Variable Radio Sources

Fanti, R.; Padrielli, L.; Salvati, M.

doi:10.1007/978-94-011-7565-4_87

Cited by 35 publications

(49 citation statements)

References 19 publications

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“…What is still uncertain is their subsequent evolution. The simplest scenario is that CSOs evolve via Medium-size Symmetric Objects into Large-size Symmetric Objects (Fanti et al, 1995;Readhead et al, 1996b;Owsianik & Conway, 1998). Given the rapid expansion rate of CSOs the sources will spend only a short time in the CSO phase, and it would be expected that only a small fraction of sources would be CSOs.…”

Section: Evolution Of Csosmentioning

confidence: 99%

“…Several theories have been suggested to explain CSOs. It has been suggested that they are a young phase in the development of classical doubles (e.g., Phillips & Mutel, 1982;Fanti et al, 1995;Readhead et al, 1996b) or that they are fairly old sources in which a dense environment inhibits their growth (e.g., van Breugel et al, 1984). Finally it has been proposed that they are a separate class of short lived objects which 'fizzle out' after about 10 4 years .…”

Section: Introductionmentioning

confidence: 99%

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The youngest lobe-dominated radio sources

Owsianik¹,

Conway

Polatidis³

1999

New Astronomy Reviews

225

240

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We present an analysis of multi-epoch global VLBI observations of the Compact Symmetric Objects: 2352+495 and 0710+439 at 5 GHz. Analysis of data spread over almost two decades shows strong evidence for an increase in separation of the outer components of both sources at a rate of ∼ 0.2h −1 c (for q • =0.5 and H • = 100h kms −1 Mpc −1 ). Dividing the overall sizes of the sources by their separation rates implies that these Compact Symmetric Objects have a kinematic age ≪ 10 4 years. These results (and those for other CSOs) strongly argue that CSOs are indeed very young sources and that they are probably evolve into the much larger classical doubles.

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Section: Evolution Of Csosmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

The youngest lobe-dominated radio sources

Owsianik¹,

Conway

Polatidis³

1999

New Astronomy Reviews

225

240

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“…It is therefore generally believed that GPS galaxies evolve into CSS and then FR I and/or FR II radio sources, assuming that they are fuelled for long enough. This makes CSO/GPS galaxies the key objects for studying the early evolution of powerful radio-loud active galactic nuclei (AGN) (Fanti et al 1995;Readhead et al 1996;O'Dea & Baum 1997;Snellen et al 2000b).…”

Section: Introductionmentioning

confidence: 99%

A Parkes half-Jansky sample of GHz peaked spectrum galaxies

Snellen¹,

Lehnert

Bremer³

et al. 2002

Monthly Notices of the Royal Astronomical Society

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This paper describes the selection of a new southern/equatorial sample of gigahertz peaked spectrum (GPS) radio galaxies, and subsequent optical charge‐coupled device imaging and spectroscopic observations using the ESO 3.6‐m telescope. The sample consists of 49 sources with −40° < δ < +15°, |b|>20° and S2.7GHz>0.5 Jy, selected from the Parkes PKSCAT90 survey. Approximately 80 per cent of the sources are optically identified, and approximately half of the identifications have available redshifts. The R‐band Hubble diagram and evolution of the host galaxies of GPS sources are reviewed.

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“…One interpretation of CSSs is that they are young objects (Fanti & Spencer 1996), still in the process of 'drilling' their way through the interstellar medium of the host galaxy before escaping and evolving into the giant radio sources typical of RLQs and radio galaxies of Fanaroff-Riley Type II (Fanti et al 1990). In this model, as the radio source propagates outwards from scales of a few hundred parsecs to several kiloparsecs, changes in the radiation efficiency of the jet will cause the total radio luminosity of the source to decrease by a factor of ϳ10 (Fanti et al 1995;Readhead et al 1996).…”

Section: Comparison With Compact Steep-spectrum Sourcesmentioning

confidence: 99%

The radio properties of radio-quiet quasars

Kukula

Dunlop

Hughes

et al. 1998

Monthly Notices of the Royal Astronomical Society

127

173

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A B S T R A C TAlthough radio-quiet quasars (RQQs) constitute տ 90 per cent of optically identified quasar samples, their radio properties are only poorly understood. In this paper we present the results of a multi-frequency VLA study of 27 low-redshift RQQs. We detect radio emission from 20 objects, half of which are unresolved (Յ 0:24 arcsec). In cases where significant structure can be resolved, double, triple and linear radio sources on scales of a few kpc are found. The radio emission (typically) has a steep spectrum (a ϳ 0:7, where S ϰ n ¹a ), and high brightness temperatures (T B Ն 10 5 K) are measured in some of the radio components. The RQQs form a natural extension to the radio luminosity-absolute magnitude distribution of nearby Seyfert 1s. We conclude that a significant fraction of the radio emission in RQQs originates in a compact nuclear source directly associated with the quasar. There are no significant differences between the radio properties of RQQs with elliptical hosts and those in disc galaxies within the current sample.

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Variable Radio Sources

Cited by 35 publications

References 19 publications

The youngest lobe-dominated radio sources

The youngest lobe-dominated radio sources

A Parkes half-Jansky sample of GHz peaked spectrum galaxies

The radio properties of radio-quiet quasars

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