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H₀ from Cosmic Background Imager Observations of the Sunyaev-Zel’dovich Effect in Nearby Clusters.


Udomprasert, Patricia Simcoe (2004) H₀ from Cosmic Background Imager Observations of the Sunyaev-Zel’dovich Effect in Nearby Clusters. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/VR2Z-MP09.


We present H₀ results from Cosmic Background Imager (CBI) observations of the Sunyaev-Zeldovich Effect (SZE) in 7 galaxy clusters, A85, A399, A401, A478, A754, A1651, and A2597. These observations are part of a program to study a complete, volume-limited sample of low-redshift (z < 0.1), X-ray selected clusters. Our focus on nearby objects allows us to study a well-defined, orientation unbiased sample, minimizing systematic errors due to cluster asphericity. We use density models derived from ROSAT imaging data and temperature measurements from ASCA and BeppoSAX spectral observations. We quantify in detail sources of error in our derivation of H₀, including calibration of the CBI data, density and temperature models from the X-ray data, Cosmic Microwave Background (CMB) primary anisotropy fluctuations, and residuals from radio point source subtraction. From these 7 clusters we obtain a result of Ho = 67+30-18(ran)+15-6(sys) km/s-1 Mpc-1 for an unweighted sample average. The respective quoted errors are random and systematic uncertainties at 68% confidence. The dominant source of error is confusion from intrinsic anisotropy fluctuations. We present results from simulations of an eigenmode weighting analysis that reduce the uncertainties due to CMB in h-1/2 by ~30%.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:cosmology; galaxy clusters
Degree Grantor:California Institute of Technology
Division:Physics, Mathematics and Astronomy
Major Option:Astronomy
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Readhead, Anthony C. S.
Group:Owens Valley Radio Observatory (OVRO), Astronomy Department
Thesis Committee:
  • Lange, Andrew E. (chair)
  • Blain, Andrew W.
  • Djorgovski, George
  • Phinney, E. Sterl
  • Readhead, Anthony C. S.
Defense Date:12 August 2003
Non-Caltech Author Email:pudomprasert (AT)
Record Number:CaltechETD:etd-05132004-184937
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:1771
Deposited By: Imported from ETD-db
Deposited On:28 May 2004
Last Modified:05 Nov 2021 22:38

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