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A measurement of anisotropy in the microwave background on 7'-22' scales


Leitch, Erik M. (1998) A measurement of anisotropy in the microwave background on 7'-22' scales. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/DRVA-T966.


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.

Item Type:Thesis (Dissertation (Ph.D.))
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:
  • Unknown, Unknown
Defense Date:4 March 1998
Non-Caltech Author Email:eml (AT)
Record Number:CaltechETD:etd-08162006-081019
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:3142
Deposited By: Imported from ETD-db
Deposited On:25 Aug 2006
Last Modified:05 Nov 2021 22:40

Thesis Files

PDF (Leitch_em_1998.pdf) - Final Version
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