The environments of luminous radio galaxies and type-2 quasars

Almeida, C. Ramos; Bessiere, P. S.; Tadhunter, C. N.; Inskip, K. J.; Morganti, Raffaella; Dicken, D.; González‐Serrano, J. I.; Holt, J.

doi:10.1093/mnras/stt1595

Cited by 60 publications

(120 citation statements)

References 98 publications

(175 reference statements)

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“…We have a hint that there might be at least occasional objects in this region from Ramos Almeida et al (2013) they obtained an extremely low galaxy-quasar spatial covariance function (Bgq) for PKS1136−13, which has a radio luminosity of 2.7 × 10 26 W Hz −1 sr −1 . If this source follows the expected correlation between LX and Bgq, it would then lie well into the lower right portion of the LX − LR plot.…”

Section: Redshift Evolutionmentioning

confidence: 93%

“…Yee & Ellingson 2003;Ledlow et al 2003, I13). Ramos Almeida et al (2013) have calculated the galaxyquasar spatial covariance function (Bgq) for the 2Jy sample. We therefore compared these with the ICM luminosities for the 2Jy sources within our z0.1 sample (Figure 13).…”

Section: Comparison With Optical Measuresmentioning

confidence: 99%

“…PKS 0034−01 (3C 15) is a LERG with small FRII lobes in a weak environment (Bgq ∼ 90 -Ramos Almeida et al 2013). Like Rinn et al (2005), we found insufficient evidence of ICM emission for analysis so we calculated upper limits for the temperature and luminosity.…”

Section: A2 2jy Sourcesmentioning

confidence: 99%

“…PKS 0038+09 (3C 18) is a BLRG with small FRII lobes in a weak environment (Bgq ∼ 35 -Ramos Almeida et al 2013). The short observation time gave us insufficient counts for spectral analysis, so we used an estimated temperature of 1.8 keV.…”

Section: A2 2jy Sourcesmentioning

confidence: 99%

“…There is also some evidence that HERGs occupied richer environments in earlier epochs (e.g. Harvanek et al 2001;Belsole et al 2007;Ramos Almeida et al 2013), suggesting evolution of the large-scale environment; conversely, Wold et al (2000) and McLure & Dunlop (2001) found no evidence of evolution.…”

Section: Introductionmentioning

confidence: 99%

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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: Redshift Evolutionmentioning

confidence: 93%

Section: Comparison With Optical Measuresmentioning

confidence: 99%

Section: A2 2jy Sourcesmentioning

confidence: 99%

Section: A2 2jy Sourcesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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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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Radio AGN in the local universe: unification, triggering and evolution

Tadhunter

2016

Astron Astrophys Rev

149

150

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Associated with one of the most important forms of active galactic nucleus (AGN) feedback, and showing a strong preference for giant elliptical host galaxies, radio AGN (L_1.4GHz > 10^24 W Hz^-1) are a key sub-class of the overall AGN population. Here I review our current state of understanding of the population of radio AGN at low and intermediate redshifts (z < 0.7), concentrating on their AGN and host galaxy properties, and covering three interlocking themes: the classification of radio AGN and its interpretation; the triggering and fuelling of the jet and AGN activity; and the evolution of the host galaxies. I show that much of the observed diversity in the AGN properties of radio AGN can be explained in terms of a combination of orientation/anisotropy, mass accretion rate, and variability effects. The detailed morphologies of the host galaxies are consistent with the triggering of strong-line radio galaxies (SLRG) in galaxy mergers. However, the star formation properties and cool ISM contents suggest that the triggering mergers are relatively minor in terms of their gas masses in most cases, and would not lead to major growth of the supermassive black holes and stellar bulges; therefore, apart from a minority (<20%) that show evidence for higher star formation rates and more massive cool ISM reservoirs, the SLRG represent late-time re-triggering of activity in mature giant elliptical galaxies. In contrast, the host and environmental properties of weak-line radio galaxies (WLRG) with Fanaroff-Riley class I (FRI) radio morphologies are consistent with more gradual fuelling of the activity via gas accretion at low rates onto the supermassive black holes.Comment: Accepted for publication in Astronomy & Astrophysics Review, 67 pages, 17 figure

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