scholarly journals Bent Jets in Radio Quasars

1982 ◽  
Vol 97 ◽  
pp. 137-138
Author(s):  
Susan G. Neff
Keyword(s):  
Hot Spots ◽  
Radio Galaxies ◽  
Plasma Instability ◽  
Radio Sources ◽  
Central Engine ◽  
Central Nozzle ◽  
Quasars And Radio Galaxies

How is energy transported out from the central engine in quasars and radio galaxies to the distant radio lobes? This problem has been around since the early discovery of classical double radio sources, and is still not answered in detail. The idea of relativistic beams was first suggested by Martin Rees as a means of transporting plasma out of the nucleus (Rees, 1971, Blandford and Rees, 1974). This idea gained support first from the discovery of hot spots in the radio lobes of these large classical double sources, and later by observations of the beams themselves in radio galaxies. As more jets were observed, it became obvious that they were often curved, serpentine, or even sharply bent. This behavior has been modeled as precession of the central nozzle (Bridle et al., 1976, Ekers et al., 1978), as nuclear refraction (Henriksen et al., 1981), as a growing plasma instability (Hardee, 1981) and as various combinations of the above. At the present time, it seems safest to conclude that there are some examples of each of these processes known.

scholarly journals VLA observations of 20 FR II radio sources at 8.4 GHz

2019 ◽  
Vol 364 (10) ◽  
Author(s):  
Ilias Fernini
Keyword(s):  
High Resolution ◽  
Hot Spots ◽  
Radio Galaxies ◽  
Class Ii ◽  
Outer Edge ◽  
Radio Sources ◽  
Large Sample ◽  
Contour Maps ◽  
Surrounding Environment

Abstract We report the last observational paper of hot spots for 20 Fanaroff-Riley class II (FR II) sources. These sources are part of a large sample of 98 FR II to study the unification scheme of FR II radio galaxies (RGs) and quasars (QSRs) using the hotspots (HSs) location and morphology. High-resolution VLA observations at 8.4 GHz were conducted for the whole sample. The investigation of HSs properties in FR II radio sources is essential for a better understanding of the dynamics related to the objects and their impact on the surrounding environment. HSs were classified into edged and recessed types, where the former is located at a radio lobe’s outer edge, and the latter is embedded within the lobe. The present sub-sample contains 12 RGs and 8 QSRs. Radio contour maps for each source were presented using the VLA in its A and B configurations. In total, we have identified 18 HSs for these 20 radio sources. The 12 RGs possess 8 edged HSs and 2 recessed HSs. The 8 QSRs possess 6 edged HSs and 2 recessed HSs. Out of the 14 edged HSs, RGs and QSRs possess $\sim57\%$∼57% and $\sim43\%$∼43%, respectively. A thorough morphological discussion of the 20 sources with their HSs is presented in the present work.

scholarly journals Extragalactic jets as probes of distant clusters of galaxies and the clusters occupied by bent radio AGN (COBRA) survey

2014 ◽  
Vol 10 (S313) ◽  
pp. 315-320
Author(s):  
Elizabeth L. Blanton ◽  
Rachel Paterno-Mahler ◽  
Joshua D. Wing ◽  
M. L. N. Ashby ◽  
Emmet Golden-Marx ◽  
...  
Keyword(s):  
Radio Galaxies ◽  
Radio Sources ◽  
Clusters Of Galaxies ◽  
Wide Range ◽  
Extragalactic Jets ◽  
Large Survey ◽  
Kinetic Mode ◽  
Group Environments ◽  
Initial Results ◽  
Quasars And Radio Galaxies

AbstractWe are conducting a large survey of distant clusters of galaxies using radio sources with bent jets and lobes as tracers. These radio sources are driven by AGN and achieve their bent morphologies through interaction with the surrounding gas found in clusters of galaxies. Based on low-redshift studies, these types of sources can be used to identify clusters very efficiently. We present initial results from our survey of 653 bent-double radio sources with optical hosts too faint to appear in the SDSS. The sample was observed in the infrared with Spitzer, and it has revealed ~200 distant clusters or proto-clusters in the redshift range z ~ 0.7 - 3.0. The sample of bent-doubles contains both quasars and radio galaxies enabling us to study both radiative and kinetic mode feedback in cluster and group environments at a wide range of redshifts.

scholarly journals Soon After the Birth of Radio Sources

2001 ◽  
Vol 205 ◽  
pp. 112-113
Author(s):  
I. Owsianik ◽  
J.E. Conway ◽  
A.G. Polatidis
Keyword(s):  
Early Stage ◽  
Radio Galaxies ◽  
Radio Sources ◽  
Periodic Activity ◽  
Central Engine ◽  
Expansion Speed ◽  
Kinematic Studies ◽  
Evolution With Time

Compact Symmetric Objects (CSOs) represent an early stage in the life of radio galaxies. Our kinematic studies over a 20 year timebase have unambiguously demonstrated that they expand fast and that the radio activity is recently born. The CSO evolution with time is however still a matter of investigation. If they are progenitors of the “classical double” radio sources, then in order to fit the the observed statistics of radio sources, CSOs must have decrease their luminosity and expansion speed with time. It is also possible that CSOs represent a phase of periodic activity of the central engine; in this case the presence of the old activity in the form of extended weak emission, should be observed.

scholarly journals An Updated Multi-Wavelength Radio and Optical Catalog of Quasars and Radio Galaxies

