标题： 欧拉-泊松-牛顿方法在宇宙学中的应用 显示英文标题

标题： Euler-Poisson-Newton approach in Cosmology

摘要： 本讲座为我们提供了牛顿方法，用于解释两个仍被讨论的宇宙学观测现象：大尺度流动和星系分布中的泡沫状结构。 对于第一个现象，我们模拟了所有平面畸变的运动，除了两种类型的平面轴向畸变（有或没有旋转），当引力源的空间分布是均匀的时候。 这为我们提供了一种替代模型，该模型不假设存在类似巨大吸引子的引力结构作为大尺度流动的起源。 对于第二个现象，该模型描述了一个由球形空洞组成且周围有均匀尘埃分布的各向同性宇宙。 它不同于通常将空洞解嵌入宇宙学背景解的方式，而是流体力学的整体解。 空洞扩张的一般行为显示出巨大的初始爆发，最终逐渐冻结以匹配哈勃扩张。 虽然壳层上对哈勃定律的修正因子在早期阶段对宇宙学常数的依赖较弱，但它使我们能够显著区分红移z ~ 1.7附近的宇宙学模型。 球形空洞的放大效应随着密度参数和宇宙学常数的增加而增加。 一个有趣的特点是，在空间闭合的弗里德曼模型中，空区域被扫除，这为我们提供了稳定性准则。 显示英文摘要

摘要： This lecture provides us with Newtonian approaches for the interpretation of two puzzling cosmological observations that are still discussed subject : a bulk flow and a foam like structure in the distribution of galaxies. For the first one, we model the motions describing all planar distortions from Hubble flow, in addition of two classes of planar-axial distortions with or without rotation, when spatial distribution of gravitational sources is homogenous. This provides us with an alternative to models which assume the presence of gravitational structures similar to Great Attractor as origin of a bulk flow. For the second one, the model accounts for an isotropic universe constituted by a spherical void surrounded by a uniform distribution of dust. It does not correspond to the usual embedding of a void solution into a cosmological background solution, but to a global solution of fluid mechanics. The general behavior of the void expansion shows a huge initial burst, which freezes asymptotically up to match Hubble expansion. While the corrective factor to Hubble law on the shell depends weakly on cosmological constant at early stages, it enables us to disentangle significantly cosmological models around redshift z ~ 1.7. The magnification of spherical voids increases with the density parameter and with the cosmological constant. An interesting feature is that for spatially closed Friedmann models, the empty regions are swept out, what provides us with a stability criterion.