CfA Oct Determining the Cosmic Distance Scale with Galaxy Clusters Erik Reese University of California, Berkeley

CfA Oct The Sunyaev-Zel’dovich Effect

CfA Oct BIMA & OVRO

CfA Oct

Distance Calculation With geometry of the cluster

CfA Oct Hubble Constant With z and geometry of the universe Independent of the extra-galactic distance ladder! For a sample of clusters, fit to the theoretical D A relation, where H 0 is the normalization

CfA Oct Angular Diameter Distances: Present

CfA Oct H 0 Current Results Ryle → 5 clusters (Jones et al. 2003) OVRO 5m → 7 clusters (Mason et al. 2000) OVRO/BIMA → 18 clusters (Reese et al. 2002)

CfA Oct H 0 Current Results Combined → 41 distances Reminder: All ROSAT data

CfA Oct Systematics SZE calibration [H 0 ~(∆T 0 ) -2 ]± 8% X-ray calibration±10% NHNH ± 5% Asphericity ● ± 5% Isothermality±10% Clumping−20% Undetected radio sources±12% Kinetic SZE ● ± 2% Primary CMB ● ± 1% Radio Halos± 4% Primary Beam± 3% Total+22% −30%

CfA Oct Chandra

CfA Oct Angular Diameter Distances: Chandra

CfA Oct D A Future

CfA Oct Supernovae Type Ia

CfA Oct Challenges Systematics Modeling Sample selection –Sample sizes –Unbiassed selection criteria –Wonky clusters Convince X-ray TACs High redshift→cosmology

CfA Oct SZE Surveys Large samples of clusters High redshift clusters Clean selection function Holder et al. 2000

CfA Oct Simulations Courtesy of Martin White

CfA Oct Summary H 0 independent of extragalactic distance ladder Systematics are approachable SZE Surveys –Large numbers of clusters –High redshift –Sample selection Symbiotic with cluster number counts