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Status of Cosmology

Status of Cosmology. Talk presented at the Topics in Astroparticle and Underground Physics (TAUP 2001) Conference Wendy L. Freedman Carnegie Observatories. STATUS OF COSMOLOGY. Cosmological Parameters. H 0 W 0 W 0 = W m + W L + W k W m W L

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Status of Cosmology

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  1. Status of Cosmology Talk presented at the Topics in Astroparticle and Underground Physics (TAUP 2001) Conference Wendy L. Freedman Carnegie Observatories

  2. STATUS OF COSMOLOGY Cosmological Parameters H0 W0 W0 = Wm + WL + Wk Wm WL t0Age = f(H0,Wm,WL) EBL

  3. Assumptions • Homogeneity and isotropy • General relativity • Hot big bang

  4. Hubble (1929) Local Group: ~ 1 Mpc Supernovae: ~400 Mpc Virgo cluster: ~15 Mpc Hubble radius:~3000h-1 Mpc 1 pc = 3.26 light years

  5. Hubble H0 Key Project (2001) Freedman et al. (2001), Ap.J. Hubble (1929) 1st tick mark

  6. Homogeneity and Isotropy Las Campanas Redshift Survey CfA Redshift Survey Local

  7. Homogeneity and Isotropy Anglo Australian Redshift Survey March, 2001 COBE map

  8. Power Spectrum Guzzo (2001) G~ Wmh ~ 0.25 0.05 Wm h 1.00 0.25 0.35 0.70 Lineweaver, 1998

  9. CMB Anisotropies H0=70 • Robust measure of W0 • Large degeneracies • Hu, Sugiyama & Silk (1995), • Lineweaver (2001)

  10. W0 CMB Anisotropies: Netterfield et al. (2001) W0 = 1.03 0.06

  11. Wm Wm~ 0.3 Galaxy kinematics Cluster baryons Current evidence: • fb ~ 10-20% • Wb h2 = 0.02 • Wm ~ 0.3-0.4 Lensing X-ray gas

  12. WL Limits: e.g. Carroll, Press & Turner 1992 • Negative WL: For Wm<1,t0 > 10 Gyr, H0>40 WL> -7, L > -2 x 10-29 g/cm-3 • Positive WL: • For Wm<1, H0 < 100, high-z objects • WL<2, • RECALL: (Planck scale) L < 4 x 10-29 g/cm-3 rvac ~ 1092 g/cm-3 • “only” ~1060 discrepancy (electroweak)

  13. WL • Riess et al. 1998 • Perlmutter et al. 1998 Type Ia supernovae + CMB constraints Wm = 0.3, WL=0.7

  14. WL Timing Coincidence Carroll Lambda plot Evolution of density parameters in the universe WL Wi • Current epoch special • Very brief interval • where Wm and • WL comparable. Current values: Wm = 0.3, WL=0.7, Wr = 5 x 10-5 Carroll (2001)

  15. WL • Infrared observations of supernovae: • Advantages: - dust Hamuy, Krisciunas, Phillips, Freedman, et al. - chemical composition Hamuy et al. (2001) • UBVRIJHK observations • H0 • WL

  16. Direct Measure of the Expansion Rate Loeb (1998) : Lyman alpha clouds • ~2 m/s/CENTURY! • not yet feasible • Freedman (2001)

  17. Evolution of the Fine Structure Constant • Webb et al. astro-ph/ 0012539

  18. t0 : The Age of the Universe • white dwarf cooling • nucleocosmochronology • globular cluster evolution

  19. t0 U/Th • First measurement of stellar uranium Cayrel (2001) t0 = 12.6 3 Gyr Biggest uncertainty: production ratios

  20. t0 • Globular clusters Chaboyer (2001) t0=13.5 2 Gyr Biggest uncertainty: DISTANCE SCALE

  21. H0 • Distance Scale • Gravitational lens time delays • Sunyaev-Zel’dovich effect

  22. H0 Key Project • Discovery of Cepheids using HST • Intercompare several distance methods • Tests for systematic errors • Goal: H0 to 10% Freedman et al. 1994

  23. Progress in Distance Scale , HST M33 M31 B V R I m = 5 log d (pc) - 5

  24. M100 M100 – HST WFPC2 image Virgo cluster galaxy

  25. SN 1994D Cepheids Supernovae, Tully-Fisher, etc.

  26. Key Project Results Freedman et al. (2001), ApJ astro-ph/0012376

  27. Key Project Results (2) Freedman et al. (2001) H0 = 72 3 (stat.) 7 (sys.) km/sec/Mpc Largest uncertainties: Local distance scale, HST calibration

  28. Expansion Ages o

  29. Gravitational Lensing Dt = (1+zd) DdDdsa2 2 Dsc Refsdal 1964, 1966 • ~6 time delays measured • H0 ~ 60 – 70 km/sec/Mpc • systematics ~20-30% level • dark matter distribution • unknown => model • dependence/degeneracy • with H0

  30. Sunyaev-Zel’dovich Effect • 33 clusters • H0 = 63 3 (statistical) 30% (systematic) • Carlstrom et al. (2001) Birkinshaw (1999)

  31. Extragalactic Background Light • Olber’s paradox • Star formation history of universe • Baryonic mass processed in stars • Metal production in the universe IEBL NOTE: optical + IR background light = ~10% of that in CMB ~100 nW/m2/sr l (mm)

  32. Star Formation Rate Galaxy Number Counts Star Formation History of Universe • Slope of luminosity function < 0.4 (converges) • (1+z)4 surface brightness dimming severe problem Steidel et al. (1998)

  33. Redshifting M51 and M101 Kuchinski, Freedman, Madore & Trewhella (2001) • At progressively • higher z, start • to lose even the • brightest galaxies • Distant surveys • very incomplete z~1 z~2 1500A z~3 z~4

  34. Difficulty of Measuring the EBL • The optical EBL is faint! • Terrestrial airglow and zodiacal light dominate. HST Bernstein, Freedman & Madore (2001)

  35. EBL (0.1 to 1000 mm) Total EBL COBE: DIRBE FIRAS HST IRAS U V I • Total EBL 0.1 to 1000 mm: 100 35nWm-2sr-1 • ~30% of light • from stellar • nucleosynthesis • reradiated by • dust Bernstein, Freedman & Madore (2001)

  36. EBL Results • The integrated background light is ~2x greater than accounted for by galaxies detected individually. • The spectral distribution of the background light is similar to that of ordinary galaxies. • No new exotic population of objects is required (~60% undetected galaxies, ~30% missing light from detected galaxies). • The mass associated with starlight contributes ~1% of the critical density. • The metal production and star formation rate in the universe has been underestimated by a factor of ~2.

  37. Summary of Cosmological Parameters

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