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Type of Document	Dissertation
Author	Leitch, Erik M.
Author's Email Address	eml AT astro.caltech.edu
URN	etd-08162006-081019
Persistent URL	http://resolver.caltech.edu/CaltechETD:etd-08162006-081019
Title	A measurement of anisotropy in the microwave background on 7'-22' scales
Degree	PhD
Option	Astronomy
Advisory Committee	Advisor Name Title Timothy J. Pearson Committee Chair Ben R. Oppenheimer Committee Member Steven T. Myers Committee Member
Keywords	none
Date of Defense	1998-03-04
Availability	unrestricted
Abstract NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document. A measurement of the anisotropy of the cosmic microwave background radiation (CMBR) at 7'-22' scales is described. Observations of 36 blank fields near the North Celestial Pole (NCP) were made at 31.7 and 14.5 GHz, using two High Electron Mobility Transistor (HEMT) amplified radiometers. These observations were conducted at the Owens Valley Radio Observatory from 1993-1996. We detect a significant signal, with temperature spectral index consistent with emission from a combination of a steep-spectrum foreground ([beta] < -2) and CMBR ([...]). Multi-epoch VLA observations at 8 and 15 GHz allow removal of any discrete source contamination at 14.5 and 31.7 GHz. On the basis of low-frequency maps of the NCP, we can rule out emission with [beta] < -2.2. Although the foreground signal dominates at 14.5 GHz, the extracted CMBR component contributes nearly 90% of the variance at 31.7 GHz, yielding an rms fluctuation amplitude of [...], including calibration uncertainty and sample variance. In terms of the angular power spectrum [...] averaged over a range of multipoles [...], we have [...]. The extracted foreground component is found to correlate significantly with IRAS 100 [mu] m dust emission. Lack of H [alpha] emission near the NCP suggests that the foreground is either high-temperature thermal bremsstrahlung [...], flat spectrum synchrotron, or an exotic component of dust emission.
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