Blake Chris, Wall Jasper
Astrophysics, Nuclear and Astrophysics Laboratory, University of Oxford, UK.
Nature. 2002 Mar 14;416(6877):150-2. doi: 10.1038/416150a.
The motion of our Galaxy through the Universe is reflected in a systematic shift in the temperature of the cosmic microwave background-because of the Doppler effect, the temperature of the background is about 0.1 per cent higher in the direction of motion, with a correspondingly lower temperature in the opposite direction. This effect is known as dipole anisotropy. If our standard cosmological model is correct, a related dipole effect should also be present as an enhancement in the surface density of distant galaxies in the direction of motion. The main obstacle to finding this signal is the uneven distribution of galaxies in the local supercluster, which drowns out the small cosmological signal. Here we report a detection of the expected cosmological dipole anisotropy in the distribution of galaxies. We use a survey of radio galaxies that are mainly located at cosmological distances, so the contamination from nearby clusters is small. When local radio galaxies are removed from the sample, the resulting dipole is in the same direction as the temperature anisotropy of the microwave background, and close to the expected amplitude. The result therefore confirms the standard cosmological interpretation of the microwave background.
我们的银河系在宇宙中的运动反映在宇宙微波背景辐射温度的系统性偏移上——由于多普勒效应，在运动方向上背景温度约高0.1%，而在相反方向温度相应较低。这种效应被称为偶极各向异性。如果我们的标准宇宙学模型是正确的，那么在运动方向上遥远星系的表面密度增强也应呈现出一种相关的偶极效应。寻找这一信号的主要障碍是本超星系团中星系分布不均，这掩盖了微弱的宇宙学信号。在此，我们报告在星系分布中探测到了预期的宇宙学偶极各向异性。我们使用了一项对主要位于宇宙学距离的射电星系的巡天观测，因此来自附近星系团的污染较小。当从样本中去除本地射电星系后，得到的偶极与微波背景辐射的温度各向异性方向相同，且接近预期幅度。因此，这一结果证实了对微波背景辐射的标准宇宙学解释。
