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The Universe is expanding

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  1. The Universe is expanding • The Universe is filled with radiation • The Early Universe was Hot & Dense • The Early Universe was a Cosmic Nuclear Reactor!

  2. Neutron Abundance vs. Time / Temperature p + en + e … Rates set byn “Freeze – Out” ? Wrong! (n/p)eq BBN “Begins”  Decay

  3. History of nmeasurements Statistical Errors versus SystematicErrors! 885.7  0.8 sec

  4. BBN “Begins” at T  70 keV when n / p  1 / 7 Coulomb Barriers and absence of free neutrons terminate BBN at T  30 keV tBBN  4  24 min.

  5. Pre - BBN Post - BBN Only n & p Mainly H & 4He

  6. Baryon Density Parameter : B Note : Baryons  Nucleons B  nN /n ; 10   B= 274 Bh2 Hubble Parameter : H = H(z) In The Early Universe: H2 α Gρ

  7. “Standard” Big Bang Nucleosynthesis (SBBN) An Expanding Universe Described By General Relativity, Filled With Radiation, Including 3 Flavors Of Light Neutrinos (N = 3) The relic abundances of D, 3He, 4He, 7Li are predicted as a function of only one parameter : * The baryon to photon ratio : B

  8. Evolution of mass - 2 10 More nucleons  less D

  9. Two pathways to mass - 3 More nucleons  less mass - 3

  10. Two pathways to mass - 7

  11. BBN abundances of masses – 6, 9 –11 Abundances Are Very Small !

  12. Y is very weakly dependent on the nucleon abundance All/most neutrons are incorporated in 4He n/p  1/7  Y  2n /(n + p) 0.25 Y4He Mass Fraction Y 4y/(1 + 4y) y  n(He)/n(H) YP DOES depend on the competition between Γwk & H

  13. SBBN – Predicted Primordial Abundances 4He Mass Fraction Mostly H &4He BBN Abundances ofD, 3He, 7Li are RATE (DENSITY) LIMITED 7Li 7Be D, 3He, 7Li are potential BARYOMETERS

  14. Use BBN (D/H) P vs. 10to constrain B Predict (D/H)P “Measure” (D/H) P Infer B (B) at ~ 20 Min.

  15. 4He (mass fraction Y) is NOT Rate Limited • 4He IS n/p Limited Y is sensitive to the EXPANSION RATE ( H 1/2 ) • Expansion Rate Parameter : S  H´/H • S  H´/H  (´/)1/2  (1 + 7N /43)1/2 • where ´   + N andN  3 + N

  16. The Expansion Rate Parameter (S) Is A Probe Of Non-Standard Physics • S2  (H/ H)2= G/G  1 + 7N /43 • * S may be parameterized by N N (-) /  and N  3 + N NOTE : G/ G = S2 1 + 7N / 43 • 4He is sensitive to S (N) ; D probes B

  17. Big Bang Nucleosynthesis (BBN) An Expanding Universe Described By General Relativity, Filled With Radiation, Including N Flavors Of Light Neutrinos The relic abundances of D, 3He, 4He, 7Li are predicted as a function of two parameters : * The baryon to photon ratio : B (SBBN) * The effective number of neutrinos : N

  18. 4Heis an early – Universe Chronometer Y vs. D/H N =2, 3, 4 (S = 0.91, 1.00, 1.08) Y0.013N 0.16 (S – 1)

  19. Isoabundance Contours for 105(D/H)P & YP YP & yDP  105 (D/H)P 4.0 2.0 3.0 0.25 0.24 0.23 D&4HeIsoabundance Contours Kneller & Steigman (2004)

  20. Kneller & Steigman (2004) & Steigman (2007) yDP 105(D/H)P = 46.5 (1 ± 0.03) D-1.6 YP = (0.2386 ±0.0006) + He / 625 y7  1010(7Li/H) = (1.0 ± 0.1) (LI)2 / 8.5 where : D 10 – 6 (S – 1) He  10 – 100 (S – 1) Li  10 – 3 (S – 1)

  21. Post – BBN Evolution • As gas cycles through stars,D is only DESTROYED • As gas cycles through stars,3He is DESTROYED , • PRODUCED and, some 3He SURVIVES • Stars burn H to 4He (and produce heavy elements) •  4He INCREASES (along with CNO) • Cosmic Rays and SOME Stars PRODUCE 7Li BUT, • 7Li is DESTROYED in most stars

  22. Observing D in QSOALS Ly -  Absorption

  23. D/H vs. number of H atoms per cm2 Observations of Deuterium In 7 High-Redshift, Low-Metallicity QSO Absorption Line Systems 105(D/H)P = 2.7 ± 0.2 (Weighted Mean of D/H) (Weighted mean of log (D/H) 105(D/H)P = 2.8 ± 0.2)

  24. log (D/H) vs. Oxygen Abundance log(105(D/H)P) = 0.45 ± 0.03

  25. (D/H)obs + BBNpred10 =6.0± 0.3 BBN V. Simha & G. S.

