Cosmological Observations with the Cosmic Background Imager

Anthony C.S.Readhead Timothy J.Pearson Steven Padin加利福尼亚理工学院98财年：874,429美元99财年：913,130美元00财年：922,319美元使用宇宙背景成像仪进行宇宙学观测。宇宙微波背景辐射(CMBR)是150亿年前宇宙开始时大爆炸遗留下来的辐射。这种辐射是在宇宙大爆炸后30万年发出的，是我们从早期宇宙接收到的最古老的直接信号。人们认为，重要的宇宙学参数--包括密度参数、哈勃常数和宇宙常数--都在CMBR上留下了印记，可以通过足够灵敏的观测来确定。此外，CMBR必须包含宇宙中所有结构起源的线索--从超星系团和星系团到星系本身，从而到恒星和行星。宇宙背景成像仪是一台用来拍摄CMBR图像并测量其在5角分到1度角尺度(从L=3000到L=300)的角度尺度上的统计特性的仪器。理论模型表明，这些观测可以用来以一定的精度测量基本的宇宙学参数。CBI是一种安装在6.5米平台上的13元干涉仪，运行在26 GHz到36 GHz的10个1 GHz频段。CBI将安装在智利海拔5000米的地方。为了在合理的观测时间内达到所需的灵敏度水平，一个高、干燥的场地是必不可少的。该仪器将在智利现场连续运行2至2.5年。

Anthony C.S. Readhead Timothy J. Pearson Steven Padin California Institute of Technology FY 98: $874,429 FY 99: $913,130 FY 00: $922,319 Cosmological Observations with the Cosmic Background Imager. The cosmic microwave background radiation (CMBR) is the relic radiation left over from the Big Bang with which the Universe began 15 billion years ago. Emitted just 300,000 years after the Big Bang, this radiation is the most ancient direct signal that we receive from the early Universe. It is believed that the important cosmological parameters - including the density parameter, the Hubble constant, and the cosmological constant - all left signatures on the CMBR and can be determined from sufficiently sensitive observations. In addition, the CMBR must contain clues to the origin of all structure in the Universe - from superclusters and clusters of galaxies down to galaxies themselves, and hence to stars and planets. The Cosmic Background Imager (CBI) is an instrument designed to make images of the CMBR and to measure its statistical properties on angular scales from 5 arc minutes to one degree (spherical harmonic scales from l = 3000 down to l = 300). Theoretical models suggest that these observations can be used to measure the fundamental cosmological parameters with some precision. The CBI is a 13-element interferometer mounted on a 6.5-meter platform operating in ten 1-GHz frequency bands from 26 GHz to 36 GHz. The CBI will be installed in Chile at an altitude of 5000 meters. A high, dry site is essential in order to reach the required sensitivity levels in a reasonable observing time. The instrument will be operated at the Chile site continuously over a 2 to 2.5 year period.