Analytical Modelling of Linear Size Evolution of Powerful Radio Sources

1996 ◽  
pp. 481-482
Author(s):  
Krzysztof T. Chyży
Keyword(s):  
Analytical Modelling ◽  
Linear Size ◽  
Radio Sources ◽  
Powerful Radio ◽  
Size Evolution

scholarly journals The Angular Size Distribution of Radio Sources at Low Flux Densities

1982 ◽  
Vol 97 ◽  
pp. 393-400
Author(s):  
Ann Downes
Keyword(s):  
Size Distribution ◽  
Flux Density ◽  
Angular Size ◽  
Linear Size ◽  
Radio Sources ◽  
High Flux ◽  
Extragalactic Radio Sources ◽  
Size Evolution

Observations of complete samples of extragalactic radio sources at low and intermediate flux densities are described. Many types of source are found. The angular sizes form a smooth extrapolation from higher flux densities, and can be predicted from the known properties of samples at high flux density either with linear size evolution (for Ω = 1 or Ω = 0 Universes) or without linear size evolution (for Ω = 0). The question of whether such evolution is required therefore remains open.

scholarly journals Analytical Modelling of Linear Size Evolution of Powerful Radio Sources

1996 ◽  
Vol 175 ◽  
pp. 481-482
Author(s):  
Krzysztof T. Chyży
Keyword(s):  
Ambient Medium ◽  
Surrounding Medium ◽  
Constant Density ◽  
Radio Sources ◽  
Powerful Radio ◽  
Size Evolution ◽  
Bulk Energy ◽  
High Mach ◽  
Relativistic Particles

We assume that two continuous, supersonic jets of plasma advance into a uniform surrounding medium of constant density and pressure. In terms of fluid dynamics their propagation is described by the kinetic model suitable for high Mach number flows, which likely occur in edge-brightened powerful radio sources. In this approximation the jet flowing energy is dominated by the bulk energy of thermal material. The end of the jet enters the undisturbed ambient medium and forms a front shock, where the supplied bulk energy is in situ transferred to relativistic particles and magnetic field.

scholarly journals The Emission Line Properties of the 3CR Radio Galaxies at Redshift One: Shocks, Evolution, and the Alignment Effect

1999 ◽  
Vol 194 ◽  
pp. 241-245
Author(s):  
Philip Best ◽  
Huub Röttgering ◽  
Malcolm Longair
Keyword(s):  
Emission Line ◽  
Radio Source ◽  
Velocity Structure ◽  
Radio Galaxies ◽  
Linear Size ◽  
Continuum Emission ◽  
Radio Sources ◽  
Powerful Radio ◽  
Alignment Effect ◽  
Optical Continuum

The results of a deep spectroscopic campaign on powerful radio galaxies with redshifts z ˜ 1, to investigate in detail their emission line gas properties, are presented. Both the 2-dimensional velocity structure of the [OII] 3727 emission line and the ionisation state of the gas are found to be strongly dependent upon the linear size (age) of the radio source in a manner indicative of the emission line properties of small (young) radio sources being dominated by the passage of the radio source shocks. The consequences of this evolution throughout the few x107 year lifetime of the radio source are discussed, particularly with relation to the alignment of the UV–optical continuum emission of these objects along their radio axis, the nature of which shows similar evolution.

scholarly journals The Linear-Size Evolution of Classical Double Radio Sources

1995 ◽  
Vol 451 ◽  
pp. 76 ◽  
Author(s):  
Mark J. Neeser ◽  
Stephen A. Eales ◽  
J. Duncan Law-Green ◽  
J. Patrick Leahy ◽  
Steve Rawlings
Keyword(s):  
Linear Size ◽  
Radio Sources ◽  
Size Evolution

scholarly journals Active Nuclei and Redshift Problems

1983 ◽  
Vol 6 ◽  
pp. 531-533
Author(s):  
Geoffrey Burbidge
Keyword(s):  
Galactic Nuclei ◽  
Seyfert Galaxies ◽  
Radio Sources ◽  
Powerful Radio ◽  
Radiation Mechanism ◽  
X Ray ◽  
Major Interest ◽  
Relativistic Particles

More than 20 years ago V. A. Ambartsumian proposed that much of the activity in galaxies was dominated and even generated by their nuclei. Subsequent observational work in radio, optical and x-ray frequencies has borne out his prophecy, and major interest has centered about the nature of the machine in the galactic nucleus. The major characteristic of this machine is that it releases energy rapidly and often spasmodically by processes which are not thermonuclear in origin.The original studies which led to the conclusion that nuclei were all important were observations of the powerful radio sources and Seyfert galaxies, and evidence for the ejection of gas from galaxies of many types. The realization that the synchrotron mechanism was the dominant radiation mechanism and the later studies of Compton radiation were fundamental in leading to the conclusion that large fluxes of relativistic particles must be generated in galactic nuclei.

scholarly journals Erratum: A sample of powerful radio sources for VLBI studies

1986 ◽  
Vol 222 (4) ◽  
pp. 895-895
Author(s):  
T. V. Cawthorne ◽  
P. A. G. Scheuer ◽  
I. Morison ◽  
T. W. B. Muxlow
Keyword(s):  
Radio Sources ◽  
Powerful Radio

Elliptical Galaxies—Getting to the Heart

1990 ◽  
Vol 8 (3) ◽  
pp. 238-242
Author(s):  
Elaine M. Sadler
Keyword(s):  
Optical Properties ◽  
Elliptical Galaxy ◽  
Elliptical Galaxies ◽  
Radio Sources ◽  
Powerful Radio

AbstractElliptical galaxies are at first sight a remarkably homogenous class of objects, yet some of them produce large and enormously powerful radio sources while others remain more or less quiescent. Why should this be so? What prompts the nucleus of an elliptical galaxy to become ‘active’? What, if anything, do elliptical galaxies have in common with the bulges of spirals? Here, I review some of the radio and optical properties of nearby elliptical galaxies, with special emphasis on events which take place within the central kiloparsec.

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