Skip navigation
Please use this identifier to cite or link to this item:
Title: Cosmology from the bispectrum
Authors: Coulton, William
Advisors: Spergel, David N
Contributors: Physics Department
Keywords: Bispectrum
Cosmic microwave background
Subjects: Astrophysics
Issue Date: 2018
Publisher: Princeton, NJ : Princeton University
Abstract: With a suite of current and up-coming experiments set to provide us the with exquisite measurements of the sky in a wide range of frequencies, we are posed with the problem of how to maximally utilize these data sets. Historically two-point function measurements have been the tool of choice, and they have been highly effective. However, two-point functions are unable to extract all the available information, particularly on the small, non-linear scales. With the goal of providing complimentary measurements to the power spectrum, we use the bispectrum to explore a range of physical processes. In the first half of this thesis, we discuss two applications of the bispectrum to probe large scale structure. Firstly, we measure the bispectrum from secondary anisotropies of the cosmic microwave background using data from the Atacama Cosmology telescope and the Planck Satellite. Secondly, we use a suite of simulations to explore the bispectrum of weak lensing shear maps. Using these simulations, we explore how bispectrum measurements can be used to enhance our ability to measure cosmological parameters, including the sum of the masses of the neutrinos. We find that, for an experiment like the Large Synoptic Sky Survey, including information from the bispectrum will enhance parameter constraints by 30%. In the second half of this thesis, we discuss two aspects regarding primordial gravitational waves. First, we discuss how measurements of the bispectrum can be used to probe primordial non-Gaussianity between tensor and scalar fields and present our preliminary constraints on interactions between these fields. Secondly, we discuss how bispectrum measurements of galactic foregrounds, including polarised dust and synchrotron emission, have the potential to help discriminate between the desired signal from primordial gravity waves and galactic contaminants.
Alternate format: The Mudd Manuscript Library retains one bound copy of each dissertation. Search for these copies in the library's main catalog:
Type of Material: Academic dissertations (Ph.D.)
Language: en
Appears in Collections:Physics

Files in This Item:
File Description SizeFormat 
Coulton_princeton_0181D_12685.pdf3.42 MBAdobe PDFView/Download

Items in Dataspace are protected by copyright, with all rights reserved, unless otherwise indicated.