紅位移誤差對空間相關函數之影響及史隆數位巡天計畫星系團之空間相關函數

Abstract

當前進行中的大型觀測計畫，例如泛星計畫（Panoramic Survey Telescope And Rapid Response System, Pan-STARRS）等，將可以提供大量的高紅移星系之觀測資料，但這些星系利用光度測量之紅移（photometric redshift）的誤差比光譜紅移（spectroscopic redshift）來得更大，在測量星系及星系團空間相關函數（correlation function）時，一般利用去投射法（deprojection method）來去除紅移誤差的影響。本篇論文中，我們測量去投射法在不同紅移誤差及視場（field of view）大小之下的效能，我們發現當視場大於4.5 平方度以及星系紅移誤差小於0.07時，去投射法能夠得到真正的空間相關函數。我們也測量了史隆數位巡天計畫（Sloan Digital Sky Survey, SDSS）之星系團之空間相關函數，及其與星系團質量及顏色之關係，以便和將來測得之高紅移星系團之空間相關函數做比較。

The large photometric surveys, like Pan-STARRS, will provide vast data sets of galaxies and groups to investigate the large-scale structure. While using these data sets, one needs to deal with the large redshift uncertainties. In this thesis, we study the impact of redshift uncertainties to the clustering of galaxies. Using Pan-STARRS light-cone simulation with different redshift errors and sample sizes, we test the performance of a ‘deprojection method’ used to eliminate the redshift distortion from galaxy and group clustering. We find that the deprojection method can recover the real-space correlation function well from photometric samples with area ≥ 4.5 deg2 and redshift error Δz≤ 0.07. For sample covering 2.7 deg2 and 0.9 deg2, this method is valid for Δz≤ 0.03 and Δz≤ 0.01, respectively. We also investigate the mass and color dependence of group clustering for SDSS DR4 group catalogue. Our results show that (1) more massive groups show stronger clustering amplitude, in agreement with previous studies, (2) low-mass groups with blue central galaxies are more strongly clustered than groups with red central galaxies, and (3) for massive groups, groups with red central galaxies are more strongly clustered. We compare our results of color dependence to that obtained by Wang et al. and Berlind et al, and discuss the discrepancy.