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Degree

Doctor of Philosophy, Ohio State University, Physics, 2003.

Abstract

The radiation in the Cosmic Microwave Background (CMB) last scattered off of matter during the epoch of recombination, when nuclei captured electrons for the first time, and its predicted anisotropy power spectra are sensitive to the details of recombination. In light of recent high quality observations of the CMB, it is worthwhile to re-examine the constraints that can be placed on recombination. We use a very general extension to the standard model of recombination characterized by two parameters, a and b, which multiply the overall rates of recombination and ionization and the binding energies of hydrogen respectively. We utilize WMAP temperature and TE cross-correlation data, along with temperature data at smaller scales from ACBAR and CBI, to place constraints on these parameters. The range of recombination histories which are the best match to the data fall within the range -0.4 ≤ log(a) ≤ 0.4 and 0.9 ≤ b ≤ 1.1, forming a diagonal region from low-a/high-b to high-a/low-b. We find z_rec = 1055 ± 25 and Δz = 84 ± 2 at 68% confidence for the range of recombination models which are best able to reproduce the observed CMB power spectra. Standard recombination is an entirely acceptable fit to the data. We conclude that there is still leeway for non-standard recombination, but the window is narrowing.

Subject Headings

Physics, Astronomy and Astrophysics

Keywords

recombination; cosmic microwave background; cosmology

Advisor

Robert J. Scherrer

Pages

110p.

Document number: osu1062095232
Permalink: http://rave.ohiolink.edu/etdc/view?acc_num=osu1062095232

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