The Nature and Evolution of Classical Double Radio Sources from Complete Samples

Blundell, Katherine M.; Rawlings, Steve; Willott, Chris J.

doi:10.1086/300721

Cited by 300 publications

(447 citation statements)

References 122 publications

(166 reference statements)

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“…Such interactions could both trigger a phase of jet production from the central engine and easily lead to asymmetric distributions of gas in the inner regions for at least the <10 7 yr during which the jets propagate through the galactic ISM. The propagation through denser media also implies higher efficiencies for conversion of jet power to radio luminosity (Gopal-Krishna & Wiita 1991;Blundell et al 1999); this concept is supported by the recent findings of Arshakian & Longair (2000) that more luminous sources are more asymmetric. Our model calculations assume two intrinsically symmetric jets propagating outwards in opposite directions in pressure balance between the momentum flux density of the beam and ram pressure of the external medium, so the equation for the growth of one jet is (e.g., Scheuer 1974),…”

Section: Analytical Models For Jets Propagating In An Asymmetric Envimentioning

confidence: 67%

Jet propagation and the asymmetries of CSS radio sources

Jeyakumar

Wiita

Saikia

et al. 2005

A&A

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Abstract. As Compact Steep Spectrum radio sources have been shown to be more asymmetrical than larger sources of similar powers, there is a high probability that they interact with an asymmetric medium in the central regions of the host elliptical galaxy. We consider a simple analytical model of the propagation of radio jets through a reasonable asymmetric environment and show that they can yield the range of arm-length and luminosity asymmetries that have been observed. We then generalize this to allow for the effects of orientation, and quantify the substantial enhancements of the asymmetries that can be produced in this fashion. We present two-dimensional and three-dimensional simulations of jets propagating through multi-phase media and note that the results from the simulations are also broadly consistent with the observations.

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Section: Analytical Models For Jets Propagating In An Asymmetric Envimentioning

confidence: 67%

Jet propagation and the asymmetries of CSS radio sources

Jeyakumar

Wiita

Saikia

et al. 2005

A&A

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“…Sensitive, single-dish observations may reveal extended lower surface brightness structure. Blundell et al (1999) note an absence of small low-power sources in the P 151 MHz versus D diagram. The compact radioexcess objects may fill this region, although inferring the flux density at 151 MHz from our observations at gigahertz frequencies is highly uncertain, as synchrotron self-absorption may produce a turnover in the spectrum at megahertz frequencies.…”

Section: Radio Powersmentioning

confidence: 89%

Radio-ExcessIRASGalaxies. III. Radio Properties

et al. 2004

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This is the third in a series of papers discussing the nature of radio-excess IRAS galaxies. This paper investigates in more detail the radio source properties of the radio-excess galaxies that are luminous in the far infrared (FIR). Spectral energy distributions derived from data from the Australia Telescope Compact Array confirm that the radio spectral energy distributions of the FIR-luminous radio-excess galaxies are mostly steep or show a turnover at gigahertz frequencies. VLBI snapshot data indicate that most sources are compact and thus resemble compact steep-spectrum (CSS) or gigahertz-peaked spectrum (GPS) sources. Images of two representative FIRluminous radio-excess galaxies are analyzed. Their morphologies appear disrupted and do not resemble typical CSS/GPS sources with symmetric double lobes. Synchrotron cooling timescales are derived for several sources and are found to be P10 6 yr. The jet energy fluxes inferred are 10 36 -10 37 W, an order of magnitude lower than typical radio-loud CSS/GPS sources. A dynamical model of a jet-fed lobe is used to derive ages $10 4 yr and jet energy fluxes of $10 37 W for the sources observed with VLBI. Expansion velocities less than 0.01c are derived for the lobes using this model. Thus, the ages of the FIR-luminous radio-excess galaxies are similar to young radio-loud sources, but the jet energy fluxes and expansion velocities are significantly lower than CSS/GPS sources. We conclude that the lower jet energy fluxes are responsible for their observed weaker radio powers when compared with CSS/GPS sources. We do not expect that the radio-excess sources will evolve into classical radio galaxies in the manner envisaged for CSS/GPS sources.

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“…A negative radio power evolution is indeed expected for active radio radio sources (cf. Kaiser et al 1997;Blundell et al 1999). On the other hand, the observed effect can also be caused if a substantial fraction of the GRGs stop their radio activity (and "fade") before they reach a size of 3 Mpc.…”

Section: The 2-mpc Linear Size Cut-offmentioning

confidence: 99%

“…Kaiser et al 1997;Blundell et al 1999) predict the radio power and linear size evolution of powerful radio sources with time. According to these models, GRGs must be extremely old (i.e.…”

Section: Introductionmentioning

confidence: 99%

A new sample of giant radio galaxies from the WENSS survey

Schoenmakers

Bruyn

Röttgering

et al. 2001

A&A

116

141

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Abstract.We have used the Westerbork Northern Sky Survey (WENSS) to define a sample of 47 low redshift (z < ∼ 0.4) giant radio galaxies. This is the largest sample yet of such radio sources originating from a single survey. We present radio maps of the newly discovered giants and optical images and spectra of their host galaxies. We present some of their properties and discuss the selection effects. We investigate the distribution of the sources in the radio power -linear size P−D diagram, and how these parameters relate to the redshifts of the sources in our sample. We find a strong drop in the number of sources with a linear size above 2 Mpc. We argue that this is not a result of selection effects, but that it indicates either a strong luminosity evolution of radio sources of such a size, or that a large fraction of radio sources "switch off" before they are able to grow to a size of 2 Mpc.

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The Nature and Evolution of Classical Double Radio Sources from Complete Samples

Cited by 300 publications

References 122 publications

Jet propagation and the asymmetries of CSS radio sources

Jet propagation and the asymmetries of CSS radio sources

Radio-ExcessIRASGalaxies. III. Radio Properties

A new sample of giant radio galaxies from the WENSS survey

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