Survey of a complete sample of southern extragalactic radio sources

1993 ◽  
Vol 105 ◽  
pp. 1680 ◽  
Author(s):  
M. Tornikoski ◽  
E. Valtaoja ◽  
H. Terasranta ◽  
M. Lainela ◽  
M. Bramwell ◽  
...  
Keyword(s):  
Radio Sources ◽  
Complete Sample ◽  
Extragalactic Radio Sources

scholarly journals VLBI Survey of a Complete Sample of Active Nuclei and Quasars

1984 ◽  
Vol 110 ◽  
pp. 15-24 ◽  
Author(s):  
T. J. Pearson ◽  
A.C.S. Readhead
Keyword(s):  
Flux Density ◽  
Radio Sources ◽  
Complete Sample ◽  
Limited Sample ◽  
Extragalactic Radio Sources ◽  
5 Ghz ◽  
Number Of Classes ◽  
Compact Sources ◽  
Continuous Range

We have conducted a VLBI survey of a complete, flux-density limited sample of 65 extragalactic radio sources, selected at 5 GHz. We have made hybrid maps at 5 GHz of all of the sources accessible to the Mark-II system. The sources can be divided provisionally into a number of classes with different properties: central components of extended double sources, steep-spectrum compact sources, very compact (almost unresolved) sources, asymmetric sources (sometimes called “core-jet” sources), and “compact double” sources. It is not yet clear whether any of these classes is physically distinct from the others, or whether there is a continuous range of properties.

scholarly journals Intensity Variations in Extragalactic Radio Sources at 13 cm

1972 ◽  
Vol 44 ◽  
pp. 224-224 ◽  
Author(s):  
G. D. Nicolson
Keyword(s):  
Low Frequency ◽  
Secular Change ◽  
Radio Sources ◽  
Complete Sample ◽  
Frequency Spectra ◽  
Extragalactic Radio Sources ◽  
The Relationship

Results of a three-year investigation into the variability of 55 Parkes sources at 13 cm are presented. Thirty-six of the sources comprise a complete sample of QSS with fluxes exceeding 2 flux units. The remaining sources include most other known or likely variables stronger than 2 flux units. The relationship between spectra and variability in QSS is investigated and it is confirmed that variables generally have flat low frequency spectra. A possible relationship between redshift and specific types of intensity variations is considered. Limits on the secular change in the intensity of non-variable QSS are set and are generally found to be ± 1.5% p.a. at 13 cm. Results for the remaining 19 sources are discussed and some preliminary findings of an extension patrol to include weaker sources in the range 1-2 flux units are given.

scholarly journals The Evolution of Linear Sizes

1982 ◽  
Vol 97 ◽  
pp. 401-410
Author(s):  
V. K. Kapahi ◽  
C. R. Subrahmanya
Keyword(s):  
Strong Correlation ◽  
Angular Size ◽  
Inverse Correlation ◽  
Radio Sources ◽  
Radio Luminosity ◽  
Complete Sample ◽  
Extragalactic Radio Sources ◽  
Rule Out

Possible evidence that the linear sizes of extragalactic radio sources were smaller at earlier epochs was first provided by the angular size redshift (θ-z) relation for double radio quasars (Legg 1970, Miley 1971, Wardle and Miley 1974). But because of the strong correlation between redshift (z) and radio luminosity (P) in flux limited radio samples, it is hard to decide if the observed decrease in sizes with z is caused by an epoch dependence of linear sizes (ℓ) or by an inverse correlation between P and ℓ. Several authors (eg. Stannard and Neal 1977, Wardle and Potash 1977, Hooley ET AL. 1978, Wills 1979, Masson 1980) have attempted to separate the two effects by comparing the properties of quasars from the 3CR survey with those from the 4C and Parkes samples. Although most of these studies appear to marginally favour a P-ℓ correlation, none of them can rule out even a fairly strong evolution in ℓ with z. Apart from the small numbers involved, the difficulty is that 3C and 4C quasars do not differ a great deal in their redshifts or luminosities. A complete sample of quasars at much weaker flux levels would be quite valuable in this regard.

