Polarization Observations of the Microwave Background Radiation with the Cosmic Background Imager

由于汤姆森散射，宇宙微波背景辐射(CMBR)预计将在10%的水平上偏振，但到目前为止还没有检测到这种偏振。过去两年，宇宙背景干涉仪(CBI)一直在测量CMBR的总强度，经过接收器和观测策略的微小修改，CBI应该能够在一年内探测到偏振。如果目前流行的宇宙学模型的预测是正确的，它还应该测量极化涨落的角功率谱。对微波背景辐射的偏振观测将提供一些重要的宇宙学模型测试。例如，许多具有非标准原始功率谱的宇宙学模型是简并的，标准模型具有不同的关键宇宙学参数值。通过测量极化功率谱和极化与总强度之间的相互关系，有可能进一步检验模型的预测，并打破这些简并。偏振观测还应有助于减少关键宇宙学参数的不确定性，如重子密度、物质密度和宇宙常数，并对再电离时代施加严格限制。这项奖励将允许利用CBI对宇宙微波背景辐射进行高灵敏度(1MK)的偏振观测，范围为L=3001700.*

AST-0206416Readhead, AnthonyThe cosmic microwave background radiation (CMBR) is expected to be polarized at a level of about 10%, owing to Thomson scattering, but as yet this polarization has not been detected. The Cosmic Background Interferometer (CBI) has been measuring the total intensity of the CMBR for the past two years, and with minor modifications to the receivers and the observing strategy, the CBI should be able to detect the polarization within a year. It should also measure the angular power spectrum of polarized fluctuations, if the predictions of currently favored cosmological models arecorrect. Polarization observations of the microwave background radiation will provide a number of important tests of cosmological models. For example many cosmological models with non-standard primordial power spectra are degenerate with standard models having different values of key cosmological parameters. It is possible to further test the predictions of the models and to break these degeneracies by measuring the polarization power spectrum and the cross-correlation between polarization and total intensity. Polarization observations should also help to reduce the uncertainties in key cosmological parameters, such as the baryon density, the matter density and the cosmological constant, and to place stringent limits on the epoch of reionization. This award will allow use of the CBI to make high sensitivity (1 MK) polarization observations of the cosmic microwave background radiation over the angular multipole range l = 300-1700.***