Post on 20-Dec-2015
transcript
CfA Oct 8 2003
Determining the Cosmic Distance Scale with Galaxy
Clusters
Erik Reese
University of California, Berkeley
CfA Oct 8 2003
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 DA relation, where H0 is the normalization
CfA Oct 8 2003
H0 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 8 2003
SystematicsSZE calibration [H0~(∆T0)-2] ± 8%
X-ray calibration ±10%
NH ± 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 8 2003
Challenges
• Systematics• Modeling• Sample selection
– Sample sizes – Unbiassed selection criteria– Wonky clusters
• Convince X-ray TACs• High redshift→cosmology
CfA Oct 8 2003
SZE Surveys
• Large samples of clusters• High redshift clusters• Clean selection function
Holder et al. 2000