COMING HOME

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COMING HOME. Michael S. Turner Kavli Institute for Cosmological Physics The University of Chicago. Some Cosmological Observations from Afar. No Chinks in “The New Cosmology”. WMAP + SDSS + 2dF + HST Key Project + DASI + ACBAR + CBI + t 0 + SNe … Smaller error bars, consistency remains - PowerPoint PPT Presentation

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  • COMING HOMEMichael S. TurnerKavli Institute for Cosmological PhysicsThe University of Chicago

  • Some Cosmological Observations from Afar

  • No Chinks in The New CosmologyWMAP + SDSS + 2dF + HST Key Project + DASI + ACBAR + CBI + t0 + SNe Smaller error bars, consistency remains(n): 0.1 to 0.02; (0): 0.03 to 0.01; (w): 0.2 to 0.1Hubble constant has been constant for 5 years! H0 = 72 7 km/s/MpcLooking better than ever almost ready for a real name!(i.e., CDM + Dark Energy + Inflation)

  • Precision Cosmology is Harder than Theorists projectionsBits & bitesl = 2 to 5Optical depth: = 0.17 to 0.09

  • Serious testing of Inflation has begun Key PredictionsFlat UniverseAlmost scale-invariant, Gaussian perturbations: |(n-1)| ~ 0.1 and |dn/dlnk| ~ 0.001Gravity waves: spectrum, but not amplitude predicted

    Key Results0 = 1.0 0.01(n-1) = 0.96 0.017*; dn/dlnk = -0.1 0.05; no evidence for nonGaussianityr < 0.55 (95% cl)**Depends significantly upon the priors assumed

  • Cosmic AccelerationDark Energy Evidence for cosmic acceleration has gotten stronger (HST, CFHTLS, Essence, WMAP, XMM/Chandra)Still no understanding theorists continue to explore phase spaceNo evidence that dark energy is not the energy of the quantum vacuumw = -1 0.1 (from 0.2); no evidence for time variationVery significant probes on the horizon:JDEM, LSST,

  • Loose Ends Precision test (few percent) using baryon density: BBN (D/H) vs. CMB (odd/even) unrealizedConsistency of BBN light element predictions (He D Li tension)8: lack of consistencyCosmic variation of Excess power at l ~ 2000LSND 4th neutrinoDAMA, e+ excess,

  • What Do We Really Know About Cosmic AccelerationCharles A. Shapiro & Michael S. Turner,astro-ph/0512586

  • Much of What We Know About Cosmic Acceleration Traces to Model Assumptions (CDM, wCDM)CDM, wCDM are much better fits than models w/o dark energy (CDM or OCDM) but, the acceleration history is fixed: recent acceleration, past decelerationIn addition, the correctness of Friedmann equation is assumed (what if gravity theory is part of the solution?)

  • Assumptions & InputsMetric theory of gravity with Robertson-Walker metricFriedmannless analysisReiss et als Gold Set of Supernovae (adding CFHT Legacy doesnt change things much)Flat Universe (can be relaxed more later)Piecewise constant acceleration historiesPrincipal component analysis for q(z)

  • Robust ConclusionsUniverse may not be accelerating today: Model with deceleration since z = 0.3 is acceptable at 10% clVery strong evidence that Universe once accelerated (5) (from best determined mode)Strong evidence that q(z) was larger in the past (other well determined modes)Weak evidence that Universe decelerated in the past

  • 6 Most Well Determined Principal ComponentsDecelerationRedshift

  • CDM2 Best Determined Modes

  • Without Friedmann Equation Best Evidence for Flatness is Lost (i.e., CMB Anisotropy)Might be able to determine spatial curvature independently:

    dV = r2drd / [1 - kr2]1/2r(z) = coordinate distance to object with redshift z|k|-1/2 = curvature radius

    Determine r and dr (e.g., SNe) and dV (e.g. number counts), infer k

  • My List of Burning IssuesCosmic Acceleration/Dark Energy: Most Profound Mystery in all of ScienceDark Matter: 3 pronged approach space, accelerators, and underground expts the prize is within sight!Testing the predictions of inflation inflation is knocking at the door to become part of standard cosmologyUsing the consistency and crosschecks now afforded by precision cosmological data (BBN, SDSS/2dF, WMAP, SNe) to test General Relativity in new regimes