A Multi-Frequency Bolometer Array for Sunyaev-Zel'dovich Astronomy at the Caltech Submillimeter Observatory

LANGE, Andrew E.宇宙微波背景（CMB）辐射为可观测宇宙提供了极其均匀的背光。通过光子-电子（康普顿）散射，在星系团中被引力束缚的热电离等离子体使CMB光子散射，一种被称为Sunyaev-Zel'dovich （SZ）效应的扭曲改变了通过星系团观察CMB的光谱。簇内介质中电子的热和体速度产生明显的光谱畸变，可以通过100至300 GHz范围内的多频率观测来区分。这两个组成部分的分离允许直接确定星系团相对于准惯性CMB静止框架的特殊速度。SZ效应的表面亮度随红移的不变性使得该技术可以扩展到仅受丰富星团存在限制的红移。此外，对星团内部介质的热成分的测量，结合对星团x射线表面亮度的测量，得出了一个非常基本的哈勃常数Ho的值。PI将构建一个新的多频阵列（SuZIE II），该阵列采用频率相关和增加像素数量，以极大地提高观测对SZ效应和微波背景各向异性的灵敏度。SuZIE II将测量许多高红移星团的特殊速度场，高精度测量CMB的弧分尺度各向异性，并根据大量精心挑选的星团样本确定Ho值。＊＊＊

ABSTRACT 9503226 LANGE, Andrew E. The Cosmic Microwave Background (CMB) radiation provides an extremely uniform back light to the observable universe. Through photon-electron (Compton) scattering of the CMB photons with the hot, ionized plasma that is gravitationally bound in clusters of galaxies a distortion known as the Sunyaev-Zel'dovich (SZ) effect alters the spectrum of the CMB when viewed through a cluster. The thermal and bulk velocities of the electrons in the intra-cluster medium produce distinct spectral distortions that can be distinguished from one another by multifrequency observations in the 100 to 300 GHz range. Separation of these two components allows the direct determination of the peculiar velocity of the cluster relative to the quasi-inertial CMB rest frame. The invariance of the surface brightness of the SZ effect with red shift allows this technique to be extended to red shifts limited only by the existence of rich clusters. Also, measurements of the thermal component of the intra-cluster medium combined with measurements of the X-ray surface brightness of the cluster yields a value of the very fundamental Hubble constant, Ho. The PI will construct a new, multi-frequency array (SuZIE II) which employs frequency correlation and an increased number of pixels to greatly increase the sensitivity of observations to the SZ effect and to CMB anisotropy on arcminute scales. SuZIE II will measure the peculiar velocity field of many high red shift clusters, measure the arcminute scale anisotropy of the CMB with high precision, and determine a value for Ho based on a large and carefully selected sample of clusters. ***