Percolation analysis for cosmic web with discrete points Reporter: Zhang Jiajun Supervisor: Ming-Chung Chu The Chinese University of Hong Kong Date: 2015 Nov 14th Big Bang and The standard cosmology model: CDM model Cosmic pie chart after Planck Big Bang and inflation CMB with small fluctuation Perturbation evolution with gravity Cosmic web and us N-body simulation, what do we do? Klypin, Trujillo-Gomez & Primack 2010 How to compare with observation? N r r [h -1 Mpc] P(k) [(h -1 Mpc) 3 ] k [h/Mpc] Eisenstein et al. ApJ 2005 Definition for percolation and S-bb relation Friend of Friend (FoF) bb: linking length Definition for percolation and S-bb relation S: mass fraction of the largest group S bb S-bb relation CDM model simulated by Gadget2 IC generated using E&H powerspectrum m = 0.3 = 0.7 b = z=0 9 realizations for N=256^3 V=500 (h^-1Mpc)^3 FOF method, S-bb relation S=N largest /N SDSS The Sloan Digital Sky Survey has created the most detailed three- dimensional maps of the Universe ever made, with deep multi-color images of one third of the sky, and spectra for more than three million astronomical objects. --www.sdss.org https://www.youtube.com/channel/UCFDSMno-xnviyexzoOZBrYg Probability Cloud Cluster Expansion Theory S-bb RelationCorrelation Function Not only 2 point! All high order correlation funtion! High order correlation function are different! But its too expansive to calculate high order correlation function. S-bb relation is cheap, easy to do! Develop percolation analysis for cosmic web with discrete points, S-bb relation Propose S-bb relation as a comparison tool to tell the difference between cosmological models We find shortage of mock catalogue, fail to generate correct high order correlation function Percolation analysis: Cheap and Powerful Q & A