24-28 October 2005 Elena Belsole University of Bristol Distant clusters of Galaxies Ringberg Workshop X-ray constraints on cluster-scale emission around high-redshift radio galaxies Elena Belsole in collaboration with D. Worrall & M. Hardcastle

24-28 October 2005 Elena Belsole University of Bristol Distant clusters of Galaxies Ringberg Workshop Outline Introduction Theory for jet confinement Environment expected from radio observations and minimum energy condition What was the situation with ROSAT Observational situation: An example: Two sources observed with XMM The new picture from Chandra and XMM Conclusions Future prospects

24-28 October 2005 Elena Belsole University of Bristol Distant clusters of Galaxies Ringberg Workshop Introduction Powerful (P 178 Mhz > W Hz -1 sr -1 ) radio sources are visible at high redshift Sources classified as FRII have a double sided jet which terminates in hotspots sometimes at distances of ~ 1Mpc Jet propagation and termination require a gaseous environment for confinement (standard beam- model, Begelman et al. 84) X-ray emission traces the hot gas component. Powerful radio galaxies are possible tracers of galaxy groups and clusters

24-28 October 2005 Elena Belsole University of Bristol Distant clusters of Galaxies Ringberg Workshop Introduction Advantages: Radio selection: not biased towards luminous clusters (unlike X- ray flux limited samples) Radio observations can be used alone to estimate the external gas density, if minimum energy condition applies, : ρ ∝ (B/v L ) 2 – ram pressure confinement eq. Easier than SZ for these sources Disadvantages In X-ray: component separation and sensitivity (low SB objects) Not many active radio sources; are we looking at a particular class of object?

24-28 October 2005 Elena Belsole University of Bristol Distant clusters of Galaxies Ringberg Workshop Observational framework Most powerful radio sources are at high redshift By analogy to low-z sources (Cygnus A) minimum energy condition is assumed (e.g. Wellman et al. 97) These studies predict clusters with ICM densities comparable to low-z clusters and similar shape. ROSAT observations: Evidence difficult to obtain for external environment around RGs and QSO at z>0.5 [Worrall et al. 94, Crawford & Fabian 96, Hardcastle & Worrall 99, Crawford et al. 99] Question is still open

24-28 October 2005 Elena Belsole University of Bristol Distant clusters of Galaxies Ringberg Workshop Observational status: the new generation X-ray satellites

24-28 October 2005 Elena Belsole University of Bristol Distant clusters of Galaxies Ringberg Workshop 3C292 z=0.71 XMM exposure time: 20 ks Belsole et al. 2004

24-28 October 2005 Elena Belsole University of Bristol Distant clusters of Galaxies Ringberg Workshop Lobes Unabsorbed power law  =1.9±0.3 Flux (1 keV) = 4 nJy Total IC flux 2.4 nJy Environment β=0.8, r c – 19.7 arcsec kT = keV L X (bol)= erg/s 3C292

24-28 October 2005 Elena Belsole University of Bristol Distant clusters of Galaxies Ringberg Workshop 3C184z:0.994 XMM/EPIC image 54 ks (MOS) 16 ks (pn) Belsole et al. 2004

24-28 October 2005 Elena Belsole University of Bristol Distant clusters of Galaxies Ringberg Workshop Point source +  model  = 0.66, r c = 200 kpc evidence of extended emission L X ~ 5.9 x X-ray spectrum: 3 components  S = 1.5±1.0 from Chandra N H = cm -2 ;  H = 1.4±0.35 kT = keV; L X = 8.3±1.8 x erg/s 3C184

24-28 October 2005 Elena Belsole University of Bristol Distant clusters of Galaxies Ringberg Workshop HST (Deltorn et al. 97) Excess of galaxies + 11 galaxies at z~1 Arc detection and mass within arc ~2 x M sun 3C184 Chandra images and 5 GHz radio contours the pressure of the external medium is a factor of 20 lower than the minimum internal pressure of the galaxy ==> the galaxy is expanding

24-28 October 2005 Elena Belsole University of Bristol Distant clusters of Galaxies Ringberg Workshop Observational status: summary of current results FRII in the 3CRR and with 0.5<z<1.0 [Donahue et al. 03; Crawford & Fabian 03; Hardcastle et al 02; Brunetti et al. 02] Only 3 objects have measured X-ray temperature: 3C220.1T~ 5.6 keV(Worrall et al. 2003) 3C184T~3.5 keV (Belsole et al. 2004) 3C292T~2.2 keV (Belsole et al. 2004) Luminosities are easier to estimate

24-28 October 2005 Elena Belsole University of Bristol Distant clusters of Galaxies Ringberg Workshop Bolometric L X (10 43 erg/s) N

24-28 October 2005 Elena Belsole University of Bristol Distant clusters of Galaxies Ringberg Workshop Observational status: summary of current results FRII in the 3CRR and with z>0.5 [Donahue et al. 03; Crawford & Fabian 03; Hardcastle et al 02; Brunetti et al. 02] Only 3 objects have measured X-ray temperature: 3C220.1T~ 5.6 keV(Worrall et al. 2003) 3C184T~3.5 keV (Belsole et al. 2004) 3C292T~2.2 keV (Belsole et al. 2004) Luminosities are easier to estimate … and largely found to be ~ erg/s kT ~ keV Extended emission associated with lobes (IC) and hotspots (IC - SSC - Syn)

24-28 October 2005 Elena Belsole University of Bristol Distant clusters of Galaxies Ringberg Workshop Conclusions Detection of diffuse emission from most of the radio sources at z>0.5 Most of the extended emission is radio related X-ray environment mostly of poor clusters (with few exceptions) but sufficient to confine the lobes FRII radio galaxies are tracers of a broad range of environments ? IF yes they provide an unbiased sample of the structures in the Universe caveat It is difficult to separate components!

24-28 October 2005 Elena Belsole University of Bristol Distant clusters of Galaxies Ringberg Workshop Future prospects Quantitative investigation of the X-ray environment.... In progress (see Belsole et al. 2005, MNRAS, sub; Belsole et al. 2006, in prep.) Comparison with lobe internal pressure (see also Croston et al. 2005) ; is the minimum energy condition satisfied? Comparison with lower redshift sources: evolution?