scholarly journals An Atlas of Extragalactic Radio Sources

1996 ◽  
Vol 175 ◽  
pp. 157-158 ◽  
Author(s):  
J.P. Leahy ◽  
A.H. Bridle ◽  
R.G. Strom
Keyword(s):  
High Resolution ◽  
Line Emission ◽  
Radio Sources ◽  
X Rays ◽  
Complete Sample ◽  
High Quality ◽  
Extragalactic Radio Sources ◽  
Optical Line

Our Atlas of Extragalactic Radio Sources will present high-quality images of the nearer half of “3CRR”, the sample defined by Laing, Riley & Longair (1983). This is the best-studied complete sample of extragalactic radio sources. All 173 members have secure redshifts and most have been imaged in the radio at high resolution. There is also copious information on their optical line emission, and many have been detected in the sub-mm, FIR, and in X-rays. 3CRR is widely used as a baseline against which fainter, higher-redshift samples can be compared to define the evolution of the population (e.g. Neeser et al. 1995; Law-Green, this conference).

The low-frequency spectra of a complete sample of extragalactic radio sources

1984 ◽  
Vol 89 ◽  
pp. 323 ◽  
Author(s):  
L. Gregorini ◽  
F. Mantovani ◽  
A. Eckart ◽  
P. Biermann ◽  
A. Witzel ◽  
...  
Keyword(s):  
Low Frequency ◽  
Radio Sources ◽  
Complete Sample ◽  
Frequency Spectra ◽  
Extragalactic Radio Sources

scholarly journals Spatial Structures of a Complete Sample of Extragalactic Radio Sources North of Declination 70°

1984 ◽  
Vol 110 ◽  
pp. 65-66
Author(s):  
A. Eckart ◽  
A. Witzel
Keyword(s):  
Optical Spectroscopy ◽  
Radio Sources ◽  
Spatial Structures ◽  
Complete Sample ◽  
X Ray ◽  
Extragalactic Radio Sources ◽  
Bl Lac ◽  
5 Ghz

With the aim of studying the spatial structures of a complete sample of radio sources found at 6 cm wavelength we selected 13 sources from the “S5–survey” (Kühr et al., 1981) which fulfil the following criteria1) δ > 70°, |bII| > 10°2) S5 GHz > 1 Jy (at the epoch of the S5–survey)3) α5 GHz2.7 GHz > − 1.5 (S ∝ να)6 of these sources are identified by means of optical spectroscopy with QSOs, 6 are BL Lac-type objects, and the identification of 1 source is presently unknown. Observations at frequencies ranging from radio to X-ray have been reported (Biermann et al., 1981; Biermann et al., 1982; Eckart et al., 1982).

scholarly journals The polarimetric multi-frequency radio sources properties

2016 ◽  
Vol 25 (11) ◽  
pp. 1640005 ◽  
Author(s):  
Vincenzo Galluzzi ◽  
Marcella Massardi
Keyword(s):  
Power Spectrum ◽  
Cosmic Microwave Background ◽  
State Of The Art ◽  
The State ◽  
Radio Sources ◽  
Microwave Background ◽  
Complete Sample ◽  
Angular Power Spectrum ◽  
Extragalactic Radio Sources ◽  
Compact Array

The polarization properties of extragalactic radio sources at frequencies higher than [Formula: see text]GHz are still poorly constrained. However, their characterization would provide invaluable information about the physics of the emission processes and is crucial to estimate their contamination as foregrounds of the polarized Cosmic Microwave Background (CMB) angular power spectrum on scales [Formula: see text]arcmin. In this contribution, after summarizing the state-of-the-art of polarimetric observations in the millimetric wavelength bands, we present our observations of a complete sample of 53 sources with [Formula: see text]mJy carried out with the Australia Telescope Compact Array (ACTA) between [Formula: see text] and [Formula: see text]GHz. The analysis clearly shows that polarization properties cannot be simply inferred from total intensity ones, as the spectral behaviors of the two signals are typically different.

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