Luminosity Function of Radio Sources

1962 ◽  
Vol 11 (02) ◽  
pp. 464
Author(s):  
R. Minkowski
Keyword(s):  
Luminosity Function ◽  
Radio Sources

scholarly journals Statistical Effects of Doppler Beaming and Malmquist Bias on Flux-Limited Samples of Compact Radio Sources

1998 ◽  
Vol 164 ◽  
pp. 137-138
Author(s):  
Matthew L. Lister ◽  
Alan P. Marscher
Keyword(s):  
Active Galactic Nuclei ◽  
Luminosity Function ◽  
Galactic Nuclei ◽  
Lorentz Factor ◽  
Radio Sources ◽  
Apparent Velocity ◽  
Parent Population ◽  
Relativistic Jet ◽  
Spectrum Radio ◽  
Statistical Effects

AbstractWe examine the effects of Doppler beaming on flux-limited samples of compact extragalactic radio sources using Monte Carlo simulations. We incorporate a luminosity function and z-distribution for the parent population, and investigate models in which the unbeamed synchrotron luminosity L of a relativistic jet is related to its bulk Lorentz factor Γ. The predicted flux density, redshift, monochromatic luminosity, and apparent velocity distributions of our simulated flux-limited samples are compared to the Caltech-Jodrell Bank (CJF) sample of flat-spectrum, radio core-dominated active galactic nuclei (AGNs).We find that a relation between L and Γ is not needed to reproduce the characteristics of the CJF sample. Introducing a positive correlation between these quantities results in an underabundance of objects with high viewing angles, while a negative correlation gives generally poor fits to the data.

scholarly journals Clusters of Galaxies and Radio Sources

1977 ◽  
Vol 74 ◽  
pp. 305-316 ◽  
Author(s):  
Walter Jaffe
Keyword(s):  
Luminosity Function ◽  
Radio Galaxies ◽  
Radio Sources ◽  
Clusters Of Galaxies ◽  
Cluster Environment ◽  
Different Characteristics

For some time there have been suggestions that there is a special association of radio galaxies with rich clusters of galaxies, and more recently that the radio galaxies in clusters may show different characteristics from those outside. I will discuss the evidence for three types of such differences, in luminosity function, morphology, and occurance of steep spectrum sources. In each case I will try to connect any difference I find to the cluster environment.

scholarly journals On Cosmological Evolution of Quasars

1987 ◽  
Vol 124 ◽  
pp. 649-653
Author(s):  
Jerzy Machalski
Keyword(s):  
Luminosity Function ◽  
Absolute Magnitude ◽  
Cosmological Evolution ◽  
Recent Attempt ◽  
Radio Sources ◽  
General Radio ◽  
Radio Detection ◽  
Translation Function ◽  
Number Counts ◽  
Radio Luminosity Function

Hereafter the term “quasar” is applied to both optically selected (and/or spectroscopically confirmed) UVX objects, and to radio-detected objects of that kind. A recent attempt to model number-counts of radio-selected QSOs (Condon, private communication) has revealed that the counts cannot be modelled by simply translating the general radio luminosity function (RLF) leaving the cosmological evolution unchanged. While it may be true that the radio sources in QSOs evolve in the same way as do all radio sources (i.e. translation function), the radio sources are probably not always in QSOs. In particular, it may be that increasing the luminosity (especially the core luminosity) of a radio source increases the probability that it is in a QSO. If that is true, a radio detection rate of optical QSOs should be strongly dependent on the optical (core) luminosity, i.e. on the absolute magnitude.

scholarly journals Complete Samples of Flat Spectrum Radio Sources from the Parkes 2.7 GHz Survey

1988 ◽  
Vol 129 ◽  
pp. 77-78
Author(s):  
David L. Jauncey ◽  
G. L. White ◽  
B. R. Harvey ◽  
M. J. Batty ◽  
A. E. Wright ◽  
...  
Keyword(s):  
Size Distribution ◽  
Reference Frame ◽  
Southern Hemisphere ◽  
Luminosity Function ◽  
Space Distribution ◽  
Radio Sources ◽  
Spectrum Radio ◽  
The Individual ◽  
Galactic Radio

We are investigating complete samples of southern hemisphere flat spectrum extra-galactic radio sources drawn from the Parkes 2.7 GHz Survey (see Bolton et al. 1979 and references therein). These samples are being used for a variety of investigations, including a determination of the space distribution and luminosity function of radio QSOs, their radio size distribution, as well as the structures of the individual sources. Accurate positions are being determined, as well, in order to establish an extra-galactic position reference frame in the southern hemisphere.

scholarly journals Quasar Surveys

1986 ◽  
Vol 119 ◽  
pp. 17-32
Author(s):  
M. G. Smith
Keyword(s):  
Luminosity Function ◽  
Seyfert Galaxies ◽  
Radio Sources ◽  
Selection Effects ◽  
Spectral Evolution ◽  
X Ray ◽  
Spectrum Radio ◽  
Show Evidence ◽  
Optical Surveys ◽  
Radio Luminosity Function

A review is given of progress in surveys for quasars at frequencies from radio to x-ray. Radio results show evidence for a decline in the radio luminosity function for flat-spectrum radio sources at redshifts z > 2. The IRAS survey is uncovering hitherto unknown dusty Seyfert galaxies. Optical surveys, which yield the largest number of QSOs per square degree, may suffer from selection effects which depend on intrinsic luminosity, redshift, and spectral evolution - particularly above redshift 2. Below redshifts of about 2.3, the optical magnitude-redshift plane is being filled in to the point where the evolution of the luminosity function can be seen directly. The statistics of quasar pair separations provide the best evidence so far for quasar clustering.The existence of many potentially significant selection effects means that a multi-frequency approach to quasar surveys is likely to prove essential to an understanding of the evolutionary behaviour of the quasar population as a whole.

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