Ringing in the New Cosmology

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Blaise Paul
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1 Ringing in the New Cosmology 80 T (µk) Boom98 CBI Maxima-1 DASI l (multipole) Acoustic Peaks in the CMB Wayne Hu

2 Temperature Maps

3 CMB Isotropy Actual Temperature Data COBE 1992

4 Dipole Anisotropy our motion 1 part in 1000 COBE 1992

Large Angle Anisotropies 1 part in 100000

5 Large Angle Anisotropies 1 part in size matters: smallness linear physics COBE 1992

6 Understanding Maps COBE's fuzzy vision W. Hu

7 Understanding Maps COBE's fuzzy vision W. Hu

8 Understanding Maps COBE's imperfect reception W. Hu

9 Understanding Maps Our best guess for the original map W. Hu

10 Precision Cosmology COBE Maxima Hanany, et al. (2000) BOOMERanG de Bernardis, et al. (2000)

11 New DASI Data µK 100µK

12 What MAP Should See Simulated Data

13 Original Power Spectra of Maps 64º Band Filtered

14 Ringing in the New Cosmology

15 Physical Landscape

16 Thermal History

17 A Brief Thermal History Universe cools as it expands, T 1/a = (1+z)

18 A Brief Thermal History CMB photons hotter at high redhift z At z~1000, T~3000K: photons ionize hydrogen

19 A Brief Thermal History Rapid scattering couples photons and baryons Plasma behaves as perfect fluid

20 A Brief Thermal History Redshift-ionization Photon-baryon fluid with pressure

21 Acoustic Oscillations

22 Gravitational Ringing Potential wells = inflationary seeds of structure Fluid falls into wells, pressure resists: acoustic oscillations

23 Plane Waves Potential wells: part of a fluctuation spectrum Plane wave decomposition

24 Harmonic Modes Frequency proportional to wavenumber: ω=kc s Twice the wavenumber = twice the frequency of oscillation

25 Seeing Sound Oscillations frozen at recombination Compression=hot spots, Rarefaction=cold spots

26 Extrema=Peaks First peak = mode that just compresses Recombination T/T Ψ /3 Θ+Ψ k 1 =π/ sound horizon First Peak time N.B.: "compression" short for compression inside potential wells and rarefaction inside potential hills

27 Extrema=Peaks First peak = mode that just compresses Second peak = mode that compresses then rarefies: twice the wavenumber Recombination Recombination T/T Θ+Ψ First Peak T/T Θ+Ψ time time Ψ /3 k 1 =π/ sound horizon Ψ /3 k 2 =2k 1 Second Peak

28 Extrema=Peaks First peak = mode that just compresses Second peak = mode that compresses then rarefies: twice the wavenumber Harmonic peaks: 1:2:3 in wavenumber Recombination Recombination T/T Θ+Ψ First Peak T/T Θ+Ψ time time Ψ /3 k 1 =π/ sound horizon Ψ /3 k 2 =2k 1 Second Peak

29 Angular Peaks

30 Why Anisotropies? Spatial temperature perturbation oscillating in time and frozen in at recombination Providence Oscillations Spatial Inhom.

31 Peaks in Angular Power Standing wave acoustic oscillations in local temperature

32 Peaks in Angular Power Oscillations frozen in at recombination Prompt release of photons

33 Peaks in Angular Power Photons ariving at observer show an anisotropy whose angular scale decreases with time Temperature inhomogeneity anisotropy

34 Peaks in Angular Power The Anisotropy Formation Process

35 Acoustic Landscape

36 The First Peak

37 First Peak Precisely Measured

38 Spatial Curvature Physical scale of peak = distance sound travels Angular scale measured: comoving angular diameter distance test for curvature Flat Closed

39 Curvature in the Power Spectrum Features scale with angular diameter distance Angular location of the first peak

40 A (Nearly?) Flat Universe h<0.8 Ω b h 2 <0.025 ΩΛ BOOMERanG MAXIMA closed open Ω m Hubble constant! (Ω m h 2 : higher peaks) How Flat? Age of the universe

