Measuring Neutrino Masses and Dark Energy

Transcription

1 Huitzu Tu UC Irvine June 7, 2007 Dark Side of the Universe, Minnesota, June In collaboration with: Steen Hannestad, Yvonne Wong, Julien Lesgourgues, Laurence Perotto, Ariel Goobar, Edvard Mörtsell

2 Motivation Era of precision cosmology: CMB, LSS, SNIa,... Neutrino masses? (0.056 (0.095) ev < m ν < ev, vs 6 ev from lab) Dark energy? (w 1, Ω X 0.7, w(z)?) Breaking the ( m ν,w) degeneracy Baryon acoustic oscillations detected by SDSS Weak lensing (tomography): CFHTLS, SNAP, LSST,... Other observations

3 Neutrino Mass Effects Present matter density: Ω ν h 2 Slow down fluctuation growth: P mν 93.2 ev P lin (k)/p lin (k) 8 Ω ν /Ω m at k k nr [Hu,Eisenstein,Tegmark 97] Late time infall into CDM halos: ρ halo (r, M, z) P nl (k)/p nl (k) 1% at k 1 h Mpc 1 [Abazajian et al. 04; Hannestad,Ringwald, HT,Wong 05]

4 Neutrino Mass Effects (II) no ν s f ν =0 f ν = l(l+1) C l / 2π (µk) P(k) (Mpc/h) no ν s f ν =0 f ν = l k (h/mpc) 10-1 [Lesgourgues,Pastor 06] [Hannestad,HT,Wong 05]

5 Dark Energy Effects Redshift-distance relation: [ [ H 2 (z) = H0 2 Ω m (1 + z) 3 + Ω X exp 3 ]] z 0 dz 1+w(z ) 1+z Structure growth suppression: 2 d2 g d ln a 2 + [5 3 w(a)ω X (a)] for the growth function D(a) = ag(a) dg d ln a + 3 [1 w(a)] Ω X(a)g(a) = 0 Degeneracy with m ν : due to (w X, Ω X ) and ( m ν, Ω m = 1 Ω X ) Baryon Acoustic Oscillations Weak gravitational lensing w SNLS 1st Year BAO Ω M

6 Baryon Acoustic Oscillations (BAO) Oscillations in the photon-baryon fluid before recombination [Peeble,Yu 70;...] Sound horizon at recombination r s (η rec ) 147 Mpc (Ω m h 2 /0.13) 0.25 (Ω b h 2 /0.024) 0.08 Standard ruler : r = z/h(z), r = (1 + z)d A (z) θ [Spergel et al. 06] [Tegmark et al. 06]

7 BAO (II): SDSS Detection in Galaxy Correlation Function ξ( r) δ( x) δ( x + r) ξ(r) = 1 R dk P(k) (2π) 3 sin kr 4πk 2 kr SDSS constraints on dark energy: [Eisenstein et al. 05] parameter WMAP+Main WMAP+LRG w (constant) 0.92 ± ± 0.18 With massive neutrinos we found at z = 0.35 [Goobar,Hannestad,Mörtsell,HT 06] A D V (z) ΩmH 2 0 cz = ( n 0.98) 0.35 ( Ων /Ω m ) ± [Eisenstein et al. 05]

8 Our Current Bounds on m ν : 2 models 11 parameters: ( Ω m, h, Ω b h 2, N ν, w X, n s, α s, τ, Q, b, ) m ν Data mν (95% C.L.) 1: CMB, LSS, SNIa 1.72 ev 2. CMB, LSS, SNIa, BAO 0.62 ev 3. CMB, LSS, SNIa, Ly-α 0.83 ev 4. CMB, LSS, SNIa, BAO, Ly-α 0.49 ev 8 parameters: (..., w X = 1, α s = 0, N ν = 3) Data mν (95% C.L.) 1: CMB, LSS, SNIa 0.70 ev 2. CMB, LSS, SNIa, BAO 0.48 ev 3. CMB, LSS, SNIa, Ly-α 0.35 ev 4. CMB, LSS, SNIa, BAO, Ly-α 0.27 ev [Goobar,Hannestad,Mörtsell,HT 06]

9 Future BAO Surveys Statistical errors σ P P (k) 2π Large volume ( 1 Gpc 3 ) 1 V surveyk 2 k ( ) n P(k) Aim at high redshifts still in linear regime Need spectroscopic redshifts (otherwise 20 larger area) With redshift slicing (5-7 slices, 1 < z < 3) w(z) WFMOS, HETDEX, JEDI, LSST, VADER (?)... Constraints on dark energy: σ(w 0 ) 10% and σ(w 1 ) 20% [Glazebrook,Blake 05; Wang 06;...] Constraints on neutrino masses: a full MCMC to be done [Hannestad,Lesgourgues,Perotto,HT,Wong, in preparation] Model/scenario comparison: with H(z) and D A (z) data [Goobar,Hannestad,Mörtsell,HT]

10 Future BAO Surveys (II) Dependence on fiducial model Sensitivity comparison to weak lensing [LSST Collaboration,

11 Gravitational Weak Lensing (Tomography) Convergence power spetrum C ij l = 9 16 H4 0 Ω2 m χh 0 dχ g i(χ)g j (χ) P( l a 2 χ 2 χ,z) (0.7, -1) (0.7, -1.2) (0.65, -1) (0.65, -1.2)

12 WL Systematics Photometric redshift uncertainties 0.05 n i(z) = R zi+1 ph dz z ph i ph n gal (z)p(z ph z) σ z,z bias [Ma,Hu,Huterer 05] Shear calibration [STEP: Heymans et al. 05] Multiplicative errors 1 2% Ĉ ij l = C ij l (1 + fi + fj) [Huterer,Takada,Bernstein,Jain 05] Additive errors 10 4 Ĉ ij l = C ij l + Cadd l Nonlinear corrections to matter power spectrum 5 10% halo model P nl (k) [Seljak 00; Ma,Fry 00; Smith et al. 03]

13 Our Analysis: Parameters and Surveys WL tomography with 1,3,5,8 bins, 0 < z < 3 Fiducial cosmological model (11 parameters): (w 0 = 1, w a = 0, m ν = 0.07 ev, N eff = 3, Ω c h 2 = , Ω DE = 0.7, Ω b h 2 = , n s = 1, α s = 0, τ = 0.05, σ 8 = 0.9) Systematics: priors on σ z = 0.05 and z bias = 0, f i = 0 Generic WL survey parameters: f sky z 0 γ rms n gal (arcmin 2 ) Wide, LSST-like Deep, SNAP-like

14 Error Forecast for m ν and w WL tomography (wide) + Planck Model Cosmological probes σ( P m ν) 11 parameters Planck only 0.48 ev 11 parameters Planck+Wide ev 11 parameters Planck+Wide ev 7 parameters Planck+Wide ev 7 parameters Planck+Wide ev Planck + Wide-1 + Wide-5 σ(w 0) σ(w a) [Hannestad,Tu,Wong 06]

15 Summary Breaking ( m ν, w) degeneracy m ν from WMAP3 + LSS + SNIa + BAO Future WL tomography constraints: σ( m ν ) = ev CMB lensing σ( m ν ) 0.15 ev (Planck) Cosmological observations pin down m ν to < 0.1 ev, distinguish between normal hierarchy and inverted hierarchy σ(w 0 ) 10%, σ(w a ) 20% from future BAO σ(w 0 ) 3.5%, σ(w a ) 8% from future WL with 5 bins