자료유형  

 학위논문

Control Number  

0017164177

International Standard Book Number  

9798384426059

Dewey Decimal Classification Number  

523

Main Entry-Personal Name  

Podczerwinski, John.

Publication, Distribution, etc. (Imprint  

[S.l.] : The University of Wisconsin - Madison., 2024

Publication, Distribution, etc. (Imprint  

Ann Arbor : ProQuest Dissertations & Theses, 2024

Physical Description  

230 p.

General Note  

Source: Dissertations Abstracts International, Volume: 86-03, Section: B.

General Note  

Advisor: Timbie, Peter.

Dissertation Note  

Thesis (Ph.D.)--The University of Wisconsin - Madison, 2024.

Summary, Etc.  

요약This thesis is focused on HI intensity mapping, a proposed method for making three dimensional surveys of the universe. I begin by reviewing basic cosmological theory and common observational techniques such as galaxy surveys and observations of the cosmic microwave background (CMB). I then provide motivation for the use of HI intensity mapping along with a description of how such measurements are performed. I describe my research work, which was focused on developing instrumentation and analysis techniques for HI intensity mapping in the post reionization era of the universe (\uD835\uDC67 6). A key goal of such observations is to monitor the baryon acoustic oscillations over a wide range of redshifts, providing information about the evolution of dark energy. My work focused mainly on the design of an ultra-wideband antenna and the development of foreground cleaning techniques. For the antenna project, I created an ultra-wideband design that was optimized with intensity mapping systematic effects in mind. This involved the use of a Vivaldi feed with optimized profile and a deep dish with and an elliptical collar. I also investigated the use of absorbing materials on the feed antenna, which helped mitigate systematic effects but resulted in significantly lower sensitivity. The final antenna design achieved satisfactory levels of spectral smoothness, impedance matching and sensitivity to the 21 cm hydrogen line. In simulations, I found that my design efforts helped reduce coupling between neighboring antenna elements, though not to the level desired. For the foreground cleaning projects, I investigated the use of Karhunen-Loeve transforms in both map-space and visibility space. My project was the first to incorporate a KL transform in map space. This work, however, did not seem to provide a substantial improvement over other available methods. I then conclude by discussing ideas on the future of HI intensity mapping.

Subject Added Entry-Topical Term  

Astrophysics.

Subject Added Entry-Topical Term  

Physics.

Subject Added Entry-Topical Term  

Astronomy.

Subject Added Entry-Topical Term  

Theoretical physics.

Index Term-Uncontrolled  

HI intensity mapping

Index Term-Uncontrolled  

Cosmic microwave background

Index Term-Uncontrolled  

Galaxy surveys

Index Term-Uncontrolled  

Spectral smoothness

Index Term-Uncontrolled  

Ultra-wideband

Added Entry-Corporate Name  

The University of Wisconsin - Madison Physics

Host Item Entry  

Dissertations Abstracts International. 86-03B.

Electronic Location and Access  

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Control Number  

joongbu:658613