A Measurement of the Cosmic Microwave Background Angular Power Spectrum with DASI
A Measurement of the Cosmic Microwave Background Angular Power Spectrum with DASI
复制标题
用DASI测量宇宙微波背景角功率谱
DOI：
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发表时间：
2002
期刊：
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通讯作者：
N. Halverson
中科院分区：
文献类型：
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作者：
N. Halverson
宇宙微波背景辐射（CMB）长期以来一直被认为是关于早期宇宙的惊人信息来源。在这篇论文中，我们描述了设计，
实施，度角尺度干涉仪（DASI），一个紧凑的干涉仪设计用于测量角功率谱的CMB的第一年的结果。我们讨论的光学，接收器和功率谱分析的细节，包括使用约束矩阵投影出污染物和测试与扩散前景模板的相关性。
本文给出了在多极范围1 ~ 100- 900内的九个波段的CMB角功率谱的测量结果。测得的涨落具有与CMB一致的温度谱指数β = -0.1 ± 0.2（1σ）。我们没有发现证据的前景以外的点源的数据。我们检测到的第一个峰值在功率谱在l ~ 200，第二个峰值在功率谱在l ~ 550，和一个上升的功率谱在l ~ 800，这是指示第三，符合暴胀理论。
利用DASI测量沿着COBE DMR数据，在哈勃参数h > 0.45和再电离光学厚度0.0 ≤ τ c ≤ 0.4的保守先验条件下，我们约束宇宙的总密度Ω tot = 1.04 ± 0.06，原始密度涨落的谱指数ns = 1.01。（+0.08）_（-0.06），物理重子密度Ω_bh^2 = 0.022^（+0.004）_（-0.003）等（均为68%置信限）。这些约束与暴胀和大爆炸核合成对Ω_bh^2的估计是一致的。在先验h = 0.72 ± 0.08的条件下，我们约束了物质密度Ω m = 0.40 ± 0.15，真空能量密度Ω Λ = 0.60 ± 0.15，从宇宙微波背景辐射数据中可以看出宇宙中存在暗物质和暗能量。
The Cosmic Microwave Background (CMB) has long been recognized as an astounding source of information about the early Universe. In this thesis we describe the design,
implementation, and first-year results of the Degree Angular Scale Interferometer (DASI), a compact interferometer designed to measure the angular power spectrum of the CMB. We discuss details of the optics, receivers, and power spectrum analysis, including the use of constraint matrices to project out contaminants and test for correlations with diffuse foreground templates.
We present a measurement of the CMB angular power spectrum in the multipole range l ≈ 100- 900 in nine bands. The measured fluctuations have a temperature spectral index of β = -0.1 ± 0.2 (1σ) consistent with CMB. We find no evidence of foregrounds other than point sources in the data. We detect a first peak in the power spectrum at l ~ 200, a second peak in the power spectrum at l ~ 550, and a rise in the power spectrum at l ~ 800 which is indicative of a third, consistent with inflationary theories.
Using the DASI measurement along with COBE DMR data, and adopting conservative priors on the Hubble parameter h > 0.45 and an optical depth due to reionization 0.0 ≤ τ_c ≤ 0.4, we constrain the total density of the Universe Ω_(tot) = 1.04 ± 0.06, the spectral index of the primordial density fluctuations n_s = 1.01^(+0.08)_(-0.06), and the physical baryon density Ω_bh^2 = 0.022^(+0.004)_(-0.003) among others (all 68% confidence limits). These constraints are consistent with inflation and estimates of Ω_bh^2 from Big Bang Nucleosynthesis. With prior h = 0.72 ± 0.08, we constrain the matter density Ω_m = 0.40 ± 0.15, and the vacuum energy density Ω_Λ = 0.60 ± 0.15, indicating from CMB data the presence of dark matter and dark energy in the Universe.