Park Daeseong, Lee Jounghun
Department of Physics and Astronomy, FPRD, Seoul National University, Seoul 151-747, Korea.
Phys Rev Lett. 2007 Feb 23;98(8):081301. doi: 10.1103/PhysRevLett.98.081301. Epub 2007 Feb 21.
Cosmic voids refer to the large empty regions in the Universe with a very low number density of galaxies. Voids are likely to be severely disturbed by the tidal effect from the surrounding dark matter. We derive a completely analytic model for the void ellipticity distribution from physical principles. We use the spatial distribution of galaxies in a void as a measure of its shape, tracking the trajectory of the void galaxies under the influence of the tidal field using Lagrangian perturbation theory. Our model implies that the void ellipticity distribution depends sensitively on the cosmological parameters. Testing our model against the high-resolution Millennium Run simulation, we find excellent quantitative agreements of the analytic predictions with the numerical results.
宇宙空洞是指宇宙中星系数量密度极低的大片空旷区域。空洞很可能会受到周围暗物质潮汐效应的严重干扰。我们从物理原理出发推导出了一个关于空洞椭圆率分布的完全解析模型。我们将空洞中星系的空间分布用作其形状的一种度量，利用拉格朗日微扰理论追踪空洞星系在潮汐场影响下的轨迹。我们的模型表明，空洞椭圆率分布对宇宙学参数敏感地依赖。通过将我们的模型与高分辨率的千禧年模拟进行对比测试，我们发现解析预测与数值结果在定量上有出色的一致性。
