星系形成环境与宇宙中的空洞

Environmental Effects on Galaxy Formation and the Formation of Voids

本文讨论了初始扰动谱中大尺度负密度扰动对星系尺度扰动峰值的局域密度的影响，以及空洞演化中边界壳层非线性发展的作用。结果表明它们并不能解释空洞的形成。但考虑星系相互作用在可见星系形成中的关键作用，把星系群与星系团的存在作为形成的必要条件时，可以用负密度扰动对星系团和星系群的局域密度的调制，解释３０─６０Ｍｐｃ的空洞形成。对于更大尺度空洞的形成，则必须考虑对标准冷暗物质模型谱作出修正。

The environmental modulation on the local number density of galaxies has been discussed. We found that the modulation is not strong enough to interpret the formation of voids. We also discussed the evolution of the voids and found that the shell crossing or shell density nonlinearly increasing are too late to happen for standard CDM fluctuation spectrum. The interaction of galaxies is important to cause the starbursts in galaxies and in order to have the interaction the existense of groups of galaxies or the clusters of galaxies may be necessary for galaxies to form and become visible. If it is so the environmental modulation on the local number density of groups or clusters of galaxies could be strong enough to form 30─60 Mpc voids.