DC Field | Value | Language |
---|---|---|
dc.contributor.advisor | Stewart, Ewan D. | - |
dc.contributor.advisor | 유안 스튜어트 | - |
dc.contributor.author | Hong, Sung-Wook E. | - |
dc.contributor.author | 홍성욱 | - |
dc.date.accessioned | 2011-12-14T07:28:56Z | - |
dc.date.available | 2011-12-14T07:28:56Z | - |
dc.date.issued | 2011 | - |
dc.identifier.uri | http://library.kaist.ac.kr/search/detail/view.do?bibCtrlNo=466329&flag=dissertation | - |
dc.identifier.uri | http://hdl.handle.net/10203/47662 | - |
dc.description | 학위논문(박사) - 한국과학기술원 : 물리학과, 2011.2, [ viii, 48p. ] | - |
dc.description.abstract | This thesis includes two independent works on dark energy and the cosmic dark ages. (1) Weinberg {\it et al.} calculated the anthropic likelihood of the cosmological constant $\Lambda$ using a model assuming that the number of observers is proportional to the total mass of gravitationally collapsed objects, with mass greater than a certain threshold at $t \to \infty$. We modify Weinberg`s model in a way that the number of observers is proportional to the number of collapsed objects, with mass and time equal to certain preferred mass and time scales. Unlike Weinberg`s model, the anthropic likelihood of the primordial density perturbation amplitude $Q$ from our model explains $Q_0$ well without any additional constraint. Furthermore, observers will be affected by the history of the collapsed object, and we introduce a method to calculate the anthropic likelihoods of $\Lambda$ and $Q$ from the mass history using the extended Press-Schechter formalism. In contrast to models using only a single mass constraint, the results from the models using the mass history are robust even if we allow both $\Lambda$ and $Q$ to vary. (2) We propose a topological analysis method of 21-cm signal using the 2D genus curve, a function defined as the difference of the number of hot regions and the number of cold regions, compared to a given temperature. We show that the 2D genus curve of the differential brightness temperature, $g_\mathrm{2D} (\delta T_\mathrm{b})$, by comparing to $g_\mathrm{2D}$ of the density fluctuation, $g_\mathrm{2D} (\delta T_\mathrm{b,n})$, clearly shows the evolution of the reionization process. We also show that the 2D genus topology method can effectively distinguish different reionization scenarios, especially with different source photon efficiency for a low-mass source $10^8 \lesssim M / M_\odot \lesssim 10^9$ and with different greatest ionized bubble size. In terms of the design of future detection, we show that observational beams insensitive to la... | eng |
dc.language | eng | - |
dc.publisher | 한국과학기술원 | - |
dc.subject | Cosmic Reionization | - |
dc.subject | Anthropic Principle | - |
dc.subject | Cosmological Constant | - |
dc.subject | Cosmology | - |
dc.subject | 2D Genus Topology | - |
dc.subject | 2차원 종수 함수 분석법 | - |
dc.subject | 우주 재이온화 | - |
dc.subject | 인간 중심적 원리 | - |
dc.subject | 우주 상수 | - |
dc.subject | 우주론 | - |
dc.title | From dark to dark: Anthropic selection of cosmological parameters and an analysis method for signals from cosmic reionization | - |
dc.title.alternative | 암흑에서 암흑으로: 인간 중심적 선택 효과와 우주 재이온화 시기의 신호 분석 | - |
dc.type | Thesis(Ph.D) | - |
dc.identifier.CNRN | 466329/325007 | - |
dc.description.department | 한국과학기술원 : 물리학과, | - |
dc.identifier.uid | 020047999 | - |
dc.contributor.localauthor | Hong, Sung-Wook E. | - |
dc.contributor.localauthor | 홍성욱 | - |
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.