Naidoo, Krishna;
(2020)
Capturing the Cosmic Web for Cosmology.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
In this thesis the minimum spanning tree (MST) is developed to infer cosmological parameters from future galaxy redshift surveys. Studies of the distribution of galaxies typically determine constraints on cosmological models by measuring how galaxies are clustered using two-point statistics. However, these technique do not extract all the information present, especially from the non-linear cosmic web. To incorporate this information the MST is used and is shown to improve constraints on the sum of neutrino masses and parameters from the standard model of cosmology (ΛCDM). In Chapter 2 the MST is introduced and developed in a cosmological context. The MST is shown to be sensitive to information additional to that provided by the power spectrum or the bispectrum. In Chapter 3 the Quijote simulations are used to derive Fisher matrix constraints on the MST and power spectrum. The MST is shown to be much more sensitive to the sum of neutrino masses and when combined with the power spectrum the constraints on ΛCDM parameters improve by a factor ~2. In Chapter 4 the MST is constructed on BOSS galaxies and shown to be consistent with ΛCDM mocks. In the latter Chapters, the effect of large scale structure evolution on light from the cosmic microwave background, known as the integrated Sachs-Wolfe (ISW), are considered. In Chapter 5 voids in ΛCDM are shown to be correlated with the Cold Spot on the CMB. Therefore the discovery of such voids is not evidence of new physics. In Chapter 6, ISW maps for the MICE and Flagship simulations are constructed. These maps will enable studies of the ISW from a larger parameter space. In Chapter 7 the work presented in this thesis is summarised and future work is discussed.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | Capturing the Cosmic Web for Cosmology |
| Event: | UCL |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Copyright © The Author 2020. Original content in this thesis is licensed under the terms of the Creative Commons Attribution 4.0 International (CC BY 4.0) Licence (https://creativecommons.org/licenses/by/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10106440 |
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