Bright radio sources at 178 MHz: flux densities, optical identifications and the cosmological evolution of powerful radio galaxies

Laing, R. A.; Riley, J. M.; Longair, M. S.

doi:10.1093/mnras/204.1.151

Cited by 702 publications

(659 citation statements)

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“…The new sample, hereafter referred to as the z0.1 sample, consists of all radio-loud AGN with visible structure beyond the nucleus lying in the redshift range 0.01 z 0.2 from two flux-limited radio surveys: the 3CRR survey (Laing et al 1983) and the subsample of the 2Jy survey (Wall & Peacock 1985;Tadhunter et al 1993) defined by Dicken et al (2008). The initial sample contained 38 3CRR and 22 2Jy sources, but five sources were excluded.…”

Section: The Samplementioning

confidence: 99%

The link between accretion mode and environment in radio-loud active galaxies

Ineson

Croston

Hardcastle

et al. 2015

Mon. Not. R. Astron. Soc.

130

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The interactions between radio-loud AGN and their environments play an important rôle in galaxy and cluster evolution. Recent work has demonstrated fundamental differences between High and Low Excitation Radio Galaxies (HERGs and LERGs), and shown that they may have different relationships with their environments. In the Chandra Large Project ERA (Environments of Radio-loud AGN), we made the first systematic X-ray environmental study of the cluster environments of radio galaxies at a single epoch (z ∼ 0.5), and found tentative evidence for a correlation between radio luminosity and cluster X-ray luminosity. We also found that this relationship appeared to be driven by the LERG sub-population (Ineson et al. 2013).We have now repeated the analysis with a low redshift sample (z ∼ 0.1), and found strong correlations between radio luminosity and environment richness and between radio luminosity and central density for the LERGs but not for the HERGs. These results are consistent with models in which the HERGs are fuelled from accretion discs maintained from local reservoirs of gas, while LERGs are fuelled more directly by gas ingested from the intra-cluster medium.Comparing the samples, we found that although the maximum environment richness of the HERG environments is similar in both samples, there are poorer HERG environments in the z ∼ 0.1 sample than in the z ∼ 0.5 sample. We have therefore tentative evidence of evolution of the HERG environments. We found no differences between the LERG subsamples for the two epochs, as would be expected if radio and cluster luminosity are related.

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Section: The Samplementioning

confidence: 99%

The link between accretion mode and environment in radio-loud active galaxies

Ineson

Croston

Hardcastle

et al. 2015

Mon. Not. R. Astron. Soc.

130

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“…Therefore, the RLQs are selected based on optically thin extended emission, which means that the sample selection should be largely orientation independent. The RGs were selected from the low frequency, (178 or 151 MHz; orientation independent) radio samples of the 3CRR (Laing et al 1983), 6CE (Eales 1985), 7CRS (Willott et al 1998) and TOOT surveys (Hill & Rawlings 2003). For the 6C objects the redshifts are taken from Best et al (1996), Rawlings et al (2001) and Inskip et al (2005), and for the 6C* and TOOT objects from Jarvis et al (2001b) and Vardoulaki et al (2010), respectively.…”

Section: Sample Selectionmentioning

confidence: 99%

Observational evidence that positive and negative AGN feedback depends on galaxy mass and jet power

Kalfountzou

Stevens

Jarvis

et al. 2017

Monthly Notices of the Royal Astronomical Society

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Several studies support the existence of a link between the AGN and star formation activity. Radio jets have been argued to be an ideal mechanism for direct interaction between the AGN and the host galaxy. A drawback of previous surveys of AGN is that they are fundamentally limited by the degeneracy between redshift and luminosity in flux-density limited samples. To overcome this limitation, we present far-infrared Herschel observations of 74 radio-loud quasars (RLQs), 72 radio-quiet quasars (RQQs) and 27 radio galaxies (RGs), selected at 0.9 < z < 1.1 which span over two decades in optical luminosity. By decoupling luminosity from evolutionary effects, we investigate how the star formation rate (SFR) depends on AGN luminosity, radio-loudness and orientation. We find that: 1) the SFR shows a weak correlation with the bolometric luminosity for all AGN sub-samples, 2) the RLQs show a SFR excess of about a factor of 1.4 compared to the RQQs, matched in terms of black hole mass and bolometric luminosity, suggesting that either positive radio-jet feedback or radio AGN triggering are linked to star-formation triggering and 3) RGs have lower SFRs by a factor of 2.5 than the RLQ sub-sample with the same BH mass and bolometric luminosity. We suggest that there is some jet power threshold at which radio-jet feedback switches from enhancing star formation (by compressing gas) to suppressing it (by ejecting gas). This threshold depends on both galaxy mass and jet power.

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“…These are upper limits only in the sense that there is an unknown contribution from non-thermal emission. All of these sources (except 3C 236) have weak radio cores, so that from the observed correlation between radio and X-ray nuclear emission (paper I) we would Redshifts are taken from Laing et al (1983). An H in column 3 indicates that the data come from the ROSAT HRI; a P indicates the PSPC.…”

Section: X-ray Uncertaintiesmentioning

confidence: 99%

The environments of FRII radio sources

Hardcastle

Worrall

2000

Monthly Notices of the Royal Astronomical Society

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Using ROSAT observations, we estimate gas pressures in the X-ray-emitting medium surrounding 63 FRII radio galaxies and quasars. We compare these pressures with the internal pressures of the radio-emitting plasma estimated by assuming minimum energy or equipartition. In the majority of cases (including 12/13 sources with modelled, spatially resolved X-ray emission) radio sources appear to be underpressured with respect to the external medium, suggesting that simple minimum-energy arguments underestimate the sources' internal energy density. We discuss possible departures from the minimum energy condition and the consequences of our result for models of the dynamics of radio galaxies, in particular self-similar models (Kaiser & Alexander 1997).

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Bright radio sources at 178 MHz: flux densities, optical identifications and the cosmological evolution of powerful radio galaxies

Cited by 702 publications

References 0 publications

The link between accretion mode and environment in radio-loud active galaxies

The link between accretion mode and environment in radio-loud active galaxies

Observational evidence that positive and negative AGN feedback depends on galaxy mass and jet power

The environments of FRII radio sources

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