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: ΛCDM 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 ΛCDM model simulated by Gadget2 IC generated using E&H powerspectrum Ω m = 0.3 Ω Λ = 0.7 Ω 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

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 it’s 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