The Influence Of Redshift Distortion On Cosmic Void

Cosmic voids are low-density region of the universe which surrounded by high-density structures,and they are used to explore evolution of galaxies,constrain neutrino mass and cosmological parameters owing to their character.However,the redshift space distortion will affect the measurement of the real void structure,and then impact on extracting the true information of the universe in the observation.Therefore,we need to explore the effect of redshift distortion on voids by simulation data,so that understanding the bias of voids' properties from real space to redshift spaceIn chapter 1,We will indicate the basic theories of the large-scale distribution of matter in the universe,including the standard cosmological model,the linear and non-linear evolution of cosmic matter,and collapse model?In chapter 2,We will introduce the origin and effection of redshift space distortion,show the linear theory of redshift space and real space,and introduce effection of redshift distortion on cosmological measurements.In chapter 3,We will introduce the application of voids on cosmology,theoretical models of void structures,void algorithms,problems in void research,and show the results of void dynamics classification.We subdivide cosmological voids into "expanded" and"collapsed",and turn up that the proportion of "expanded" voids increases with size,the tendency will weaken with the decrease of cosmological redshift,and the mean effective radius of "expanded" voids is about 20%larger than the "collapsed"voids;we found that the "collapsed" voids wall are thick,these voids are more likely to be inserted in high-density area of universe.the "expanded" voids' wall are thinner than "collapsed" voids,these voids are prefer to existing in the low-density region of universe,the evolution path and ellipticity of "expanded" voids are different from the"collapsed" voids.In chapter 4,We will introduce the matching algorithm of voids,and show the effect of redshift distortion on cosmic voids.We found that the number of small voids is less and large voids is more in real space compared redshift space,and about half of voids in the redshift space cannot correspond to real space by matching algorithm.For matched voids,the influence of redshift distortion on the density profile of "collapsed"void is more obvious,but there are some discrepancy of redshift distortion effect on different size voids owing to voids' member galaxies velocity.For unmatched voids,their mean density profile is higher than the matched in redshift space;in real space,the mean density profile and mean velocity profile of unmatched voids are different from matched voids.In chapter 5,We will summarize the results of the current work and prospects for the follow-up research.