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Topics in microwave astronomy and cosmology

Guan, Yilun (2021) Topics in microwave astronomy and cosmology. Doctoral Dissertation, University of Pittsburgh. (Unpublished)

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Over the past decades, precision measurements of the Cosmic Microwave Background (CMB) have led to remarkable progress in our understanding of the universe in what is known as the standard model of cosmology. In this thesis, we demonstrate the potential of high precision CMB dataset in improving our knowledge in both cosmology and astronomy.

In the first part of the thesis, we show that the upcoming CMB experiments may allow us to detect signals from the primordial magnetic field (PMF) and show that a signal from PMF may pose as a source of confusion to the signal from the primordial gravitational waves from inflation. We further show how one can effectively break the degeneracy with the help of precision measurements of the small-scale CMB anisotropies.

In the second part of the thesis, we explore the use of precision measurements of the small-scale CMB anisotropies in constraining physics beyond the standard model. With data obtained from the Atacama Cosmology Telescope (ACT), we search for a signal of parity violating physics in the early universe known as cosmic birefringence. Our non-detection allows us to place a tightest constraint on such effect at the time which improves the previous limit by a factor of 3.

In the next part of the thesis, we demonstrate that the high angular resolution CMB dataset can also be used for galactic science. By combining the CMB datasets from ACT and Planck, we make and present a map of the Galactic center region that improves the previous maps in the microwave frequencies in terms of a wider field of view, higher angular resolution, and sensitivity in both temperature and polarization measurements.

In the last part of the thesis, we discuss the prospects of the upcoming data release (DR6) from ACT which is expected to improve our constraints on cosmological parameters by a factor of 2. I provide a description of an important preprocessing step known as the data cuts pipeline, which identifies data with sporadic pathologies and removes them from the CMB mapmaking, and show the preliminary results from the pipeline for the ACT DR6.


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Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
Guan, Yilunyig20@pitt.eduyig200000-0002-1697-3080
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairKosowsky,
Committee MemberBoyanovsky,
Committee MemberNewman,
Committee MemberBatell,
Committee MemberTrac,
Date: 8 October 2021
Date Type: Publication
Defense Date: 12 July 2021
Approval Date: 8 October 2021
Submission Date: 5 August 2021
Access Restriction: No restriction; Release the ETD for access worldwide immediately.
Number of Pages: 173
Institution: University of Pittsburgh
Schools and Programs: Dietrich School of Arts and Sciences > Physics
Degree: PhD - Doctor of Philosophy
Thesis Type: Doctoral Dissertation
Refereed: Yes
Uncontrolled Keywords: microwave, cosmology, cosmic microwave background, magnetic field, birefringence, galactic center
Date Deposited: 08 Oct 2021 19:39
Last Modified: 08 Oct 2021 19:39


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