Title：Tomographic Alcock-Paczynski test: promising results from SDSS-III BOSS galaxies
Speaker：Xiao-Dong Li (Sun Yat-Sen University)
Abstract：The distribution of the observed galaxies is anisotropic, due to two reasons. The RSD effect (galaxy peculiar motion), and the Alcock-Paczynksi (AP) effect. AP appears when an incorrect cosmological theory is assumed for transforming galaxy redshifts to comoving distances. We find the anisotropy produced by AP has larger redshift evolution than RSD, and make use of this fact to probe AP and avoid the large effect of RSD.
We apply this concept to the 1.4 million SDSS-III BOSS galaxies lying in 0.15<z<0.7. We split the galaxies into six redshift bins, measure the anisotropic 2-point correlation function in each bin, and assess the redshift evolution. We estimate the systematics from the Horizon Run 4 N-body simulation and subtract it in the analysis. The obtained cosmological constraints are as good as the mainstream cosmological probes of SNIa, CMB, and BAO. Combining all method, we obtained Ωm = 0.301 ± 0.006, w = -1.054 ± 0.025; inclusion of our method reduces the uncertainties by 35%. We expect our method play an important role in the future galaxy redshift surveys.