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The largescale, hot gas environments of radioloud AGN
Judith Ineson
Judith Croston, University of Southampton, UK MarBn Hardcastle, University of HerDordshire, UK MaE Jarvis, University of Oxford, UK Ralph KraI, Daniel Evans, HarvardSmithsonian Center for Astrophysics, USA


The problem

G

GiM et al. 2012


· FRI/FRII

Differences in cluster environments of radio galaxies
­ Local FRIs tend to be in richer environments than FRIIs (eg Hine & Longair, 1979) ­ Higher redshiI FRIIs occur in wider range of environments (eg Hill & Lilly, 1991) ­ Examples of both types at all richness extremes ­ HERGs tend to be in poor environments while LERGs occur across a wide range (eg Best, 2004; Hardcastle 2004; Gendre et al. 2013) ­ QSOs/HERGs tend to be in richer environments at higher redshiIs (eg Harvanek et al, 2001; Belsole et al. 2007) ­ At low redshiIs, radio luminosity correlates with cluster richness for LERGs but not HERGs (eg Best, 2004) ­ At higher redshiIs, radio luminosity correlates with cluster richness for QSOs (eg Wold et al. 2000; Falder et al, 2001)

· HERG/LERG


Challenges in studying radio galaxy environments
· Sample bias · Disentangling evoluBon · Subsample selecBon
­ FRI/FRII vs HERGs/LERGs

· Measures of cluster richness

McLure et al, 2004


The ERA programme
· Outstanding quesBons
­ Is radio luminosity related to environment richness? ­ Does the relaBonship between radio properBes and environment evolve?
· Radio luminosity/morphology/spectrum

· Chandra/XMM large project: Environments of Radioloud AGN (ERA)
­ Examine radio luminosity vs Xray cluster environment at a single redshi, ­ Compare this with results across different redshiIs


ERA sample
McLure et al (2004) ZP5 sample ERA sample


Examples
3C 427.1 3C 274.1

LERG L151 = 339x1025 WHz1sr1 RedshiI = 0.572

R500 = 620 kpc Lx = 26.2x1043 erg.s1 Temperature = 3.1 keV

HERG L151 = 105x1025 WHz1sr1 RedshiI = 0.422

R500 = 343 kpc Lx = 3.66x1043 erg.s1 Temperature = 0.95 keV

TO 1255

7C 1731

LERG L151 = 1.02x1025 WHz1sr1 RedshiI = 0.471

R500 = 351 kpc Lx = 0.48x1043 erg.s1 Temperature = 1.0 keV

HERG L151 = 4.17x1025 WHz1sr1 RedshiI = 0.562

R500 Lx = <2.97x1043 erg.s1 Temperature


ERA sample results
Kendall Tau tests All data p < 0.005 HERG N/S LERG p < 0.008

· CorrelaBon between radio luminosity and cluster richness · CorrelaBon driven by LERGs · Reflects results across wider redshiI ranges
Ineson et al, 2013

­ Eg Best 2004; Wold et al. 2000; Falder et al. 2010


Preliminary comparison sample
· z < 0.03
­ Croston et al. (2008)

· 0.1 < z < 0.5
­ Shelton MSc thesis(2011)

· 0.45 < z < 1.0
­ Belsole et al. (2007)


Preliminary comparison results

· Full sample and LERG subsample environments correlate with radio luminosity ­ StaBsBcally significant in presence of common correlaBon with redshiI (ParBal Kendall Tau, p<0.0001) · HERG subsample does not correlate with redshiI


Low redshiI comparison sample
· 0.01 < z < 0.1 · All 3CRR sources · Xray analysis on going · High z/high LR to follow


Summary
· Looked at cluster richness for a unique sample of radio galaxies at z ~ 0.5 spanning 3 decades in LR · CorrelaBon between radio luminosity and the cluster richness of radio galaxies
­ ScaEer may be an indicaBon of other factors ­ Evidence tentaBve as yet

· CorrelaBon appears to be driven by LERG sub populaBon · Preliminary indicaBons that the correlaBon applies at other epochs
­ Preparing a lowz comparison sample