The Evolution of Extragalactic Radio Sources

Luo, Quantian; Sadler, E. M.

doi:10.1088/0004-637x/713/1/398

Cited by 25 publications

(43 citation statements)

References 26 publications

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“…For the jet power probability distribution we assume a power-law distribution with slope δ = 0.6 (Willott et al 2001 andKaiser &Best 2007) in the range 10 34 − 5 × 10 37 W (Luo & Sadler 2010).…”

Section: Jet Power Q Jetmentioning

confidence: 99%

“…In the active phase we assume that the expansion of the source is driven by the jet, according to the pressure-limiting expansion model presented in Luo & Sadler (2010). This considers that as the source expands the internal lobe pressure continuously finds a balance with the external pressure that decreases outwardly.…”

Section: Simulation With Radiative and Dynamical Evolutionmentioning

confidence: 99%

“…The proportionality is justified because the model does not depend on the absolute volume value, but only on its variations over time. Similarly, the magnetic energy density B, which is assumed to be coupled with the plasma, evolves with time following a piece-wise power law whose power depends on the surrounding environment and on the source age as B(t) = B 0 t −2β/(3−β) , i f t < t on (Luo & Sadler 2010)…”

Section: Simulation With Radiative and Dynamical Evolutionmentioning

confidence: 99%

“…4.2. As a first-order approximation, we keep the value of the power exponent β fixed to 1.5 for all galaxies (Luo & Sadler 2010, Morganti et al 1988). …”

Section: Radial Density Profile Exponent βmentioning

confidence: 99%

“…We assume here that the electron-to-proton ratio is k=1 as suggested by Croston (2008) for lobed FRIs. Here we assume that at an initial time, t 0 = 0.1 Myr, each source has a size which depends on its jet power and the ambient medium according to equation (4) of Luo & Sadler (2010). As we are using a pressure-limiting expansion with p lobe ∼ p amb , we can derive the internal lobe pressure as…”

Section: Initial Magnetic Energy Density Bmentioning

confidence: 99%

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

Brienza

Godfrey

Morganti

et al. 2017

A&A

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: Jet Power Q Jetmentioning

confidence: 99%

Section: Simulation With Radiative and Dynamical Evolutionmentioning

confidence: 99%

Section: Simulation With Radiative and Dynamical Evolutionmentioning

confidence: 99%

“…4.2. As a first-order approximation, we keep the value of the power exponent β fixed to 1.5 for all galaxies (Luo & Sadler 2010, Morganti et al 1988). …”

Section: Radial Density Profile Exponent βmentioning

confidence: 99%

Section: Initial Magnetic Energy Density Bmentioning

confidence: 99%

See 3 more Smart Citations

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

Brienza

Godfrey

Morganti

et al. 2017

A&A

178

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Fundamental parameters of FR II radio galaxies and their impact on groups and clusters' environments

Kapińska¹,

Uttley²

2013

Astron Nachr

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Radio galaxies are among the largest and most powerful single objects known and are found at variety of redshifts, hence they are believed to have had a significant impact on the evolving Universe. Their relativistic jets inject considerable amounts of energy into the environments in which the sources reside; thus the knowledge of the fundamental properties (such as kinetic luminosities, lifetimes and ambient gas densities) of these sources is crucial for understanding AGN feedback in galaxy clusters. In this work, we explore the intrinsic and extrinsic fundamental properties of Fanaroff-Riley II (FR II) objects through the construction of multidimensional Monte Carlo simulations which use complete, flux limited radio catalogues and semi-analytical models of FR IIs' time evolution to create artificial samples of radio galaxies. This method allows us to set better limits on the confidence intervals of the intrinsic and extrinsic fundamental parameters and to investigate the total energy produced and injected to the clusters' environments by populations of FR IIs at various cosmological epochs (0.0 < z < 2.0). We find the latter estimates to be strikingly robust despite the strong degeneracy between the fundamental parameters -such a result points to a conclusive indicator of the scale of AGN feedback in clusters of galaxies.

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