41 What Makes It Flat? h<0.8 Ω b h 2 <0.025 ΩΛ BOOMERanG Clusters MAXIMA closed open Ω m Info on H 0, Ω m, or Ω Λ breaks degeneracy H 0 : currently by assuming flatness, future by measuring Ω m h 2 Cosmic Complementarity

42 A (Nearly?!) Flat Universe ΩΛ h<0.8 Ω b h 2 <0.025 MAXIMA Perlmutter et al. (1998) Riess et al. (1998) BOOMERanG closed open SNe Clusters Ω m Currently showing consistency with Ω Λ >0

43 Dirty Laundry: Standard Rulers Calibrating the Standard Rulers Sound Horizon Damping Scale Baryons Matter/Radiation Baryons Matter/Radiation

44 The Second Peak

45 Baryon & Inertia Baryons add inertia to the fluid Equivalent to adding mass on a spring Same initial conditions Same null in fluctuations Unequal amplitudes of extrema

46 A Baryon-meter Low baryons: symmetric compressions and rarefactions T time Low Baryons

47 A Baryon-meter Load the fluid adding to gravitational force Enhance compressional peaks (odd) over rarefaction peaks (even) T time Baryon Loading

48 A Baryon-meter Enhance compressional peaks (odd) over rarefaction peaks (even) e.g. relative suppression of second peak T time

49 Baryons in the Power Spectrum

50 Second Peak Detected

51 Score Card

52 Third Peak

53 Radiation and Dark Matter Radiation domination: potential wells created by CMB itself Pressure support potential decay Elimation of modulation from baryon loading

54 Dark Matter in the Power Spectrum

55 Third Peak Constrained

56 Driving Effects and Matter/Radiation Potential perturbation: Radiation Potential: k 2 Ψ = 4πGa 2 δρ generated by radiation inside sound horizon δρ/ρ pressure supported δρ hence Ψ decays with expansion Ψ T/T η Θ+Ψ Hu & Sugiyama (1995)

57 Driving Effects and Matter/Radiation Potential perturbation: Radiation Potential: Potential Radiation: Feedback stops at matter domination k 2 Ψ = 4πGa 2 δρ generated by radiation inside sound horizon δρ/ρ pressure supported δρ hence Ψ decays with expansion Ψ decay timed to drive oscillation 2Ψ + (1/3)Ψ = (5/3)Ψ 5x boost Ψ T/T Θ+Ψ η Hu & Sugiyama (1995)

58 Driving Effects and Matter/Radiation Potential perturbation: Radiation Potential: Potential Radiation: Feedback stops at matter domination k 2 Ψ = 4πGa 2 δρ generated by radiation inside sound horizon δρ/ρ pressure supported δρ hence Ψ decays with expansion Ψ decay timed to drive oscillation 2Ψ + (1/3)Ψ = (5/3)Ψ 5x boost Ψ T/T Θ+Ψ η Hu & Sugiyama (1995)

59 Damping Tail

60 Diffusion Damping Random walk during recombination Dissipation as hot meets cold Physical scale for standard ruler or calibration

61 Dissipation / Diffusion Damping Imperfections in the coupled fluid mean free path λ C in the baryons Random walk over diffusion scale: geometric mean of mfp & horizon λ D ~ λ C N ~ λ C η >> λ C Overtake wavelength: λ D ~ λ ; second order in λ C /λ Viscous damping for R<1; heat conduction damping for R>1 N=η / λ C 1.0 λ D ~ λ C N λ Power 0.1 perfect fluid instant decoupling Silk (1968); Hu & Sugiyama (1995); Hu & White (1996) l

