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 Acceleration of Universe  Background level  Evolution of expansion: H(a), w(a)  degeneracy: DE & MG  Perturbation level  Evolution of inhomogeneity:

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Presentation on theme: " Acceleration of Universe  Background level  Evolution of expansion: H(a), w(a)  degeneracy: DE & MG  Perturbation level  Evolution of inhomogeneity:"— Presentation transcript:

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2  Acceleration of Universe  Background level  Evolution of expansion: H(a), w(a)  degeneracy: DE & MG  Perturbation level  Evolution of inhomogeneity: G(a), G(a, k), Phi, Psi…  Smoothing energy component or modified gravity?  Scalar field  F(R), DGP, TeVeS,

3  Growth of LSS  Expansion: H(a)  consistency relation: H_growth vs. H_expansion  Metric perturbation:

4  Modified Gravity  H(a)  Modified Poisson equation.  G_eff  Parametrization  Growth index (scale-independent)

5  convergence power (cross) spectrum  rich information (power spectrum, cross-spectrum) ‏  photo-z error

6  standard ruler  Spectroscopic survey  δ field  Growth factor G(z)  v field  (redshift distortion)  β~ dlnG/dlna

7 2009 XuGuangqi-Galieo conference 7 A sensitive measure of gravity Guzzo et al. 2008 Acquaviva et al. 2008 Spectroscopic redshift surveys Measure beta from the anisotropy Measure galaxy bias Obtain f Current measurements

8  Standard Candle  variation of SN peak L (after the standardization) ‏  photo-z error (without spectrum) ‏  z-dependent peak L (e.g. SN evolution, extinction) ‏

9  mass of clusters are not measured directly (except for WL) ‏  complex baryon physics (hydrodynamics, galaxies formation) ‏  SZ flux decrement, X-ray temperature, gas mass  mass selection function

10  number distribution  angular density

11  BAO  Spectroscopic survey  Photometric survey

12  Supernovae  200 SNIa/year/deg^2 available for z<1.2 (limit for ground experiment) ‏  SN1: 50 /y/deg^2  SN2: 100 /y/deg^2  photo-z error  N_c: # of spectra for calibration  Systematics (Nuisance parameters) :  absolute magnitude  quadratic offset

13  Weak Lensing (same as Sun lei & Zhao Gongbo) ‏

14  Clusters Count

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16  Genus  Gaussian fluctuation:  3D (δ)  2D (weak lensing, κ)

17  Resistant against:  Bias, redshift distortion, weak nonliearity.  In GR  Invariant amplitude.  Standard ruler  In MG  Introduce new scale-dependence  time-varying  Complementary to growth rate of matter fluctuation.  Sensitive to scale-dependent modification at sub-horizon scale.

18  Fisher calculation:

19 Testing the (generalized) Poisson Equation 2009 XuGuangqi-Galieo conference 19 = Gravitational lensing from peculiar velocity ? Galaxy redshifts to recover redshift information (2D ->3D)

20 2009 XuGuangqi-Galieo conference 20 LCDM f(R) DGP MOND/TeVeS ZPJ et al. 2007 E G will be measured to 1% level accuracy within two decades Promising to detect one percent level deviation from general relativity+canonical dark energy model (if systematics can be controlled)!

21 2009 XuGuangqi-Galieo conference 21 ZPJ et al. 2008 eta can be measured to 10% accuracy. Errors in eta is larger than errors in E_G Even so, eta can have stronger discriminating power, in some cases. η of DGP differs significantly from that of LCDM. (E G of DGP is very close to that of LCDM.) eta and E_G are complementary DGP with high Omega_m SKA forecast DGP MOND TeVeS dark energy with anisotropic stress One can further construct an estimator of Lensing: Φ-Ψ; Peculiar velocity: Ψ

22 Thanks


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