Beyond CDM: Status and Prospects from Redshift Surveys Beth Reid - PowerPoint PPT Presentation

Beyond Λ CDM: Status and Prospects from Redshift Surveys Beth Reid Cosmology Data Science Fellow UC Berkeley Center for Cosmological Physics/ Lawrence Berkeley National Lab in collaboration with the SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS) image courtesy Chris Blake and Sam Moorfield Thursday, January 15, 2015

The observable universe to scale* SDSS galaxies SDSS Ly- α z < 0.7 z ≈ 2.4 z=0.7 z=1091 growth of fluctuations ~1000x BAO standard ruler = 151.4 ± 0.66 Mpc [Planck XVI] SDSS image courtesy Anze Slosar Beth Reid Oslo: Beyond Λ CDM Thursday, January 15, 2015

Questions to address • How do we and how should we extract cosmological information from these CMB and LSS maps? • What have we learned? • Where/how should we look next? Beth Reid Oslo: Beyond Λ CDM Thursday, January 15, 2015

Three regimes of LSS Highly nonlinear/ Linear Mildly nonlinear galaxy formation > 30 h -1 Mpc 2 - 30 h -1 Mpc < 1 h -1 Mpc Beth Reid Oslo: Beyond Λ CDM Thursday, January 15, 2015

Three regimes of LSS Highly nonlinear/ galaxy formation < 1 h -1 Mpc • “Too big to fail”, etc. • Galaxy cluster cosmology • Covered in other talks Beth Reid Oslo: Beyond Λ CDM Thursday, January 15, 2015

Three regimes of LSS Linear > 30 h -1 Mpc • Physics is linear • Fluctuations are Gaussian • (Almost) all information contained in 2-point correlations • Λ CDM passes stringent tests with a few intriguing 2-2.5 σ discrepancies Beth Reid Oslo: Beyond Λ CDM Thursday, January 15, 2015

CMB-LSS consistency: spectrum of matter fluctuations • Planck tightly constrains the spectrum of fluctuations in the “linear” regime of LSS, k = 0.01 - 0.2 h Mpc -1 . PRELIMINARY! [source: Efstathiou @ Ferrara] Beth Reid Oslo: Beyond Λ CDM Thursday, January 15, 2015

CMB-LSS consistency: spectrum of matter fluctuations • Best fit Planck model compared to halo P(k) from SDSS-II LRGs [Reid et al 2010] Planck best fit χ 2 = 40.4/40 dof vs 40.0 (LRG only) Beth Reid Oslo: Beyond Λ CDM Thursday, January 15, 2015

CMB-LSS consistency: spectrum of matter fluctuations • Similarly good agreement with SDSS-III BOSS DR11 [Beutler et al. 2014] Beth Reid Oslo: Beyond Λ CDM Thursday, January 15, 2015

CMB-LSS consistency: spectrum of matter fluctuations • CMB-LSS CDM TeVeS consistency supports CDM as the backbone of structure formation, with no (little) DE clustering on these scales Dodelson, arXiv:1112.1320 Beth Reid Oslo: Beyond Λ CDM Thursday, January 15, 2015

CMB-LSS consistency: expansion history • The CMB calibrates the baryon acoustic oscillation (BAO) standard ruler [s BAO = 147.5 ± 0.6 Mpc, Planck XVI] Beth Reid Oslo: Beyond Λ CDM Thursday, January 15, 2015

BAO in SDSS-III BOSS CMASS sample: 1% distance constraint at z=0.57 s 2 ξ (s) P(k)/P smooth (k) BOSS collab., MNRAS 441, 24 (2014) Beth Reid Oslo: Beyond Λ CDM Thursday, January 15, 2015

CMB-LSS consistency: expansion history • 1% Planck Λ CDM prediction and 1% galaxy BAO measurement PRELIMINARY! agree! [source: Efstathiou @ Ferrara] Beth Reid Oslo: Beyond Λ CDM Thursday, January 15, 2015

CMB-LSS tension: Ly- α BAO • ≈ 2.5 σ tension with flat Λ CDM • Offset in D A -D H plane difficult to produce in a physical model • See arXiv:1411.1074 for joint examination of all BAO measurements and Delubac et al., arXiv:1404.1801 many cosmological models Beth Reid Oslo: Beyond Λ CDM Thursday, January 15, 2015

