 ◽  
Author(s):  
E. Preuss ◽  
W. Alef ◽  
N. Whyborn ◽  
P.N. Wilkinson ◽  
K.I. Kellermann
Keyword(s):  
Radio Source ◽  
Radio Sources ◽  
Radio Structure ◽  
Extragalactic Radio Sources ◽  
North East ◽  
The North ◽  
Vlbi Observations ◽  
Spectrum Radio ◽  
The One

3C147 is a compact (≲1″), steep spectrum radio source identified with a quasar at z = 0.545 (0″.001 = 7.4 pc; c/Ho = 6000 Mpc and qo = 0.5). The radio structure shown by VLBI observations at 18 cm (Readhead & Wilkinson, 1980; Simon et al., this volume), at 50 cm (Wilkinson et al., 1977), and at 90 cm (Simon et al., 1980 and 1983) shows a bright ‘core’ (60 pc at one end of a ‘jet’ ~0″.2 (1.5 kpc) in length oriented in p.a. ~ −130°. In this sense 3C147 is typical of the one-sided ‘core-jet’ structures commonly found in the centres of other extragalactic radio sources. However, MERLIN observations at 6 cm (Wilkinson, this vol.) and VLA observations at 2 cm (Crane & Kellermann, unpubl.; Readhead et al., 1980) show a larger elongated feature extending ~0″.5 (3.7 kpc) to the North East of the bright core in p.a. ~25° or on the opposite side to the 0″.2 jet.

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