  26. CMB ΔT Δ ΔTrms vs. Δ: Temperature Anisotropy Spectrum

  27. CMB Temperature Anisotropy Spectrum (T2 vs. ) Depends On The Baryon Density  10=4.5,6.1,7.5 V. Simha & G. S. The CMB provides an early - Universe Baryometer

  28. CMB + LSS10 =6.1±0.2 10Likelihood CMB V. Simha & G. S.

  29. D/H vs. number of H atoms per cm2 Observations of Deuterium In 7 High-Redshift, Low-Metallicity QSO Absorption Line Systems BBN + CMB/LSS  105(D/H)P = 2.6 ± 0.1

  30. BBN (~ 20 min) & CMB (~ 380 kyr) AGREE 10Likelihoods CMB BBN V. Simha & G. S.

  31. 3He Observed In Galactic HII Regions No clear correlation with O/H Stellar Produced ? SBBN

  32. Oxygen Gradient In The Galaxy More gas cycled through stars Less gas cycled through stars

  33. 3He Observed In Galactic HII Regions No clear correlation with R Stellar Produced ? SBBN

  34. The 4He abundance is measured via H and He recombination lines from metal-poor, extragalactic H regions (Blue, Compact Galaxies). Theorist’s H Region Real H Region

  35. In determining the primordial helium abundance, systematic errors (underlying stellar absorption, temperature variations, ionization corrections, atomic emissivities, inhomogeneities, ….) dominate over the statistical errors and the uncertain extrapolation to zero metallicity.  σ(YP)≈ 0.006, NOT < 0.001 ! Note : ΔY = (ΔY/ΔZ) Z <<σ(YP)

  36. 4He (YP) Observed In Extragalactic H  Regions As O/H  0, Y  0 SBBN Prediction: YP≈ 0.249 K. Olive

  37. SBBN 10Likelihoods from D and 4He AGREE ? to be continued …

  38. Lithium – 7 Is A Problem [Li] ≡ 12 + log(Li/H) [Li]SBBN 2.6 – 2.7 [Li]OBS 2.1 Li too low !

  39. More Recent Lithium – 7 Data [Li] ≡ 12 + log(Li/H) [Li]SBBN 2.70 ± 0.07 NGC 6397 Asplund et al. 2006 Boesgaard et al. 2005 Aoki et al. 2009 Lind et al. 2009 Where is the Spite Plateau ?

  40. YP vs. (D/H)P for N = 2, 3, 4 N  3 ? But, new (2010) analyses now claim YP = 0.256 ± 0.006 !

  41. A Non-Standard BBN Example (Neff < 3) Late Decay of a Massive Particle Kawasaki,Kohri&Sugiyama & Low Reheat Temp. (TR  MeV) Neff<3  Relic Neutrinos Not Fully (Re)Populated

  42. Isoabundance Contours for 105(D/H)P & YP YP & yD  105 (D/H) 4.0 3.0 2.0 0.25 0.24 0.23 Kneller & Steigman (2004)

  43. Nvs.10 From BBN (D & 4He) ( YP < 0.255 @ 2 σ ) BBN Constrains N N < 4 N> 1 V. Simha & G. S.

  44. CMB Temperature Anisotropy Spectrum Depends on the Radiation Density R(SorN)   N =1, 3,5 V. Simha & G. S. The CMB / LSS is an early - Universe Chronometer

  45. N Is Degenerate With mh2 The degeneracy can be broken - partially - by H0 (HST) and LSS 1 + zeq =m / R 1 + zeq≈ 3200 V. Simha & G. S.

  46. CMB + LSS + HST Prior on H0 Nvs.10 CMB + LSS Constrain 10 V. Simha & G. S.

  47. BBN (D & 4He) & CMB + LSS + HST AGREE ! N vs. 10 CMB + LSS BBN V. Simha & G. S.

  48. But, even for N  3 Y + DH LiH 4.0  0.7 x 1010 yLi  1010 (Li/H) 4.0 3.0 2.0 0.25 4.0 0.24 0.23 Li depleted/diluted in Pop  stars ? Kneller & Steigman (2004)