Collaborative Research with the Atacama Cosmology Telescope (ACT): Probing Fundamental Physics Through Observations of Cosmic Structure

最近在观测和理论宇宙学方面令人兴奋的发现使我们得以一窥新的基础物理学。我们对宇宙的内容和命运的概念比五年前更清晰，也有了很大的不同。我们现在相信宇宙在几何上是平坦的，由~5%的重子，~30%的暗物质和~65%的新形式的暗能量组成。通过一个高度连锁的观察程序，复杂的数据分析和理论，参与这个合作项目的研究人员希望扩大我们的知识远远超出当前一代调查的能力。探测器技术的革命，即千元测辐射热阵列，为物理宇宙的新发现打开了大门。该小组将把基于这些实地测试阵列的三色毫米相机与位于智利海拔5000米以上的专门的6米直径望远镜相结合。使用这种仪器进行观测可以绘制出宇宙结构的形成，从高红移（z 1000）的线性区域到结构形成时的低红移（z 5）的非线性区域。10米级望远镜的光谱学和现代X射线卫星的测量将能够确定数百个星系团的红移和质量，这是宇宙演化的最新阶段。通过一系列的观测--宇宙微波背景（CMB）、光学、X射线--研究人员将探测宇宙的图像，其深度超过迄今为止的探测深度。阿塔卡玛宇宙学望远镜（ACT）项目的目标是：1。绘制超过100平方度的CMB温度各向异性图，超出WMAP（运行）和普朗克（2007年发射）卫星的分辨率限制。初级各向异性限制了婴儿宇宙的基本物理学，并为结构形成提供了初始条件;次级各向异性反映了结构的出现。2.通过Sunyaev-Zel'dovich效应发现并研究CMB地图区域内的星系团，并确定其中400多个星系团的光谱红移。这些星团的质量将通过X射线观测和星系速度色散来测量。3.结合联合收割机的高保真CMB地图数据和集群测量，找到状态方程，w = p/p的“精华”或“暗能量”到+0.1。 4.根据CMB图和星系团的测量结果，将中微子的质量限制在+0.1 eV。 5.使用CMB地图构建0.2度分辨率的引力透镜位移地图，这将直接探测z ~ 1至2处1 Mpc长度尺度上的总质量分布。这项技术是独立的，并补充了较低的红移星系调查（其中涉及偏见）。 6.通过CMB中的Ostriker-Vishniac效应，从z ~ 10的第一批恒星的形成中探测宇宙的再电离。该研究小组将与ACT项目一起开展一系列教育、宣传和技术转让活动。一个特别值得注意的项目是为纽约城市大学的少数民族学生提供研究经验。 本科生和研究生以及博士后将通过参与ACT项目的各个方面接受高级培训。宇宙学研究抓住了公众的想象力，预计该项目的结果将引起媒体的广泛关注。 在NSF内部，ACT项目的资助伙伴是天文科学处、物理学处和数学和物理科学理事会多学科活动办公室。 ***

AST-0408698PageExciting recent discoveries in observational and theoretical cosmology have given us a glimpse of new fundamental physics. Our conception of the contents and fate of the Universe is clearer and dramatically different than it was just five years ago. We now believe the Universe is geometrically flat and comprised of ~5% baryons, ~30% dark matter, and ~65% a new form of dark energy. Through a highly interlocking program of observations, sophisticated data analysis, and theory, the researchers involved in this collaborative project expect to expand our knowledge well beyond the capabilities of the current generation of investigations. A revolution in detector technology, namely thousand-element bolometric arrays, has opened the door to new discoveries about the physical Universe. This group will couple a three-color millimeter camera based on these field-tested arrays to a specialized, 6-meter diameter telescope to be located at an altitude above 5000 m in Chile. Observations with this instrument can map out the formation of cosmic structure from the high-redshift (z 1000) linear regime through the low-redshift (z 5) non-linear regime when structures form. Optical spectroscopy with 10-meter class telescopes and measurements with modern X-ray satellites will enable the determination of the redshifts and masses of hundreds of galaxy clusters, the latest stage of cosmic evolution. Through a combination of observations - Cosmic Micowave Background (CMB), optical, X-ray - the researchers will probe the picture of the Universe to greater depths than have yet been plumbed. Goals of the Atacama Cosmology Telescope (ACT) project are to: 1. Map the CMB temperature anisotropy over 100 square deg, beyond the resolution limits of the WMAP (operating) and Planck (launch 2007) satellites. The primary anisotropy constrains the fundamental physics of the infant Universe and provides the initial conditions for structure formation; the secondary anisotropies reflect the emergence of structure. 2. Find and study galaxy clusters in the CMB map region through the Sunyaev-Zel'dovich effect and determine the spectroscopic redshifts of over 400 of them. The masses of these clusters will be measured with X-ray observations and with galaxy velocity dispersions. 3. Combine the high fidelity CMB map data and the cluster measurements to find the equation of state, w = p/p of the "quintessence" or "dark energy" to +0.1. 4. Limit or determine the mass of the neutrino to +0.1 eV from the combined CMB map and cluster measurements. 5. Use the CMB maps to construct gravitational lensing displacement maps at 0.2 degree resolution, which will probe the total mass distribution directly on length scales of 1 Mpc at z ~ 1 to 2. This technique is independent of and complementary to lower redshift galaxy surveys (which involve bias). 6. Detect reionization of the Universe from the formation of the first stars at z ~ 10 through the Ostriker-Vishniac effect in the CMB.This research team will conduct a range of activities in education, outreach, and technology transfer in conjunction with the ACT project. One program of special note gives research experience to minority students at City University of New York. Undergraduate and graduate students as well as postdocs will receive advance training through participation in all aspects of the ACT project. Cosmology research captures the public imagination, and the results of this project are expected to generate considerable media attention. Within NSF, the funding partners for the ACT project are the Division of Astronomical Sciences, the Division of Physics, and the Office of Multidisciplinary Activities in the Directorate for Mathematical and Physical Sciences. ***