距离 -- 红移关系与暗能量 詹虎 国家天文台

1. 距离--红移关系与暗能量詹虎 国家天文台 JDEM LSST 南极KDUST BigBOSS Euclid

2. Dark Matter & Dark Energy: Beyond the Standard Model “The acceleration of the Universe is, along with dark matter, the observed phenomenon that most directly demonstrates that our theories of fundamental particles and gravity are either incorrect or incomplete. Most experts believe that nothing short of a revolution in our understanding of fundamental physics will be required to achieve a full understanding of the cosmic acceleration.” – the Dark Energy Task Force, a joint committee to advise DoE, NASA, & NSF on future dark energy research. WIMP? (SUSY: neutralino? gravitino?) Axion? HEPAP 宇宙学常数? Quintessence? Modified Gravity? Back reaction? Brane world? Landscape? 粒子物理宇宙学 NRC NSTC

3. American Association for the Advancement of Science Top 125 Questions in all of science Question #1: What is the universe made of? …at the moment, the nature of dark energy is arguably the murkiest question in physics--and the one that, when answered, may shed the most light. 粒子物理宇宙学

4. Brookhaven National Laboratory California Institute of Technology Carnegie Mellon University Chile Columbia University Cornell University Drexel University Google Inc. Harvard-Smithsonian Center for Astrophysics IN2P3 Labs France Johns Hopkins University Kavli Institute for Particle Astrophysics and Cosmology at Stanford University Las Cumbres Observatory Global Telescope Network, Inc. Lawrence Livermore National Laboratory Los Alamos National Laboratory National Optical Astronomy Observatory Princeton University Purdue University Research Corporation for Science Advancement Rutgers University Space Telescope Science Institute SLAC National Accelerator Laboratory The Pennsylvania State University The University of Arizona University of California, Davis University of California, Irvine University of Illinois at Urbana-Champaign University of Pennsylvania University of Pittsburgh University of Washington Vanderbilt University Particle Physicists Joining Astronomy Projects for Dark Energy – Large Synoptic Survey Telescope Members: LSST 粒子物理宇宙学

5. (Indirect) Evidence for Accelerated Expansion Riess et al. (1998) Perlmutter et al. (1999) The accelerated expansion is an interpretation of the fainter-than-expected supernova apparent magnitudes within the Friedmann-Lemaître-Robertson-Walker framework, and dark energy is a further interpretation of the accelerated expansion. 粒子物理宇宙学

6. Dark Energy or Modified Gravity? Furthermore, the potential fluctuation and curvature fluctuation can differ, leading to inconsistency between lensing and dynamical mass. Clustering Dark Energy Modified Gravity It will be harder to distinguish dark energy from modified gravity, if more degrees of freedom are allowed. See, e.g., discussions about generic modified gravity and dark energy with entropy and shear stress perturbations in Bertschinger & Zukin (0801.2431). Well motivated models are needed. 粒子物理宇宙学

7. Dark Energy Probes Dark Energy Task Force report(Albrecht et al., astro-ph/0609591) 粒子物理宇宙学

8. Detecting Supernovae 粒子物理宇宙学

9. Constraining Dark Energy with Type Ia Supernovae SN measures relative luminosity distance: Zhan (2006) Dark energy equation of state: w = w0 + wa (1 - a) SN constraints on w0 & wa depends on the prior on the mean curvature of the universe, because the sensitivity of the luminosity distance to curvature is somewhat degenerate with the sensitivity to wa. Linder (2005) 粒子物理宇宙学

10. Impact of Supernova Evolution SNAP SN absolute magnitude is assumed to evolves as e1z + e2z2. In the left figure, SNAP does not include ground SNe, but does include Planck priors. The prior on e1 and e2 is 0, 0.02, 0.08, and none from inside out. One cannot achieve s(e1) = s (e2) = 0.015 (as assumed in the Dark Energy Task Force report) by a joint parameter fitting. Such priors must come from direct observations. 粒子物理宇宙学

11. CMB temp. fluctuations (WMAP) Angular diameter distance RS = DqDA RS~150 Mpc BAOs in multipole space (Sound horizon at recombination) Galaxy angular power spectrum Baryon Acoustic Oscillations Imprints on the matter power spectrum (White 2005) = cDz/H RedshiftDistortion  growth rate  testing gravity DLS survey 粒子物理宇宙学

12. Acoustic Perturbations before Recombination From Daniel Eisenstein Curvature perturbations  pressure imbalance in photon—baryon fluid  sound waves travel at speed ~ c /√3 before recombinationand ~ 0 thereafter  comoving sound horizon (RS ~ 150 Mpc) freezes  excess correlation of density fluctuations at 150 Mpc  excess correlation of galaxies at 150 Mpc. 粒子物理宇宙学

13. From CMB to the Large-Scale Structure WMAP media @ map.gsfc.nasa.gov 粒子物理宇宙学

14. dg(x+Dx) Dx dg(x) Deep Lens Survey, Tyson & Wittman Correlation Function Power Spectrum Galaxy Correlations & Power Spectra Baryon Acoustic Oscillations SDSS LRGs Eisenstein et al (2005) Baryon Acoustic Oscillations in multipole space Angular PS Zhan (2006) 粒子物理宇宙学

15. Gravitational Lensing sheared image a = 4GM/bc2 DS DLS b shear q DLS g ~ q = 4GM/bc2 DS Cosmology changes geometric distance factors Gravity & Cosmology change the growth of mass structure 粒子物理宇宙学

16. 粒子物理宇宙学

17. Strong Lensing by Cluster of Galaxies The shear correlation originates from correlation of the foreground mass. Note: the cosmic shear, i.e., weak lensing signal, is much weaker! 粒子物理宇宙学

18. g(q+Dq) Dq g(q) 1.1o1.1o simulated shear field by Hamana Correlation Function Power Spectrum Shear Correlations & Power Spectra Hoekstra et al (2005) Song & Knox (2004) 粒子物理宇宙学

19. D(z) and G(z) from LSST BAOs and WL Zhan et al. (2009) • BAO distance errors are smaller than WL ones. • BAO growth constraints are from the nonlinear power spectrum. • WL growth rates are not affected by other cosmological parameters. 粒子物理宇宙学

20. Complementarity between BAO and WL • Projection of errors of distance eigenmodes onto w0‒wa space. • 5 WL distance eigenmodes account for most of the WL constraints on w0 & wa. • BAO & WL are highly complementary. 粒子物理宇宙学

21. Modification to the Lensing Potential gGR≈ 0.55 dg= g - gGR Amendola et al. (2008) Projected 68% likelihood contours of the parameter describing the effective modification to the lensing potential, and the growth index for weak lensing surveys from a full sky survey with median z = 0.9 and surface densities of sources of 35, 50 and 75 galaxies per arcminute. 粒子物理宇宙学

22. 谢谢！ 粒子物理宇宙学