62 Dissipation / Diffusion Damping Rapid increase at recombination as mfp Independent of (robust to changes in) perturbation spectrum Robust physical scale for angular diameter distance test (Ω K, Ω Λ ) Recombination 1.0 Power 0.1 perfect fluid instant decoupling recombination Silk (1968); Hu & Sugiyama (1995); Hu & White (1996) l

63 The Peaks

64 Mapping Dark Matter with the Damping Tail Hu (2001)

65 Mapping Dark Matter with the Damping Tail New gradient-divergence statistic: original mass (deflection) map reconstructed 1.5' beam; 30µK-arcmin noise Hu (2001)

66 Mapping Dark Matter with the Damping Tail Resolving the damping tail crucial to mapping Lower resolution expmt measure power spectrum deflection power (x 10 7 ) Planck l

67 Beyond the Peaks

68 Degeneracies Multiple cosmological parameters have (nearly) degenerate effects on the power spectrum Example: reionization and gravity waves

69 Polarization Thomson of quadrupole temperature anisotropy Linear polarization:

70 Polarization Generation Quadrupole anisotropies generated in optically thin regime Anisotropies <10% polarized

71 Why Polarization is Difficult Source of polarization is the scattering of quadrupole anisotropies Rapid scattering destroys quadrupole anisotropies Polarization only from the optically thin period before full transparency T (µk) < 10% l

72 Polarization Patterns Pattern reflects the projection of quadrupole anisotropies Three types: density, vorticity, gravity waves Potential to isolate gravity waves hot m=0 m=1 m=2 v cold hot v v Density Vorticity Gravity Waves

73 Local vs. Observable Polarization Thomson scattering generates a pure E-pattern locally Plane wave perturbation modulates the amplitude If modulation: in a 0º or 90º direction then E in a 45º direction as polarization then B Last Scat. Surface hot cold θ observer Plane Wave Modulation Hu & White (1997)

74 Secondary Anisotropies CMB photons traverse the large-scale structure of the universe Scattering (~few%), gravitational redshift, lensing

75 Power in Secondaries Gravitational ISW (redshift) Effect Weak Lensing Scattering Doppler Effect Vishniac Effect Kinetic SZ Effect Patchy Reionization Thermal SZ Effect Separation Arcminute Scales Spectrum Non-Gaussianity Polarization Power primary ISW doppler linear l nonlin SZ lensing linear nonlin patch Vishniac

76 Summary Precision cosmology has arrived Sound physics seen (pun intended) Consistent with inflationary initial conditions

77 Summary Precision cosmology has arrived Sound physics seen (pun intended) Consistent with inflationary initial conditions First peak nailed: nearly flat universe Second detected: baryonic dark matter (consistent with Big Bang Nucleosynthesis) Third constrained: cold dark matter required

78 Summary Precision cosmology has arrived Sound physics seen (pun intended) Consistent with inflationary initial conditions First peak nailed: nearly flat universe Second detected: baryonic dark matter (consistent with Big Bang Nucleosynthesis) Third constrained: cold dark matter required Degeneracies remain dark energy: complementary measures gravitational waves: polarization reionization: polarization & secondaries

79 Maps Power Spectrum Thermal History Ringing Plane Waves Harmonics Extrema Seing Sound Peaks First Peak Data Index Geometry C l 's: curvature Flatness Second Peak Baryon Inertia Baryonmeter C l 's: baryons Radiation C l 's: dark matter Damping Diffusion C l 's: rulers Degeneracies Polarization Generation Patterns Secondaries C l 's: secondaries Summary Details & Outtakes Microsoft

CMB Anisotropies: The Acoustic Peaks. Boom98 CBI Maxima-1 DASI. l (multipole) Astro 280, Spring 2002 Wayne Hu

CMB Anisotropies: The Acoustic Peaks 80 T (µk) 60 40 20 Boom98 CBI Maxima-1 DASI 500 1000 1500 l (multipole) Astro 280, Spring 2002 Wayne Hu Physical Landscape 100 IAB Sask 80 Viper BAM TOCO Sound Waves