N-body simulations of supercluster dynamics to test the viability of large scale structure as a probe of dark energy and dark matter.

摘要

Many parameters of modern cosmology have been determined to incredible precision at present, including tight constraints on two rather mysterious components of the Universe, dark matter and dark energy. Large Scale structure may be uniquely able to place constraints on both of these components, particularly structures that are loosely gravitationally bound. In such structures, the effects of dark energy's outward push is only slightly less than gravity's inward pull, giving the best chance for detection of dark energy in their dynamics. This work aims to answer whether these structures could potentially serve as a laboratory for studying dark energy, by simulating the dynamics of superclusters both including and excluding its effects. Also, by comparing simulation results with an observational dynamical analysis, dark matter content and possibly the effects of dark energy can be constrained. For this purpose four potentially bound superclusters were identified: the Aquarius, Corona Borealis, Microscopium, and Shapley superclusters. Their dynamics were simulated with N-body software written by the author.;It is shown that there is a difference in the line-of-sight velocity dispersions of superclusters depending on whether the effects of dark energy are included or not, but this difference is small enough that it would not be detectable due to observational uncertainties. A new method of supercluster mass estimation, named SCM+FP, is presented, combining knowledge of the dynamics and the spherical collapse model to determine the mass. Also, a new analytical model for the extent of gravitationally bound structure is presented, arising from a simple modification of the spherical collapse model which is supported by simulation results. Further results include the most conclusive evidence to date of extended bound structure in the Corona Borealis supercluster along with evidence that there is extended bound structure in the Shapley supercluster, each with a core of five clusters. There is also evidence that both the Aquarius and Microscopium superclusters contain bound pairs of clusters. In the end, it is shown that large scale structure likely has more of a role to play in constraining the distribution of dark matter, rather than placing constraints on dark energy.