AGN Feedback and Evolution of Radio Sources Discovery of an X-ray Cluster Associated with z.pdf

a r X i v : a s t r o - p h / 0 5 1 1 4 6 4 v 1 1 5 N o v 2 0 0 5 1 AGN FEEDBACK AND EVOLUTION OF RADIO SOURCES: DISCOVERY OF AN X-RAY CLUSTER ASSOCIATED WITH Z=1 QUASAR A. Siemiginowska 1 , C. C. Cheung 2,3 , S.LaMassa 1 , D.Burke 1 , T.L.Aldcroft 1 , J.Bechtold 4 , M.Elvis 1 , and D.M.Worrall 5 1 Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138, USA 2 Jansky Postdoctoral Fellow; National Radio Astronomy Observatory, USA 3 Kavli Institute for Particle Astrophysics Cosmology Stanford University, Varian Physics, Stanford, CA 94305, USA 4 Steward Observatory, University of Arizona, Tucson, AZ, USA 5 Department of Physics, University of Bristol, Tyndall Ave., Bristol, UK ABSTRACT We report the first significant detection of an X-ray clus- ter associated with a powerful (Lbol ～ 1047 erg sec?1) radio-loud quasar at high redshift (z=1.06). Diffuse X- ray emission is detected out to ～ 120 kpc from the CSS quasar 3C 186. A strong Fe-line emission at the zrest = 1.06 confirms its thermal nature. We find that the CSS radio source is highly overpressured with re- spect to the thermal cluster medium by 2-3 orders of magnitude. This provides direct observational evidence that the radio source is not thermally confined as posited in the “frustrated” scenario for CSS sources. Instead, the radio source may be young and at an early stage of its evolution. This source provides the first detection of the AGN in outburst in the center of a cooling flow cluster. Powerful radio sources are thought to be triggered by the cooling flows. The evidence for the AGN activity and in- termittent outbursts comes from the X-ray morphology of low redshift clusters, which usually do not harbour quasars. 3C186 is a young active radio source which can supply the energy into the cluster and potentially prevent its cooling. We discuss energetics related to the quasar activity and the cluster cooling flow, and possible feed- back between the evolving radio source and t