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A Search for Cosmic Microwave Background Anisotropies on Arcminute Scales


Sayers, Jack (2008) A Search for Cosmic Microwave Background Anisotropies on Arcminute Scales. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/2Q9Q-JA33.


This thesis describes the results of two sets of observations made in 2003 and 2004 using Bolocam from the Caltech Submillimeter Observatory (CSO), along with a description of the design and performance of the instrument. Bolocam is a large format camera consisting of 144 bolometers with an eight arcminute field of view at the CSO, and can be operated non-simultaneously at 1.1, 1.4, or 2.1 mm. All of the data described in this thesis was collected at 2.1 mm, where the individual beams are approximately one arcminute in size. The observations were made over a total of seventy-nine nights, and consisted of surveys of two science fields, Lynx and the Subaru/XMM Deep Field (SDS1), covering a total area of approximately 1 square degree. The noise properties of the maps are extremely uniform, with RMS variations in coverage of approximately 1.5% for twenty arcsecond map pixels. The point source sensitivity of the maps is approximately 100 μKCMB per beam. Fluctuations in emission from the atmosphere limited the sensitivity of our measurements, and several algorithms designed to remove these fluctuations are described. These algorithms also removed astronomical flux, and simulations were used to determine the effect of this attenuation on a CMB power spectrum. Assuming a flat CMB band power in C, our data corresponds to an effective angular multipole of ℓeff = 5700, with a FWHM = 2800. At these scales the CMB power spectrum is expected to be dominated by anisotropies induced by the Sunyaev-Zel'dovich effect (SZE), and have a reasonably flat spectrum. Our data is consistent with a band power of C = 0 μK2CMB1, and an upper limit of C < 755 μK2CMB at a confidence level of 90%. From this result we find that σ8 < 1.55 at a confidence level of 90%.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:atmospheric noise; bolometers; CMB; cosmology; galaxy clusters; Sunyaev-Zeldovich
Degree Grantor:California Institute of Technology
Division:Physics, Mathematics and Astronomy
Major Option:Physics
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Golwala, Sunil
Group:Caltech Submillimeter Observatory, Astronomy Department
Thesis Committee:
  • Golwala, Sunil (chair)
  • Lange, Andrew E.
  • Kamionkowski, Marc P.
  • Frautschi, Steven C.
Defense Date:5 December 2007
Non-Caltech Author Email:jack (AT)
Record Number:CaltechETD:etd-12232007-013248
Persistent URL:
Sayers, Jack0000-0002-8213-3784
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:5130
Deposited By: Imported from ETD-db
Deposited On:16 Jan 2008
Last Modified:10 Mar 2020 19:21

Thesis Files

PDF (Sayers_thesis_20071231.pdf) - Final Version
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