2013 ◽  
Vol 9 (S304) ◽  
pp. 238-239 ◽  
Author(s):  
Amy E. Kimball ◽  
Željko Ivezić
Keyword(s):  
Spectral Index ◽  
Radio Galaxies ◽  
Radio Sources ◽  
Large Area ◽  
Sky Surveys ◽  
The North ◽  
Multi Wavelength ◽  
Optical Surveys ◽  
Quasars And Radio Galaxies ◽  
North Galactic

AbstractWe present a catalog of millions of radio sources, created by consolidating large-area radio and optical surveys GB6 (6cm), FIRST (20cm), NVSS (20cm), WENSS (92cm), VLSS (4m), and SDSS DR9 (optical). The region where all surveys overlap covers 3269 deg2 in the North Galactic Cap, and contains >160,000 20-cm sources, with about 12,000 detected in all five radio surveys and over one-third detected optically. Combining parameters from the sky surveys allows easy and efficient classification by radio and optical morphology and radio spectral index. The catalog is available at http://www.atnf.csiro.au/people/Amy.Kimball/radiocat.shtml.

scholarly journals SpitzerObservations of 3C Quasars and Radio Galaxies: Mid‐Infrared Properties of Powerful Radio Sources

2007 ◽  
Vol 660 (1) ◽  
pp. 117-145 ◽  
Author(s):  
K. Cleary ◽  
C. R. Lawrence ◽  
J. A. Marshall ◽  
L. Hao ◽  
D. Meier
Keyword(s):  
Radio Galaxies ◽  
Radio Sources ◽  
Powerful Radio ◽  
Mid Infrared ◽  
Quasars And Radio Galaxies

The radio sources CTA 21 and OF+247: The hot spots of radio galaxies

2013 ◽  
Vol 57 (6) ◽  
pp. 423-428 ◽  
Author(s):  
V. S. Artyukh ◽  
S. A. Tyul’bashev ◽  
P. A. Chernikov
Keyword(s):  
Hot Spots ◽  
Radio Galaxies ◽  
Radio Sources

scholarly journals The Jets in FRII Radio Galaxies with z < 0.3

1996 ◽  
Vol 175 ◽  
pp. 153-154
Author(s):  
Martin Hardcastle
Keyword(s):  
Hot Spots ◽  
Detection Rate ◽  
Energy Transport ◽  
Radio Galaxy ◽  
Radio Galaxies ◽  
Radio Sources

If we believe that jets trace the energy transport in radio sources, we might in principle expect to see them in every classical double radio galaxy with compact hot spots. Until recently the detection rate of jets in FRII radio galaxies has been low, although most FRII quasars have bright one-sided jets. However, it seems likely that this is due to lack of sensitivity. Black et al. (1992) found jets in up to 70% of a sample of FRII galaxies with z < 0.15. We have observed the FRII sources in Laing et al. (1983) with 0.15 < z < 0.3 and discuss results from the combined samples.

scholarly journals Physical Conditions in CSS Radio Sources

2002 ◽  
Vol 199 ◽  
pp. 211-212
Author(s):  
S. A. Tyul'bashev ◽  
P. A. Tchernikov
Keyword(s):  
Phased Array ◽  
Low Frequency ◽  
Radio Galaxies ◽  
Radio Sources ◽  
Interplanetary Scintillation ◽  
Physical Conditions ◽  
Spectrum Radio ◽  
Quasars And Radio Galaxies

Interplanetary scintillation observations of 56 compact steep-spectrum radio sources have been carried out at 102 MHz on the Large Phased Array. Observations have shown that 42 sources have low frequency cut-offs in their spectra. The physical conditions in the compact components of the quasars and radio galaxies studied are estimated.

scholarly journals Relations Between Radio and Optical Properties of Radio Sources - Radio Astronomer's Point of View

1977 ◽  
Vol 74 ◽  
pp. 237-243
Author(s):  
J. M. Riley ◽  
C. J. Jenkins
Keyword(s):  
Optical Properties ◽  
Radio Galaxies ◽  
Point Of View ◽  
Radio Sources ◽  
Optical Identification ◽  
Complete Sample ◽  
Radio Structure ◽  
Quasars And Radio Galaxies

One particular aspect of the relations between the radio and optical properties of radio sources has been examined for a complete sample of 3CR sources, namely the relation between the radio structure of a source and its optical identification. Possible differences between the radio structures of quasars and radio galaxies are investigated, and the data provide clues as to the optical nature of the unidentified sources.

scholarly journals The Linear Polarization of Radio Sources Between 11 and 20 cm Wavelength. II. Polarization and Related Properties of Extragalactic Sources

1969 ◽  
Vol 22 (1) ◽  
pp. 107 ◽  
Author(s):  
FF Gardner ◽  
JB Whiteoak
Keyword(s):  
Radiation Spectrum ◽  
Radio Galaxies ◽  
Radio Sources ◽  
Evolutionary Sequence ◽  
Small Component ◽  
High Brightness ◽  
High Frequencies ◽  
Source Characteristics ◽  
Polarization Characteristics ◽  
Quasars And Radio Galaxies

The polarization properties of quasars, radio galaxies, and unidentified objects at 11 and 20 cm wavelength are discussed and compared with other source characteristics. For some quasars, scintillation and spectral data are in accord with current ideas that the sources comprise a small component radiating only at high frequencies and a larger component with a radiation spectrum similar to radio galaxies. The polarization is associated with this second component. For radio galaxies, the lower polarization of scintillators and a decrease of luminosity with increasing polarization suggest that sources of high brightness have low polarization. In spectral and polarization characteristics, the unidentified sources are similar to radio galaxies. Source evolution is discussed; the results suggest that quasars and radio galaxies evolve separately rather than represent different stages of a single evolutionary sequence.

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