Clustering anisotropy provides a measurement of the peculiar velocity amplitude (f σ 8 ). ξ (r ⊥ , r ∥ ) r ∥ (h -1 Mpc) angle-average anisotropy r ⊥ (h -1 Mpc) s (h -1 Mpc) BOSS DR11, Samushia, BR, et al. 2013 Beth Reid Oslo: Beyond Λ CDM Thursday, January 15, 2015

CMB-LSS consistency: Growth rate of stucture with RSD • *Assuming* Planck Λ CDM expansion history, RSD measurements prefer lower f σ 8 than Planck at ≈ 1.9 σ . Beth Reid Oslo: Beyond Λ CDM Thursday, January 15, 2015

RSD constrains modified gravity • RSD measurements rule out nonlocal gravity at 7.8 σ . Dodelson and Park, PRD 90, 043535 (2014) Beth Reid Oslo: Beyond Λ CDM Thursday, January 15, 2015

Three regimes of LSS Mildly nonlinear 2 - 30 h -1 Mpc • Under-valued -- lots of S/N available! • non-Gaussian -- what should we measure? • Beyond reach of perturbative models (simulations required) • Requires somewhat detailed statistical description of galaxy <-> matter connection • Particularly interesting for modified gravity models(?) Beth Reid Oslo: Beyond Λ CDM Thursday, January 15, 2015

Example 1: Constraining the growth rate in the nonlinear regime ξ (r ⊥ , r ∥ ) r ∥ (h -1 Mpc) r ⊥ (h -1 Mpc) BOSS DR11, Samushia, Reid et al. 2013 Reid et al. 2014 Beth Reid Oslo: Beyond Λ CDM Thursday, January 15, 2015

Example 1: Constraining the growth rate in the nonlinear regime • Anisotropic clustering reflects two competing effects: A. Pairwise infall from gravitational attraction B. small-scale ( ≈ incoherent) velocity dispersion • Must marginalize over galaxy <-> matter mapping to extract A. Reid et al. 2014 • Simulations required for theoretical prediction. Beth Reid Oslo: Beyond Λ CDM Thursday, January 15, 2015

Constraining the growth rate in the nonlinear regime: model tests Beth Reid Oslo: Beyond Λ CDM Thursday, January 15, 2015

Constraining the growth rate in the nonlinear regime: 2.5x tighter constraint! • DR11 large scales: f σ 8 = 0.447 ± 0.028 • DR10 small scales: f σ 8 = 0.450 ± 0.011 • Planck Λ CDM prediction: f σ 8 = 0.480 ± 0.010 Beth Reid Oslo: Beyond Λ CDM Thursday, January 15, 2015

Modified gravity implications: effects on P(v 12 ,r) ~1-2 h -1 Mpc enhancement in v(r) at r =5 h -1 Mpc for both f(R) and Galileon simulations [Zu et al. 2013] *SHOULD* be easily ruled out by our measurements (2.5% accuracy!) but modified gravity simulations needed for a quantitative comparison Map to redshift space: Beth Reid Oslo: Beyond Λ CDM Thursday, January 15, 2015

Example I1: Combining galaxy-galaxy lensing and galaxy clustering Lensing Clustering Mandelbaum et al. 2012 Beth Reid Oslo: Beyond Λ CDM Thursday, January 15, 2015

Example I1: Combining galaxy-galaxy lensing and galaxy clustering lensing + clustering • Focus on R ≳ 3 h -1 Mpc, where cross-correlation coefficient ≈ 1 (corrections perturbative) • Constrains σ 8 Ω m0.6 • Should also be interesting for WMAP Λ CDM modified gravity models Mandelbaum et al. 2012 Beth Reid Oslo: Beyond Λ CDM Thursday, January 15, 2015

Example I1I: Bayesian inference for LSS Leclercq & Wandelt, arXiv:1410.1546 • Jointly constrains 3d density field, power spectrum, and galaxy biases • What else can we learn from this approach? • See also Ata, Kituara, and Muller Beth Reid Oslo: Beyond Λ CDM Thursday, January 15, 2015

Conclusions • Linear regime LSS probes are generally consistent with Planck Λ CDM prediction, though intriguing “tensions” exist (Ly- α BAO; σ 8 from lensing/RSD/clusters at low redshift) • Mildly nonlinear regime offers more signal to noise, requires simulations for modeling; relatively unexplored Beth Reid Oslo: Beyond Λ CDM Thursday, January 15, 2015