N(th)-Order Correlation Functions of Galaxies From the Sloan Digital Sky Survey

Ross, Ashley Jacob

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https://hdl.handle.net/2142/85190 Copy

Description

Title

N(th)-Order Correlation Functions of Galaxies From the Sloan Digital Sky Survey

Author(s)

Ross, Ashley Jacob

Issue Date

2009

Doctoral Committee Chair(s)

Brunner, Robert J.

Department of Study

Astronomy

Discipline

Astronomy

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

Physics, Astronomy and Astrophysics

Language

eng

Abstract

I present the correlation function measurements and analysis I have conducted with SDSS data. I have focused my measurements on angular N-point area-averaged correlation functions (o N(theta)) and auto-correlation functions (o2 (theta)) of galaxies. The measured o N(theta) are used to calculate the projected, s N, and real space, SN, hierarchical amplitudes. I have used SDSS DR3 data to show that the measurements are robust against the systematic effects of reddening and seeing, and to determine that large differences exist in the higher-order clustering of early- and late-type galaxies---quantified in terms of bias parameters. Using photometric redshift catalogs from SDSS DR5 data, I have created two volume limited samples of galaxies, allowing me to measure o N(theta) as a function of type, redshift, and luminosity. I have found that the higher-order bias of early-type galaxies does not vary significantly with changes in either redshift or luminosity, as c 2,early is consistent with 0.09 for all measurements. I have shown that the higher-order clustering of late-type galaxies shows dramatic differences for galaxies selected with redshifts above and below z = 0.3. Using LRGs photometrically selected from SDSS DR5, I have measured the 2nd-order bias tern, c 2, using both o2(theta) and s3, and I have combined these measurements to determine that the normalization of the matter power spectrum at 8 h-1 Mpc, sigma8, is 0.79 +/- 0.05 and c2,LRG = 0.09 +/- 0.04---consistent with the DR5 early-type results. I have calculated o2(theta) of galaxies from SDSS DR5 to constrain the HOD of galaxies as a function of type. I found that a new model that separated early- and late-type galaxies into different dark matter halos as much as possible was required to allow good fits to the measurements. Throughout, my findings are interpreted with respect to both the evolution of structure formation and the concept of cosmic downsizing.

Graduation Semester

2009

Type of Resource

text

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http://hdl.handle.net/2142/85190

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