A detection of cosmological 21 cm emission from CHIME in cross-correlation with the eBOSS Lyman-𝜶 forest
department or school: Science, Faculty of
department or school: Physics and Astronomy, Department of
data provider: DSpace
degree campus: UBCV
creator: Pinsonneault-Marotte, Tristan
issued: 2023-10-05T19:25:17Z
issued: 2023
related degree: Doctor of Philosophy - PhD
degree grantor: University of British Columbia
description: The Canadian Hydrogen Intensity Mapping Experiment (CHIME) is a radio telescope that we built to map the large-scale structure of the Universe between redshifts 0.8 and 2.5, when dark energy is expected to begin the transition from a decelerating to an accelerating phase in the expansion of the Universe. CHIME was designed to perform an intensity mapping survey using the 21 cm line of neutral hydrogen, a novel method that has the potential to enable enormous surveys of the distant Universe, but also significant observational challenges to overcome. In this thesis, I describe contributions I made to the CHIME data acquisition system and calibration effort, culminating in a detection of cosmological 21 cm emission in cross-correlation with measurements of the Lyman-𝜶 forest. The large data rate from the CHIME correlator is processed in real time by a high-performance digital pipeline, the development of which I participated in extensively. A few specific processing tasks where I led the design and implementation are highlighted in this work. In order to detect the 21 cm signal amidst the much brighter foreground emission from nearby sources, a very precise instrumental calibration is required. Calibrating the telescope's beam is a particular concern. One of many approaches being pursued for CHIME is the holographic observation of bright celestial sources in concert with a second radio telescope. I describe work I did to derive beam measurements from such observations and their analysis, including a scheme for calibrating the polarised beam response. I report the detection of 21 cm emission at an average redshift z = 2.3 in the cross-correlation of CHIME maps with measurements of the Lyman-𝜶 forest from the eBOSS. Data collected by CHIME over 88 days in the 400-500 MHz frequency band (1.8 < z < 2.5) were formed into maps of the sky and high-pass delay filtered to suppress the foreground power. Line-of-sight spectra to the eBOSS background quasar locations were extracte…
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/86082
note: A Detection of Cosmological 21 cm Emission fromCHIME in Cross-correlation with the eBOSSLyman-α ForestbyTristan Pinsonneault-MarotteMSc Physics, University of British Columbia, 2018BSc Honours Physics, McGill University, 2016a thesis submitted in partial fulfillmentof the requirements for the degree ofDoctor of Philosophyinthe faculty of graduate and postdoctoralstudies(Physics)The University of British Columbia(Vancouver)October 2023© Tristan Pinsonneault-Marotte, 2023The following individuals certify that they have read, and recommend to the Facultyof Graduate and Postdoctoral Studies for acceptance, the thesis entitled:A Detection of Cosmological 21 cm Emission from CHIME inCross-correlation with the eBOSS Lyman-α Forestsubmitted by Tristan Pinsonneault-Marotte in partial fulfillment of the require-ments for the degree of Doctor of Philosophy in Physics.Examining Committee:Gary Hinshaw, Professor, Physics and Astronomy, UBCSupervisorMark Halpern, Professor, Physics and Astronomy, UBCSupervisory Committee MemberDouglas Scott, Professor, Physics and Astronomy, UBCUniversity ExaminerEd Grant, Professor, Chemistry, UBCUniversity ExaminerAdditional Supervisory Committee Members:Scott Oser, Professor, Physics and Astronomy, UBCSupervisory Committee MemberDavid Morrissey, Adjunct Assistant Professor, Physics and Astronomy, University ofVictoria; Research Scientist, TRIUMFSupervisory Committee MemberiiAbstractThe Canadian Hydrogen Intensity Mapping Experiment (CHIME) is a radio telescopethat we built to map the large-scale structure of the Universe between redshifts 0.8and 2.5, when dark energy is expected to begin the transition from a deceleratingto an accelerating phase in the expansion of the Universe. CHIME was designed toperform an intensity mapping survey using the 21 cm line of neutral hydrogen, a novelmethod that has the potential to enable enormous surveys of the distant Universe,but also significant observational challenges to overcome. In this thesis, I descr…
has type: Thesis/Dissertation
date issued: 2023-11
is shown at: 10.14288/1.0436953
language: eng
degree discipline: Physics
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-NonCommercial-NoDerivatives 4.0 International
rights URI: http://creativecommons.org/licenses/by-nc-nd/4.0/
scholar level: Graduate
contributor: Hinshaw, Gary
type: Text
identifier URI: http://hdl.handle.net/2429/86082