Dark Energy Effects on CMB & LSS

Dark Energy Effects on CMB & LSS The 2nd KIAS Workshop on Cosmology and Structure Formation Seokcheon (碩天 large sky) Lee Institute of Physics, Academia Sinica KIAS WORKSHOP

Outline • Observable Impact of DE • BAO, CL, SN, WL • (Im)Perfect Dark Energy Fluid • Effects on CMB and Matter Power Spectrum • Summary KIAS WORKSHOP

Observable Impact of DE • Modification of z–d relation : Baryon Acoustic Oscillations (BAO, R.Kron), SuperNova (SN, G-C Liu), [δD] • Effects on growth of structures : Galaxy CLustering counting (CL, Z.Zheng), Weak Lensing (WL, Sejong Univ), ISW effect (C.G.Park) KIAS WORKSHOP

Observations & Measurements KIAS WORKSHOP

H(z) & δ(z) • Evolution of Background • From WMAP data we can find zeq ~ 5000 • Flat Universe is preferred by WMAP. i.e. Ωk = 0 • Density fluctuation on small scales (sub-horizon scale) KIAS WORKSHOP

r(z) and dV(z) • FRW metric • Volume element • Proper distance • Comoving coordinate KIAS WORKSHOP

Imperfect DE Fluid • Cosmological fluid • Adiabatic and entropic sound speed (J-C Hwang) • Dark energy rest frame • Anisotropic stress of DE KIAS WORKSHOP

Effects of σ on δ & θ • For large scale source term : -(1+ω)(c_s^2-ω)θ/k^2 • ω = -0.8 • Dominate metric source term and derive δ to smaller values • k = 1.3 · 10^{-4} Mpc^{-1} • (c_s^2, c_vis^2) = (0,0), (0.6,0),(0,0.6),(0.6,0.6) • δ gets smaller when DE dominate (solid lines) • Θ increases (dashed lines) • ISW id enhanced as c^2 increases KIAS WORKSHOP

ISW Effects • C_{vis}^2 : 1.0, 0.1, 0.01, 0.001, 0 • MD : total density grows in order to Φ,Ψ = const. KIAS WORKSHOP

Matter Power Spectrum • C_{vis}^2 = 1.0 • Solid line : w=-1.2, c_s^2=1.0 Dash-dotted : w=-0.8,c_s^2=0 Dashed : w=-1.2 c_s^2=0 Thick : w=-0.8, c_s^2=1.0 KIAS WORKSHOP

Summary • As c_{vis}^2 ↑, δ↓ , θ↑, H/k^2(1+ω)θ↑ • As c_{vis}^2 ↑, ISW ↑ • Effects on MPS occurs only at large scales • CMB’s only sensitive to <ω> • Correlation to others BAO, CL, D(g), WL… • Bispectra (? Y. Suto) • DARK ENERGY IS NOWHERE! KIAS WORKSHOP

Dark Energy Effects on CMB & LSS