Gravitation, Relativity and Cosmology

这个小组通过银河系外天文学和宇宙学的实验和理论工作来研究重力物理学。COBE对2.7K热宇宙背景辐射（CBR）各向异性的探测表明，这种波动足够大，可以从地面和气球上进行研究。从30弧分到大约10>的COBE分辨率，各向异性的特征似乎可能是结构性质和起源理论的一个强有力的判别力。将继续发展绘制CBR的技术和分析角度起伏的起源理论。CBR光谱的长波长部分对星系间介质的演化具有重要的约束作用，但该光谱尚未得到很好的测量。研究将继续采用一种系统的方法来处理主要的实验问题，即将CBR从我们星系的发射物中分离出来。一个可信的星系形成理论必须考虑到CBR的特性，在红移大于1时对星系和星系间介质的观测，以及在相对低红移时星系分布和运动的系统性。研究将继续发展解释这些现象所需的理论和数值技术，并将它们用作膨胀宇宙中结构发展模型的检验。

This group studies gravity physics via experimental and theoretical work on extragalactic astronomy and cosmology. The COBE detection of anisotropy of the 2.7K thermal cosmic background radiation (the CBR) shows the fluctuations are large enough to be studied from the ground and balloons. It seems likely that the character of the anisotropy on angular scales from 30 arc min to the COBE resolution at about 10> will be a strong discriminant for theories of the nature and origin of structure. Work will continue on the development of techniques to map the CBR and the analysis of theories of the origin of the angular fluctuations. The long wavelength part of the CBR spectrum is important as a constraint on the evolution of the intergalactic medium, but the spectrum is not well measured. Research will continue on a systematic approach to deal with the main experimental problem, the separation of the CBR from the emission from our galaxy. A believable theory of galaxy formation must account for the properties of the CBR, the observations of galaxies and the intergalactic medium at redshifts greater than unity, and the systematics of the distribution and motions of galaxies at relatively low redshifts. Research will continue on the development of the theoretical and numerical techniques needed to interpret these phenomena and use them as tests for the models for the development of structure in an expanding universe.