DETERMINATION OF THE HUBBLE CONSTANT FROM X-RAY AND SUNYAEV-ZELDOVICH EFFECT OBSERVATIONS OF HIGH-REDSHIFT GALAXY CLUSTERS MAX BONAMENTE – UNIVERSITY OF ALABAMA IN HUNTSVILLE MARSHALL JOY – NASA MSFC SAM LAROQUE, JOHN CARLSTROM – UNIVERSITY OF CHICAGO (Credit: Joy et al. 2001)

Sunyaev-Zel'dovich Effect Observations OVRO BIMA (Credit: Carlstrom et al., (2002) Observable: Temperature decrement

(Carlstrom et al. (2002) Clusters of similar mass have a redshift- independent SZE effect

X-ray Observations Have SZE/X-ray available for 38 clusters, z= (Bonamente et al. 2006, ApJ 647, 25; LaRoque et al ApJ 652, 917) Observables: Surface brightness CHANDRA (with BIMA decrement contours overlaid) (Credit: Bonamente et al. 2006) and temperature distribution

How to measure distances with X-ray and SZE observations Without assumptions on cosmological parameters, one can derive simultaneously distance D A and density n e of the emitting/scattering gas Main advantages of this method: Independent of Cepheid calibration (no standard candles needed) Reaches high redshift (z~1) Joint use of X-ray and SZE observations

CLUSTERZ Z CL ABELL ABELL RX J ABELL MS ABELL ABELL MS MACS J MACS J ABELL ABELL ABELL MACS J ABELL ABELL ABELL ABELL ABELL ABELL ABELL ABELL RX J ZW ABELL MACS J ABELL MS MS MS MACS J MACS J RX J ABELL MAC J CL J MACS J MACS J SZE/X-ray sample

Models of the gas distribution Use three models for the intra-cluster medium: (1) Simple isothermal beta model (2) Isothermal beta model with 100 kpc cut (3) Non-isothermal, hydrostatic equilibrium model with arbitrary temperature profile and double-beta model density distribution: Use a MCMC method, in which model parameters are used to predict the observables: surface brightness; temperature profile; SZE decrement; then compare with the observations in order to do parameter estimation.

(Credit: Bonamente et al. 2006) Examples of non isothermal modeling of intra-cluster medium SURFACE BRIGHTNESS TEMPERATURE PROFILE

Hubble diagram (D A vs. z) for hydrostatic equilibrium model (Credit: Bonamente et al. 2006)

“ [The SCDM fits]... have the same quality as that for the currently favored LCDM cosmology, indicating that cluster distances alone can not yet effectively constrain the energy density parameters...” (Bonamente et al. 2006) Comparison of Hubble diagrams for all 3 models (Credit: Bonamente et al. 2006)

Other methods to measure the Hubble constant Cepheid calibration of secondary distance indicators: Freedman et al. (2001) (Credit: Freedman et al. (2001)

Cepheid calibration of supernovae type Ia (requires absolute calibration of peak luminosity): Riess et al. (2004, 2005) (Credit: Riess et al. (2005)

Indirect measurement from WMAP: Spergel et al (2007) (Credit: Spergel et al. (2007) “ The CMB data do not directly measure H 0 ; however, by measuring  m H 0 2 [...] the CMB produces a determination of H 0 if we assume a simple flat LCDM model” (Spergel et al. 2007)

After about 80 years, it all seems to hang together for the Hubble constant... (Credit: Freedman et al. (2001) Summary:

(Credit: Freedman et al. (2001) 2006 CEPHEIDS SZE Cepheid-based and SZE-based agree on Hubble constant, current uncertainty is %