RUI: The Universe at Redshifts 1-1000

RUI：红移 1-1000 的宇宙

• 批准号: 9616971
• 负责人: R. Partridge
• 金额: $ 20.4万
• 依托单位: Haverford College
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-05-01 至 2002-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9616971&HistoricalAwards=false
• 关键词: RUI; Universe; Redshifts; 1000

ABSTRACT Partridge The galaxies and clusters now visible in the Universe grew from small perturbations in density present at very early times, corresponding to redshifts 1000. Many details of this evolutionary process are poorly understood. In particular, we have only rudimentary (but rapidly improving) understanding of the formation of cosmic structure in the first 5 billion years after the recombination of the primeval plasma, that is in the large range of redshifts 1-1000. Refined radio-wavelength searches for various classes of fluctuations in the cosmic microwave background radiation (CBR) will tell us more about the early phases of structure formation, at the high end of this crucial redshift interval. Optical, IR and radio observations of galaxies or galaxy fragments at z = 1-3 are already providing important clues to the final stages of galaxy formation (e.g., the onset of star formation). Searches for CBR fluctuations and radio wavelength observations of high redshift galaxies will be carried out. The goal of the research is to help bridge the gap in our understanding of cosmic evolution during the epoch corresponding to redshifts (z) = 1-1000. A study of the Hubble Deep Field at radio wavelengths will be carried out. The Hubble Deep Field (HDF) is a small but typical region of the sky selected by astronomers for intensive study at all wavelengths, beginning with a very deep Space Telescope exposure late last year. The aim is to use observations across the electromagnetic spectrum to move our understanding of galaxy evolution forward. Our radio observations will be carried out at the Very Large Array at 8.4 and 1.4 GHz and with angular resolution from 10" down to 0.4" (close to the Space Telescope resolution). Among the scientific goals of our observations are: --measuring radio spectra and morphologies to determine the nature of the radio emission (synchrotron from supernova activity? active galactic nuclei?) --refining counts of radio source s at low flux densities --examining the correlation of radio and optical luminosities --improving limits on fluctuations in the CBR on angular scales 6"-80" --searching for the microwave signals produced by clusters or protoclusters of galaxies at z 1. Several related projects will parallel these efforts, including further work on foreground sources of noise which interfere with searches for CBR fluctuations, planning for a European space mission to map the CBR, and near infrared observations of both high redshift galaxies already observed at the VLA and of the 2-4 micron cosmic microwave background. A postdoctoral associate will assist in some or all of these projects. The position is intended, however, to provide the postdoc with further experience and training in both teaching and research. In addition to his or her research involvement, the postdoc would design and teach one course per year at Haverford, under the close supervision and mentoring of members of our department. Undergraduate students will be involved in various aspects of the research.

摘要 鹧鸪 现在宇宙中可见的星系和星团是由极早期存在的密度小扰动产生的，对应于红移 1000。这一演化过程的许多细节人们知之甚少。特别是，我们对原始等离子体重组后的前 50 亿年（即红移 1-1000 的大范围内）宇宙结构的形成只有初步的（但正在迅速改善）了解。 对宇宙微波背景辐射（CBR）中各种波动的精确无线电波长搜索将告诉我们更多有关结构形成早期阶段的信息，即这个关键红移区间的高端。对 z = 1-3 处的星系或星系碎片的光学、红外和射电观测已经为星系形成的最后阶段（例如恒星形成的开始）提供了重要线索。 将开展高红移星系的CBR涨落搜索和射电波长观测。 这项研究的目标是帮助弥合我们对红移 (z) = 1-1000 时期宇宙演化的理解差距。 将在无线电波长下对哈勃深场进行研究。 哈勃深场（HDF）是一个小而典型的天空区域，天文学家从去年年底的一次非常深的太空望远镜曝光开始，选择对所有波长进行深入研究。目的是利用整个电磁频谱的观测来推动我们对星系演化的理解。我们的无线电观测将在 8.4 和 1.4 GHz 的甚大阵列上进行，角分辨率从 10 英寸到 0.4 英寸（接近太空望远镜分辨率）。 我们观测的科学目标包括： - 测量射电频谱和形态以确定射电发射的性质（来自超新星活动的同步加速器？活跃星系核？） - 细化低通量密度下射电源的计数 - 检查射电和光学光度的相关性 - 改善 CBR 在 6 英寸-80 英寸角尺度上波动的限制 ——搜索 z 1 处的星系团或原星系团产生的微波信号。几个相关项目将与这些工作并行，包括对干扰 CBR 波动搜索的前景噪声源的进一步研究、计划绘制 CBR 地图的欧洲太空任务、以及对 VLA 已经观测到的高红移星系和 2-4 微米宇宙微波背景的近红外观测。 博士后助理将协助部分或全部这些项目。然而，该职位的目的是为博士后提供进一步的教学和研究经验和培训。除了参与研究之外，博士后每年还将在我们系成员的密切监督和指导下在哈弗福德设计和教授一门课程。 本科生将参与各个方面的研究。