Spectral ageing in a sample of 14 high-luminosity double radio sources

Liu, Ronghui; Pooley, G. G.; Riley, J. M.

doi:10.1093/mnras/257.4.545

Cited by 132 publications

(188 citation statements)

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“…3C 299: Due in part to the large lobe length asymmetry of this source, the eastern lobe of this source was once thought to be a separate compact steep-spectrum source, which is why many maps show only the eastern component. Using the core position from the L-band map of Leahy, Bridle, and Strom, 2 the L-band map of Liu, Pooley, & Riley (1992) was used for FR measurements because the L-band map of Leahy et al is probably undersampled. The Q-values from these two maps differ by 17%, probably due to differences in resolution.…”

Section: Comments On Individual Sourcesmentioning

confidence: 99%

A Study of 3CR Radio Galaxies from [ITAL][CLC]z[/CLC][/ITAL] = 0.15 to [ITAL][CLC]z[/CLC][/ITAL] = 0.65. II. Evidence for an Evolving Radio Structure

Harvanek

Stocke

2002

The Astronomical Journal

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Radio morphology data have been collected for a sample of radio galaxies from the Revised Third Cambridge Catalog in the redshift range 0.15 < z < 0.65. Radio structure parameters including largest physical size, projected bending angle ( ), lobe length asymmetry (Q), and hot spot placement (Fanaroff-Riley ratio) have been measured from the highest-quality radio maps available. Combined with similar data for quasars in the same redshift range, these morphology data are used in conjunction with a quantification of the richness of the cluster environment around these objects (the amplitude of the galaxy-galaxy spatial covariance function, B gg ) to search for indirect evidence of a dense intracluster medium (ICM). This is accomplished by searching for confinement and distortions of the radio structure that are correlated with B gg . Correlations between physical size and hot spot placement with B gg show evidence for an ICM only at z 0.4, but there are no correlations at z ! 0.4, suggesting an epoch of z $ 0.4 for the formation of the ICM in these Abell richness class 0-1, FR2-selected clusters. X-ray-selected clusters at comparable redshifts, which contain FR1 type sources exclusively, are demonstrably richer than the FR2-selected clusters found in this study. The majority of the radio sources with high B gg values at z 0.4 can be described as '' fat doubles '' or intermediate FR2-FR1s. The lack of correlation between B gg and or B gg and Q suggests that these types of radio source distortion are caused by something other than interaction with a dense ICM. Therefore, a large cannot be used as an unambiguous indicator of a rich cluster around powerful radio sources. These results support the hypothesis made in our earlier paper that cluster quasars fade to become FR2s, then FR1s, on a timescale of 0.9 Gyr (for H 0 = 50 km s À1 Mpc À1 ).

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Section: Comments On Individual Sourcesmentioning

confidence: 99%

A Study of 3CR Radio Galaxies from [ITAL][CLC]z[/CLC][/ITAL] = 0.15 to [ITAL][CLC]z[/CLC][/ITAL] = 0.65. II. Evidence for an Evolving Radio Structure

Harvanek

Stocke

2002

The Astronomical Journal

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“…Polatidis & Conway (2003) for a review -whereas for larger sources, i.e. MSOs (Murgia et al 1999) and LSOs (Alexander & Leahy 1987;Liu et al 1992), spectral ages have been estimated.…”

Section: Introductionmentioning

confidence: 99%

FIRST-based survey of Compact Steep Spectrum sources

Kunert-Bajraszewska¹,

Marecki²,

Thomasson

et al. 2005

A&A

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Abstract.A new sample of candidate Compact Steep Spectrum (CSS) sources that are much weaker than the CSS source prototypes has been selected from the VLA FIRST catalogue. MERLIN "snapshot" observations of the sources at 5 GHz indicate that six of them have an FR II-like morphology, but are not edge-brightened as is normal for Medium-sized Symmetric Objects (MSOs) and FR IIs. Further observations of these six sources with the VLA at 4.9 GHz and MERLIN at 1.7 GHz, as well as subsequent full-track observations with MERLIN at 5 GHz of what appeared to be the two sources of greatest interest are presented. The results are discussed with reference to the established evolutionary model of CSS sources being young but in which not all of them evolve to become old objects with extended radio structures. A lack of stable fuelling in some of them may result in an early transition to a so-called coasting phase so that they fade away instead of growing to become large-scale objects. It is possible that one of the six sources (1542+323) could be labelled as a prematurely "dying" MSO or a "fader".

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“…The estimated speed within the limits of error, supports the assumption of constant advance speed of hotspots, though there seems to be a mild increase at the CSO (〈 ̅ 〉~ 0. Observations of the synchrotron radiation spectrum of extragalactic radio sources (assuming equipartition magnetic field) have led to the estimation of the advance speed of the hotspots for most powerful extragalactic radio sources as ~0.2 − 0.3 (Myers & Spangler 1985;Liu et al 1992). Using the prevalence of long lobe of radio sources, Longair & Riley (1979) estimated that the expansion speed of the lobes in general cannot be more than ~ 0.25.…”

Section: Discussionmentioning

confidence: 99%

Hotspot Advance Speed - Hotspot Size/Core-Hotspot Length Relation

Onuchukwu

2015

ILCPA

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ABSTRACT. We examined the evolution of extragalactic radio sources using the observed corehotspot length and hotspot size. Analysis indicates a fairly strong positive correlation in the ratio of core-hotspot length to hotspot size between that of the approaching arm and the receding arm with a correlation coefficient of ~ 0.7. Simple kinematic consideration enabled us to obtain an expression to constrain the advance speed of hotspots. In general, the average projected hotspot advance speed estimated for our sample ranges from 0.13 ≤ 〈 〉 ≤ 0.40

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Spectral ageing in a sample of 14 high-luminosity double radio sources

Cited by 132 publications

References 0 publications

A Study of 3CR Radio Galaxies from [ITAL][CLC]z[/CLC][/ITAL] = 0.15 to [ITAL][CLC]z[/CLC][/ITAL] = 0.65. II. Evidence for an Evolving Radio Structure

A Study of 3CR Radio Galaxies from [ITAL][CLC]z[/CLC][/ITAL] = 0.15 to [ITAL][CLC]z[/CLC][/ITAL] = 0.65. II. Evidence for an Evolving Radio Structure

FIRST-based survey of Compact Steep Spectrum sources

Hotspot Advance Speed - Hotspot Size/Core-Hotspot Length Relation

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