Peculiar Velocities and Large Scale Flows as Probes of Gravity, ΛCDM and the Growth of Structure over Cosmic Time

[摘要] Peculiar velocities are possibly the most powerful probes of very large-scale mass density fluctuations in the nearby Universe. When coupled with a densityfield 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 ofΛCDM 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_mσ8 to be 0.40 +/-0.07 which is inexcellent agreement with the results of WMAP7:Ω^55_mσ8 = 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 ofβ. I find thatwhenβ is measured using a reconstruction method the result can be underestimated bybetween 7 and 15 %.

[发布机构] University of Waterloo

[效力级别] ΛCDM

[关键词] Gravity;ΛCDM;Peculiar Velocities;Growth of Structure;Physics