Exploring the parameters of peculiar velocity fields

Islam, Salma (2019) Exploring the parameters of peculiar velocity fields. PhD thesis, University of Glasgow.

Abstract

The main focus of this work is to make use of a novel tool in the cosmologist's toolbox when it comes to constraining the parameters of the peculiar velocity fields of the nearby Universe called ROBUST, whose unique properties and lack of reliance on secondary distance indicators sets it apart from other available constraining techniques, rendering it potentially very useful for future upcoming surveys such as the LSST and the SKA.

While ROBUST proves itself more than adequate in constraining parameters in a mock controlled environment with the IRAS PSCz survey, it begins to struggle when applied to the real-world 2MRS survey, primarily due to an inherent fault in the survey that causes it to not function properly with the program. These problems persist even when we begin to make use of one of the ancillary tools developed in conjunction with ROBUST, namely relative entropy, despite it once again continuing to function adequately across
multiple mock realisations.

It is the conclusion of this work that while ROBUST is not successful in recovering values for the cosmological parameters we seek to constrain, this does not necessarily negate its viability for use with upcoming surveys, as it has proven itself successful in determining exclusion intervals on the value of the linear redshift distortion parameter β for real world surveys that are in very good agreement with the generally small values computed by contemporary velocity-velocity constraining techniques such as VELMOD and χ2 minimisation, while also confidently ruling out the results of older density-density constraining techniques such as POTENT that favour values closer to unity.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Keywords: Cosmology, galaxies, data analysis, dark matter, redshift surveys, peculiar velocities, luminosity functions, ROBUST method, χ2 minimisation, linear redshift distortion parameter, relative entropy.
• Subjects: Q Science > QA Mathematics; Q Science > QB Astronomy; Q Science > QC Physics
• Colleges/Schools: College of Science and Engineering > School of Physics and Astronomy
• Supervisor's Name: Hendry, Professor Martin
• Date of Award: 2019
• Depositing User: Unnamed user with email [e-mail]
• Unique ID: glathesis:2019-41045
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 07 Mar 2019 13:54
• Last Modified: 27 Jul 2022 10:36
• Thesis DOI: 10.5525/gla.thesis.41045
• URI: https://theses.gla.ac.uk/id/eprint/41045