Weak-Lensing selected, X-ray confirmed Clusters and the AGN closest to them

1. Weak-Lensing selected, X-ray confirmed Clusters and the AGN closest to them Collaborators: Deep Lens Survey Team: David Wittman, Tony Tyson, Vera Margoniner - UC Davis, Jack Hughes - Rutgers U. , Ian Dellantonio - Brown U. Recent additions: Ilona Soechting - University of Oxford, Percy Gomez - Gemini Dara Norman NOAO/CTIO 2006 November 6-8 Boston

2. Motivation The Cluster AGN Environment: Clues to Formation/Evolution Hierarchical structure formation scenarios may provide a framework for: • the evolution of galaxy clusters • the growth of black holes • the triggering of quasar activity There is a wealth of evidence that AGN know about the larger scale environment.

3. Black hole mass/velocity dispersion show a correlation e.g. Ferrarese & Merritt, 2000 Gebhardt et al., 2000 Black Holes know about their host galaxies Black Hole Mass (Msun) Velocity Dispersion (kms-1)

4. Evidence of mergers in host galaxies e.g. Hutchings, et al. 2002 AGN know about their neighbors

5. N-body simulations with toy models of quasar formation can re-produce B-band quasar luminosity function e.g. Kauffmann & Haehnelt, 2000 Quasars know about Large Scale Structure (?)

6. Survey of AGN in DLS Clusters Main Goals: • Determine if AGN triggering and evolution is influenced by the cluster environment. • Compare the weak lensing, X-ray gas and dynamical mass environments of AGN • Compare the AGN fraction in DLS clusters to other samples.

7. Deep Lens Survey DLS Cluster 3 • Sample of total mass overdensities is selected from the Deep Lens Survey • Five 2º x 2° fields • 3x3 grid of Mosaic Fields (35’x35’) • R ~ 26.5 • ~50 galaxies/arcmin2 • BVRz’ imaging • Main Survey Goals: • Measure cosmic shear due to large scale structures • Measure the cluster mass function to z~1 8’ dls.physics.ucdavis.edu

8. A Unique Cluster Sample • The DLS clusters are the only sample of clusters discovered solely by their mass properties through weak gravitational lensing techniques. • Lensing provides the only way to measure cluster mass that is not dependent on dynamical state. • Provides an opportunity to identify young and forming clusters

9. DLS Cluster Sample • 20 shear selected mass overdensities discovered to date. • Suggests about 8 clusters per sq. deg. • DLS sample of clusters Mass Range = 4x1013 - 6x1014 M and Redshift range of main clusters = 0.19 - 0.68 DLS Clu 8 DLS Clu 2 20’ Wittman et al. 2006 ApJ 643 128

10. DLS Clu 2 DLS Clu 2 DLS overdensities are true X-ray clusters • 8 have Chandra X-ray data (~20 ks) also taken. • Most show evidence of substructure (mass and X-ray), which may indicate merger activity. (e.g Motl et al., 2004, Mohr et al., 1993)

11. Weak lensing discovered, X-ray Confirmed Clusters

12. X-ray point source distribution • Chandra observations also reveal a large number of X-ray point sources in these cluster fields. • These sources appear to show an aversion to the most massive regions of the cluster. • Seen before in optical. • Söchting, et al. (2000, 2004) • Voronoi tesselation technique

13. Field X-ray point sources 123 X-ray point sources with S/N > 2 in 3 cluster fields Limiting flux is ~ 8 x 10-15 ergs s-1 cm-1 Clusters have redshifts of 0.3, 0.3 and 0.68

14. R-band matches • 68 sources match DLS R band sources to 1.5’’ • R magnitudes = ~16.2 - 26 • Good photmetric redshifts are currently available for 31 sources

15. X-ray point source Surface Density • For all sources in the field X-ray sources show two peaks, • a strong peak in the central 0.25 Mpcs and • a broad peak in surface density at about 1.25 - 1.75 Mpc, true for both z=0.3 and 0.68 clusters.

16. X-ray point source Surface Density Ruderman & Ebeling,2005 see similar trend for 51 massive clusters in the Massive Cluster Survey. But only for relaxed galaxies. Ruderman and Ebeling, 2005

17. X-ray point source Surface Density Several sources are known to be background. Elimination of these and HR < -0.5 increases surface density in the center but keeps the 1.4 Mpc peak. Are these infall regions where AGN activity is triggered?

18. Need for spectroscopic data for point sources and cluster galaxies • Kinematical studies of the cluster galaxies • At these low redshifts, photo-z errors result in mis-identifications of cluster membership. • Statistical gravitational lensing of background sources can be significant for these lower redshift fields. • Background sources can be brighted into a flux limited sample by lensing. • Angular Correlation measures for Radio and Optical AGN show over densities on scales of 0.7-1.0 Mpc at z=0.3 Models from Dolag and Bartelmann, 1997 Norman & Impey, 2000

19. Future Plans • 5 Additional clusters for analysis • More DLS color data is now available for measuring additional photometric redshifts • Applications for 4m time to get redshifts of brighter sources • 8m time on young merging cluster galaxies for kinematical analysis of these clusters. • Determine the AGN fraction in young and merging clusters. • Address the possibility of statistical lensing in these clusters.

20. Summary • DLS cluster sample is the ONLY cluster sample selected by weak lensing shear techniques and is not dependent on cluster dynamical state. • A large number of identified clusters show X-ray substructure. • X-ray point sources in the fields of DLS weak gravitational lensing discovered fields show and aversion to the densest mass distribution as determined by gravitational shear mass maps. Surface density shows peaks in the core and at 1.5 Mpc. • Spectroscopic redshifts for X-ray sources are needed in order to eliminate contamination by background sources. An accurate census of cluster (versus background) AGN is essential to the use of their distribution to understand cluster formation and AGN triggering.