Peculiar Velocities and Large Scale Flows as Probes of Gravity, ΛCDM and the Growth of Structure over Cosmic Time
Loading...
Date
2012-09-28T18:32:39Z
Authors
Turnbull, Stephen
Journal Title
Journal ISSN
Volume Title
Publisher
University of Waterloo
Abstract
Peculiar velocities are possibly the most powerful probes of very large-scale mass density fluctuations in the nearby Universe. When coupled with a density field they also can constrain the growth factor of the universe by measuring the proportionality constant between observed velocities and linear theory predicted velocities. In this thesis, I measure a bulk flow of SN within 20,000 km s^1 of 197 +/- 56 km s^1 in direction l = 295 deg +/- 16deg, b = 11deg +/- 14deg , which is consistent with predictions of ΛCDM for large scale mass density fluctuations. Using the IRAS Point Source Catalog Redshift survey (PSCz) galaxy density field and the SNe peculiar velocities I calculated
Ω^55_m σ8 to be 0.40 +/- 0.07 which is in
excellent agreement with the results of WMAP7: Ω^55_m σ8 = 0.39 +/-0.04. By combining my measured value of with results from other studies, I measure the growth factor γ to be = 0.621 +/- 0.08 which is consistent with Λ CDM's prediction of 0.55. I conclude by exploring some of the systematic errors that could have affected my measurements of β. I find that
when β is measured using a reconstruction method the result can be underestimated by
between 7 and 15 %.
Description
Keywords
Gravity, ΛCDM, Peculiar Velocities, Growth of Structure