XRay Observations of RCS Clusters at High Redshift

X-Ray Observations of RCS Clusters at High Redshift Erica Ellingson, U. Colorado Amalia Hicks, U. Colorado/ U. Virginia Mark Bautz, MIT Henk Hoekstra (U. Victoria) Mike Gladders, Carnegie Obs. Howard Yee, U. Toronto

The RCS Surveys Review by H. Yee earlier today: optically selected clusters via their red sequence RCS-1; 90 square degrees (completed) RCS-2: 1000 square degrees Z~1 Still needed: calibration of cluster mass estimates for optically selected clusters

RCS Chandra Observations Chosen from the sample: 9 clusters (now 12) (0. 64) 0. 75< z< 1. 1 Some initial emphasis on the most massive, lensing systems from the first available RCS catalogs; sample is becoming representative of rich systems ACIS exposures: (10) 30 -90 Ksec

Optical/Chandra Observations Z=0. 78 Z=0. 64

z=1. 0 8 out of 9 detected with > 5 (2112 -6326 at zph=1. 1 is 2 -3 ) 3 additional cluster detections on the way (final data arrived this week)

20 ksec first exposure (more just arrived): Three new detections: z ~ 0. 6 -0. 9

“Low Redshift” Comparisons 14 X-Ray selected CNOC (EMSS + Abell 2390) 0. 17 < z < 0. 55 Well determined masses via dynamics, lensing, Xrays (ROSAT +Chandra) Carlberg, Yee & Ellingson 1997 van der Marel et al. 2000 Lewis et al. 1999 Hicks et al. 2005

Lensing Masses for CNOC Weak lensing comparisons at z=0. 2 -0. 55 (with Henk Hoekstra) Slight systematic mass overestimate (10%) for weak lensing masses

Calibrating Optical Richness with X-ray properties Initial mass estimator for RCS is the optical richness from the survey data: Bgc CNOC: Good agreement with expected relationships: Bgc vs. , Lx, Tx, M 200 Yee & Ellingson 2003, updated for Chandra by Hicks, et al. , 2005 Black: weak lensing shear composites (Hoekstra) Red: CNOC cluster dynamics

RCS: Lx-Bgc RCS clusters are under-luminous for their optical richness See also: Donahue et al. 99, Gilbank, 2004 Lubin et al. , 2004 … L 2500 CNOC, CF corrected : diamonds RCS: squares

Tx-Bgc Temperatures show general agreement with lower-z X -ray samples Slightly systematically lower temperature for their optical richnesses Outlier: superposition of groups in small z range (e. g. , Gilbank’s talk, also Gonzales’ supergroup? ): predicted to be ~5% of RCS? Diamonds= CNOC Squares = 6 RCS clusters with enough signal to measure Tx

RCS: clusters underluminous for expected Tx? Large uncertainties… Lx-Tx Solid: slope=2. 2 Dotted = 2. 0 Dashed= best fit slope 4+/- 2 See also Lubin, et al. , 2004 CNOC: diamonds RCS: squares

Redshift Evolution of Optical/X-ray mass estimates? Tx-Bgc is scaled by M 200 -Bgc-Tx relation to reduce to a mass ratio Evolution seen in X-ray-selected CNOC sample at z < 0. 6? Mass ~ Bgc (1+z) = -0. 5 +/- 0. 5 Consistent with self-calibrating model for RCS (Majumdar, later today)

SZ detections BIMA/OVRO observations from Kyle Dawson & J. Carlstrom’s group 6 RCS clusters detected Agreement with X-ray results for Mtot and Mgas requires factor of 2 variation in gas fractions, consistent with lowered X -ray luminosities

AGN in Clusters CNOC: excess of X-ray point sources in a few clusters…. Overall, no strong excess Straight line = expected background Histo = 2 -8 ke. V point sources Ellingson et al. 2005

RCS: analysis just beginning RCS 0224 -002, z=0. 78 regular, lensing cluster, possible small cooling core Excess of sources just inside the virial radius (see also Rudman & Ebeling 2005) Significant energy ejection by AGN? (e. g. , talk by Donahue)

Conclusions RCS Clusters at z > 0. 75 are X-ray sources- all detected “Contamination” by “super group” structures at ~zcluster 1 or 2 out of 12, also X-ray sources X-ray luminosities and gas fractions within R 2500 scatter systematically low. Lx-Tx is not unreasonable- ? steeper? (large error bars!). Virialization of all components is required to produce uniform X-ray/optical relations. Tx-richness relation shows that red galaxies reliably indicate mass (not necessarily virialized). Relation shows some evolution, consistent with self-calibrating N(M, z) models. Further comparisons with dynamics, lensing (HST) , IR luminosity (Spitzer) are under way!