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Five Ways to Measure Dark Energy

Five Ways to Measure Dark Energy. Yongzhong Xu Los Alamos National Laboratory. Dark Matter & Dark Energy CCAST July 4-8th, 2005. #1 Science Breakthrough in 1998. #1 Science Breakthrough in 2003. Outline. What do we know about dark energy?

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Five Ways to Measure Dark Energy

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  1. Five Ways to Measure Dark Energy Yongzhong Xu Los Alamos National Laboratory Dark Matter & Dark Energy CCAST July 4-8th, 2005

  2. #1 Science Breakthrough in 1998 DM&DE,Jul 4-8

  3. #1 Science Breakthrough in 2003 DM&DE,Jul 4-8

  4. Outline • What do we know about dark energy? • How to constrain the dark energy density? (also in Prof. Fan’s talk) • CMB + LSS (power spectra), CMB x LSS (ISW) • Type Ia Supernovae (SNAP) • Cluster physics (abundance evolution, SZ+X-ray, lensing, fgas) • Gamma-ray bursts • Galaxy voids? • Summary DM&DE,Jul 4-8

  5. What we know? • Dark Energy exists • Indirect evidences (WMAP+2dFGRS, SDSS+WMAP) • Direct evidences (Integrated Sachs-Wolfe Effect) • WMAP x SDSS (Scranton etal.) • WMAP x 2MASS • Dark Energy Density (~70%) • w ~ -1 • Others? Nothing! DM&DE,Jul 4-8

  6. First result from WMAP Spergel et al., 2003 DM&DE,Jul 4-8

  7. w from WMAPext+2dfGRS DM&DE,Jul 4-8

  8. w from SDSS+WMAP Tegmark etal. 2004 DM&DE,Jul 4-8

  9. W from SDSS+WMAP DM&DE,Jul 4-8

  10. ISW Effect Hu 2004 DM&DE,Jul 4-8

  11. Detect ISW Effect Scranton et al. 2003 DM&DE,Jul 4-8

  12. Type Ia Supernovae (SNAP) DM&DE,Jul 4-8

  13. What SNAP Expects DM&DE,Jul 4-8

  14. Evolution of Cluster Abundance • Clusters in current redshfit surveys • Finding clusters in SDSS and/or 2dFGRS • Evolution of cluster abundance • Clusters in future surveys • LAMOST • Dark Energy Survey (one of the proposals for JDEM) DM&DE,Jul 4-8

  15. Finding Clusters in SDSS • Voronoi Tessellation • More than 3,000 clusters found in DR3 DM&DE,Jul 4-8

  16. Dark Energy Survey DM&DE,Jul 4-8

  17. Dark Energy Survey DM&DE,Jul 4-8

  18. Gamma-Ray Bursts Ghirlanda, Ghisellini, & Lazzati, 2004 Dai, Liang, & Xu, 2004 Atteia et al. 2003 DM&DE,Jul 4-8

  19. Galaxy Voids • 95% volume • Low mass, underdensity • About 1,000 voids found in SDSS DR3 • More dark energy in voids? DM&DE,Jul 4-8

  20. Summary • There are various methods to constrain the dark energy density and the equation of state w • Hopefully, we can constrain the evolution of w(z) using the current and future data • Can we use voids to measure dark energy? DM&DE,Jul 4-8

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