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

closest to themclosest to themDara NormanDara Norman

NOAO/CTIONOAO/CTIO

2006 November 6-8 Boston

Collaborators: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

MotivationMotivation

Hierarchical structure formation scenarios may provide a framework for: the evolution of galaxy clusters the growth of black holes the triggering of quasar activityThere is a wealth of evidence There is a wealth of evidence that AGN know about the that AGN know about the larger scale environment.larger scale environment.

The Cluster AGN Environment: Clues to The Cluster AGN Environment: Clues to Formation/EvolutionFormation/Evolution

Black Holes know about their host galaxies

Black hole Black hole mass/velocity mass/velocity dispersion dispersion show a show a correlationcorrelation

e.g. Ferrarese & e.g. Ferrarese & Merritt, 2000Merritt, 2000

Gebhardt et al., Gebhardt et al., 20002000

Bla c k H

o le Ma s s (M

su n )

Velocity Dispersion (kms-1)

AGN know about their neighbors

Evidence of Evidence of mergers in host mergers in host galaxiesgalaxies

e.g. Hutchings, et al. 2002e.g. Hutchings, et al. 2002

Quasars know about Large Scale Structure

(?)

N-body simulations N-body simulations with toy models of with toy models of quasar formation quasar formation can re-produce B-can re-produce B-band quasar band quasar luminosity functionluminosity function

e.g. Kauffmann & Haehnelt, e.g. Kauffmann & Haehnelt, 20002000

Survey of AGN in DLS ClustersSurvey of AGN in DLS Clusters

Main Goals:Main Goals: Determine if AGN triggering and Determine if AGN triggering and

evolution is influenced by the cluster evolution is influenced by the cluster environment.environment.

Compare the weak lensing, X-ray gas Compare the weak lensing, X-ray gas and dynamical mass environments of and dynamical mass environments of AGNAGN

Compare the AGN fraction in DLS Compare the AGN fraction in DLS clusters to other samples.clusters to other samples.

Deep Lens SurveyDeep Lens Survey Sample of total mass Sample of total mass

overdensities is overdensities is selected from the selected from the Deep Lens SurveyDeep Lens Survey Five 2º x 2° fieldsFive 2º x 2° fields 3x3 grid of Mosaic 3x3 grid of Mosaic

Fields (35’x35’)Fields (35’x35’) R ~ 26.5R ~ 26.5 ~50 ~50

galaxies/arcmingalaxies/arcmin22 BVRz’ imagingBVRz’ imaging

Main Survey Goals:Main Survey Goals: Measure cosmic Measure cosmic

shear due to large shear due to large scale structuresscale structures

Measure the Measure the cluster mass cluster mass function to z~1function to z~1

dls.physics.ucdavis.edu

DLS Cluster 3

8’

A Unique Cluster SampleA Unique Cluster Sample

The DLS clusters are the only sample of clusters The DLS clusters are the only sample of clusters discovered solely by their mass properties discovered solely by their mass properties through weak gravitational lensing techniques.through weak gravitational lensing techniques.

Lensing provides the only way to measure cluster Lensing provides the only way to measure cluster mass that is not dependent on dynamical state.mass that is not dependent on dynamical state.

Provides an opportunity to identify young and Provides an opportunity to identify young and forming clustersforming clusters

DLS Cluster SampleDLS Cluster Sample 20 shear selected mass overdensities discovered 20 shear selected mass overdensities discovered

to date.to date. Suggests about 8 clusters per sq. deg.Suggests about 8 clusters per sq. deg. DLS sample of clusters DLS sample of clusters

Mass Range = 4x10Mass Range = 4x101313 - 6x10 - 6x1014 14 MM and and

Redshift range of main clusters = 0.19 - 0.68Redshift range of main clusters = 0.19 - 0.68

20’

DLS Clu 2DLS Clu 8

Wittman et al. 2006 ApJ 643 128

DLS Clu 2 DLS Clu 2

DLS overdensities are true X-ray clustersDLS overdensities are true X-ray clusters 8 have Chandra X-ray data (~20 ks) also taken.8 have Chandra X-ray data (~20 ks) also taken. Most show evidence of substructure (mass and X-Most show evidence of substructure (mass and X-

ray), which may indicate merger activity. ray), which may indicate merger activity.

(e.g Motl et al., 2004, Mohr et al., 1993)(e.g Motl et al., 2004, Mohr et al., 1993)

Weak lensing discovered, X-ray Weak lensing discovered, X-ray Confirmed ClustersConfirmed Clusters

X-ray point source distributionX-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.Seen before in optical.Söchting, et al. (2000, Söchting, et al. (2000, 2004)2004)Voronoi tesselation Voronoi tesselation techniquetechnique

Field X-ray point sourcesField 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

R-band matchesR-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

X-ray point source Surface DensityX-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.

X-ray point source Surface DensityX-ray point source Surface Density

Ruderman and Ebeling, 2005

Ruderman & Ebeling,2005 see similar trend for 51 massive clusters in the Massive Cluster Survey.

But only for relaxed galaxies.

X-ray point source Surface DensityX-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?

Need for spectroscopic data Need for spectroscopic data for point sources and cluster galaxiesfor 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

Future PlansFuture Plans

5 Additional clusters for analysis5 Additional clusters for analysis More DLS color data is now available for More DLS color data is now available for

measuring additional photometric redshiftsmeasuring additional photometric redshifts Applications for 4m time to get redshifts of Applications for 4m time to get redshifts of

brighter sources brighter sources 8m time on young merging cluster galaxies for 8m time on young merging cluster galaxies for

kinematical analysis of these clusters.kinematical analysis of these clusters. Determine the AGN fraction in young and Determine the AGN fraction in young and

merging clusters.merging clusters. Address the possibility of statistical lensing in Address the possibility of statistical lensing in

these clusters.these clusters.

SummarySummary

• 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.