Observed properties of FRII quasars and radio galaxies at<i>z</i>&lt; 1.0

Mullin, L. M.; Riley, J. M.; Hardcastle, M. J.

doi:10.1111/j.1365-2966.2008.13534.x

Cited by 88 publications

(127 citation statements)

References 63 publications

(73 reference statements)

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“…de Ruiter et al (1990) show that the core prominence in the B2 sample (Colla et al 1970, Fanti et al 1978) is inversely proportional to the radio luminosity of the source varying in the range 0.1-0.001 for radio powers in the range 10 24 − 10 26 WHz −1 . In agreement with this finding, the objects in the 3CRR sample, which contains the most powerful radio galaxies in the sky, show a mean radio core prominence of ∼3×10 −4 (Giovannini et al 1988, Mullin et al 2008. We therefore expect remnant radio galaxies to have, on average, a CP ×10 −4 .…”

Section: Low Radio Core Prominence Selectionsupporting

confidence: 65%

Search and modelling of remnant radio galaxies in the LOFAR Lockman Hole field

Brienza

Godfrey

Morganti

et al. 2017

A&A

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178

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Context. The phase of radio galaxy evolution after the jets have switched off, often referred to as the remnant phase, is poorly understood and very few sources in this phase are known. Aims. In this work we present an extensive search for remnant radio galaxies in the Lockman Hole, a well-studied extragalactic field. We create mock catalogues of low-power radio galaxies based on Monte Carlo simulations to derive first-order predictions of the fraction of remnants in radio flux limited samples for comparison with our Lockman-Hole sample. Methods. Our search for remnant radio galaxies is based on LOFAR observations at 150 MHz combined with public survey data at higher frequencies. To enhance the selection process, and obtain a more complete picture of the remnant population, we use spectral criteria such as ultra-steep spectral index and high spectral curvature, and morphological criteria such as low radio core prominence and relaxed shapes to identify candidate remnant radio galaxies. Mock catalogues of radio galaxies are created based on existing spectral and dynamical evolution models combined with observed source properties. Results. We have identified 23 candidate remnant radio galaxies which cover a variety of morphologies and spectral characteristics. We suggest that these different properties are related to different stages of the remnant evolution. We find that ultra-steep spectrum remnants represent only a fraction of our remnant sample suggesting a very rapid luminosity evolution of the radio plasma. Results from mock catalogues demonstrate the importance of dynamical evolution in the remnant phase of low-power radio galaxies to obtain fractions of remnant sources consistent with our observations. Moreover, these results confirm that ultra-steep spectrum remnants represent only a small subset of the entire population (∼50%) when frequencies higher than 1400 MHz are not included in the selection process, and that they are biased towards old ages.

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Section: Low Radio Core Prominence Selectionsupporting

confidence: 65%

Search and modelling of remnant radio galaxies in the LOFAR Lockman Hole field

Brienza

Godfrey

Morganti

et al. 2017

A&A

Self Cite

178

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“…As a result, the jet power calculated from the lobe radio luminosity represents a measure of the time-averaged jet power. The hotspot luminosity may vary on short timescales due to variation in jet power, but the hotspots typically contribute only a small fraction of the total radio luminosity (Mullin et al 2008), and so the integrated lobe luminosity will not be significantly affected by short timescale variation in the jet power. In contrast, the disc luminosity is a measure of instantaneous accretion rate, and the accretion rate may vary significantly on timescales much shorter than the lifetime of the radio galaxy.…”

Section: Discussionmentioning

confidence: 99%

On the efficiency of jet production in FR II radio galaxies and quasars

Rusinek

Sikora

Kozieł-Wierzbowska

et al. 2016

Mon. Not. R. Astron. Soc.

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Jet powers in many radio galaxies with extended radio structures appear to exceed their associated accretion luminosities. In systems with very low accretion rates, this is likely due to the very low accretion luminosities resulting from radiatively inefficient accretion flows. In systems with high accretion rates, the accretion flows are expected to be radiatively efficient, and the production of such powerful jets may require an accretion scenario which involves magnetically arrested discs (MADs). However, numerical simulations of the MAD scenario indicate that jet production efficiency is large only for geometrically thick accretion flows and scales roughly with (H/R) 2 , where H is the disc height and R is the distance from the BH. Using samples of FR II radio galaxies and quasars accreting at moderate accretion rates we show that their jets are much more powerful than predicted by the MAD scenario. We discuss possible origins of this discrepancy, suggesting that it can be related to approximations adopted in MHD simulations to treat optically thick accretion flow within the MAD-zone, or may indicate that accretion disks are geometrically thicker than the standard theory predicts.

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“…Each object includes the measured 178 MHz radio lobe luminosity, R-band optical magnitude (for approximately three quarters of the sample), and the largest linear source size, width and axis ratio of each lobe. The Mullin et al (2008) dataset is compiled from the complete flux-limited sample of Laing et al (1983) which includes all 3C sources with total 178 MHz flux densities S 178 > 10.9 Jy. These 3C galaxies are further cross-matched with K-band near-infrared magnitudes and multi-frequency radio observations to enable estimation of the host stellar mass and fitting of the spectral curvature respectively.…”

Section: Powerful Radio Agn Samplementioning

confidence: 99%

RAiSE III: 3C radio AGN energetics and composition

Turner

Shabala

Krause

2017

Monthly Notices of the Royal Astronomical Society

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Kinetic jet power estimates based exclusively on observed monochromatic radio luminosities are highly uncertain due to confounding variables and a lack of knowledge about some aspects of the physics of active galactic nuclei (AGNs). We propose a new methodology to calculate the jet powers of the largest, most powerful radio sources based on combinations of their size, lobe luminosity and shape of their radio spectrum; this approach avoids the uncertainties encountered by previous relationships. The outputs of our model are calibrated using hydrodynamical simulations and tested against independent X-ray inverse-Compton measurements. The jet powers and lobe magnetic field strengths of radio sources are found to be recovered using solely the lobe luminosity and spectral curvature, enabling the intrinsic properties of unresolved highredshift sources to be inferred. By contrast, the radio source ages cannot be estimated without knowledge of the lobe volumes. The monochromatic lobe luminosity alone is incapable of accurately estimating the jet power or source age without knowledge of the lobe magnetic field strength and size respectively. We find that, on average, the lobes of the 3C radio sources have magnetic field strengths approximately a factor three lower than the equipartition value, inconsistent with equal energy in the particles and the fields at the 5σ level. The particle content of 3C radio lobes is discussed in the context of complementary observations; we do not find evidence favouring an energetically-dominant proton population.

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Observed properties of FRII quasars and radio galaxies atz< 1.0

Cited by 88 publications

References 63 publications

Search and modelling of remnant radio galaxies in the LOFAR Lockman Hole field

Search and modelling of remnant radio galaxies in the LOFAR Lockman Hole field

On the efficiency of jet production in FR II radio galaxies and quasars

RAiSE III: 3C radio AGN energetics and composition

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