Cosmology from Cosmic Microwave Background and large- scale structure

Details Cosmology from Cosmic Microwave Background and large- scale structure Cosmology from Cosmic Microwave Background and large- scale structure

Oct 2003

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2003phdt.........1x&link_type=abstract

Thesis (PhD). UNIVERSITY OF PENNSYLVANIA, Source DAI-B 64/04, p. 1767, Oct 2003, 188 pages.

Mathematics

Logic

4

Scientific paper

This dissertation consists of a series of studies, constituting four published papers, involving the Cosmic Microwave Background and the large scale structure, which help constrain Cosmological parameters and potential systematic errors. First, we present a method for comparing and combining maps with different resolutions and beam shapes, and apply it to the Saskatoon, QMAP and COBE/DMR data sets. Although the Saskatoon and QMAP maps detect signal at the 21σ and 40σ, levels, respectively, their difference is consistent with pure noise, placing strong limits on possible systematic errors. In particular, we obtain quantitative upper limits on relative calibration and pointing errors. Splitting the combined data by frequency shows similar consistency between the Ka- and Q-bands, placing limits on foreground contamination. The visual agreement between the maps is equally striking. Our combined QMAP+Saskatoon map, nicknamed QMASK, is publicly available at www.hep.upenn.edu/˜xuyz/qmask.html together with its 6495 x 6495 noise covariance matrix. This thoroughly tested data set covers a large enough area (648 square degrees—at the time, the largest degree-scale map available) to allow a statistical comparison with LOBE/DMR, showing good agreement. By band-pass-filtering the QMAP and Saskatoon maps, we are also able to spatially compare them scale-by-scale to check for beam- and pointing-related systematic errors. Using the QMASK map, we then measure the cosmic microwave background (CMB) power spectrum on angular scales ℓ ˜ 30 200 (1° 6°), and we test it for non-Gaussianity using morphological statistics known as Minkowski functionals. We conclude that the QMASK map is neither a very typical nor a very exceptional realization of a Gaussian random field. At least about 20% of the 1000 Gaussian Monte Carlo maps differ more than the QMASK map from the mean morphological parameters of the Gaussian fields. Finally, we compute the real-space power spectrum and the redshift-space distortions of galaxies in the 2dF 100k galaxy redshift survey using pseudo-Karhunen-Loève eigenmodes and the stochastic bias formalism. Our results agree well with those published by the 2dFGRS team, and have the added advantage of producing easy-to-interpret uncorrelated minimum-variance measurements of the galaxy- galaxy, galaxy-velocity and velocity-velocity power spectra in 27 k-bands, with narrow and well-behaved window functions in the range 0.01 h /Mpc < k < 0.8 h/Mpc. We find no significant detection of baryonic wiggles. We measure the galaxy-matter correlation coefficient r > 0.4 and the redshift-distortion parameter β = 0.49 ± 0.16 for r = 1.

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