Topics in large-scale structure

Abstract

This thesis presents my personal survey of topics and methods in large-scale structure, covering a range of cosmological probes and analytical, numerical, and observational techniques. Chapters 2--4 present analytic calculations of systematic effects relevant for the interpretation of data from upcoming large-scale structure surveys: In chapter 2 we derive the relation between measured galaxy ellipticities and the cosmic shear power spectrum up to fourth order in the matter density field, accounting for multiple deflections along the light path, reduced shear, and magnification bias. In chapter 3 we develop a new third-order cosmic shear statistics, which separates shear three point correlation functions exactly into E- and B-mode correlations on a finite interval. Chapter 4 considers the effect of tidal galaxy alignments on the projected galaxy bispectrum, which are found to bias the inferred galaxy bias parameters. Chapter 5 focusses on the halo-occupation distribution formalism, which constrains the relation between galaxy luminosities and the masses of their host halos through clustering measurements. We extend this method to model the cross-correlation functions between a galaxy sample of interest and multiple tracer populations simultaneously. This technique improves the accuracy of clustering analyses for sparse galaxy populations, and we apply it to constrain the environment of $(NUV-r)$ selected green valley galaxy samples. These galaxy samples are constructed by matching the Sloan Digital Sky Survey with the latest Galaxy Evolution Explorer source catalog which provides NUV photometry. We present cross-correlation function measurements and determine the halo occupation distribution of these transitional galaxies using the multiple tracer technique. In chapter 6 we examine sources of scatter in scaling relations between galaxy cluster mass and thermal Sunyaev-Zeldovich (SZ) effect using cluster samples extracted from cosmological hydrodynamical simulations. This sample enables us to study for the first time the detailed evolution of merging clusters around the scaling relation for a cosmologically representative distribution of merger parameters. We find major mergers to cause an asymmetric scatter such that the inferred mass of merging systems is biased low. As the fraction of dynamically disturbed clusters increases with redshift, this analysis indicates that mergers cause a redshift-dependent bias in cluster mass scaling relations.