WMAP – 3-year results Fabio Finelli INAF/OAB & INAF/IASF-BO Lauro Moscardini Dip. Astronomia UniBo Bologna, 27 Aprile 2006 SOURCES 1. WMAP 1st year papers 2. WMAP 3rd papers 3. A. Lewis, astro-ph/0603753 4. Planck Bluebook, astro-ph/0604069 5. Wayne Hu’s webpage: http://background.uchicago.edu/whu Bologna, 27 Aprile 2006 WMAP • WMAP: spinning (~0.5 rpm), precessing satellite orbiting L2 • dual Gregorian (1.4×1.6m) mirror system • passively cooled to <95K • radiometers measuring phase and amplitude of incoming waves • Proposed in 1995; selected in 1996; launched in june 2001; possibly 8-years mission • 13 papers in 2003, 7311 citations up today • 4 new papers in march 2006, 160 citations up today Bologna, 27 Aprile 2006 Channels • frequencies: 22, 30, 40, 60, 90 GHz (3.3 to 13.6 mm wavelength) • resolution: 0.230.93 degrees • sensitivity: ~35µK per 0.3×0.3 degree pixel Bologna, 27 Aprile 2006 Channels • frequencies: 22, 30, 40, 60, 90 GHz (3.3 to 13.6 mm wavelength) • resolution: 0.230.93 degrees • sensitivity: ~35µK per 0.3×0.3 degree pixel Bologna, 27 Aprile 2006 Sky Maps foregrounds: synchrotron, dust, free-free emission Bologna, 27 Aprile 2006 Temperature Map • foreground subtraction: spectra differ from the CMB's Planck spectrum • comparison of signals from different channels • fitting of foreground templates Bologna, 27 Aprile 2006 Power-Spectrum Analysis • subtraction of mean temperature; relative temperature fluctuations • expansion into spherical harmonics; coefficients alm • power spectrum Cl=<|alm|2> , related to the matter power spectrum P(k) • principal effects: – Sachs-Wolfe effect – acoustic oscillations – Silk damping Bologna, 27 Aprile 2006 Courtesy by W. Hu Bologna, 27 Aprile 2006 Bologna, 27 Aprile 2006 Mechanisms for anisotropies gravity: gravitational red- or blue-shift density: adiabatic process compression increases T, while expansion decreases T velocity: Doppler effect Different contributions must be summed up Primary anisotropies: produced on the last scattering surface Secondary anisotropies: produced along the trajectory to the observer Bologna, 27 Aprile 2006 On scales larger than the horizon (i.e. large angles, small l) Velocity can be neglected (dipole), microphysics too, gravity wins against density! Temperature fluctuations are directly proportional to the gravitational potential: Sachs-Wolfe effect Notice: overdensity are colder than average! Already observed by COBE in 1991! Good estimates for amplitude and slope of P(k), but problems of cosmic variance Bologna, 27 Aprile 2006 Bologna, 27 Aprile 2006 Bologna, 27 Aprile 2006 Bologna, 27 Aprile 2006 Bologna, 27 Aprile 2006 Bologna, 27 Aprile 2006 Bologna, 27 Aprile 2006 The cosmological parameters (I): the density parameters i • Matter: m • Dark energy: DE (w P/ c2=-1 is the cosmological constant ; w -1 is the quintessence) • Baryons: b • Curvature: K=1 - i • Total: 0 =1- K Bologna, 27 Aprile 2006 The cosmological parameters (II): the spectral parameters Standard inflationary models predict that primordial fluctuations are • Gaussian • Adiabatic • Scale invariant, i.e. with logarithmic slope of the power spectrum n=1: P(k)=A kn The amplitude A is usually expressed in terms of the variance computed on a scale of 8 Mpc/h: 8 Bologna, 27 Aprile 2006 The cosmological parameters (III): the other ones • The Hubble constant H0 and its redshift evolution: measures the expansion rate of the universe and enters the distance definitions • The optical depth : it is related to the probability that a CMB photon with an electron along the trajectory: dP=ne T c dt=-d If there is re-ionization at a given redshift zre, photons are diffuse there is a suppression of fluctuations on scales smaller than the horizon scale at zre (warning: degeneracy with spectral index n). The higher is zre, the smaller is the angular scale involved by diffusion. Bologna, 27 Aprile 2006 Bologna, 27 Aprile 2006 Power Spectra and Cosmological Parameters Varying the baryonic density Bologna, 27 Aprile 2006 Power Spectra and Cosmological Parameters Varying the Hubble constant Bologna, 27 Aprile 2006 Power Spectra and Cosmological Parameters Varying the matter density Bologna, 27 Aprile 2006 Power Spectra and Cosmological Parameters Varying the total density Bologna, 27 Aprile 2006 CMB Polarisation • CMB photons have last been Thomson scattered • directional dependence of Thomson cross section imprints polarisation • polarisation pattern has similar, but shifted power spectrum Bologna, 27 Aprile 2006 Polarisation and Reionisation • Universe recombined when CMB formed • hydrogen was later reionised • ionised hydrogen damps primordial fluctuations • creates secondary polarisation • constraints on reionisation from temperaturepolarisation and polarisation power spectra Bologna, 27 Aprile 2006 Where were we? CMB anisotropies WMAP 1st year results (Feb.03): TT & TE EE detection by DASI (02), CBI (04), CAPMAP (05), Boomerang (05) Galaxy surveys 2dF: Percival et al. (02), Cole et al. (05). SDSS: Tegmark et al. (04), Seljak et al. (05). Ly used heavily in WMAP1, but not in WMAP3: “… further study is needed if the new values are consistent with Ly data.” See however Viel et al. (06), Seljak et al. (06) for WMAP3 + Ly Bologna, 27 Aprile 2006 Issues after WMAP 1st year High value for Sticky points out of the CDM fit Low amplitude for low multipoles of the Cl pattern Weird alignment of the l=2,3 of alm Evidence of running of the spectral index ? Bologna, 27 Aprile 2006 Will these “waves” in 1st year data persist? Bologna, 27 Aprile 2006 Temperature WMAP3 plus small scale CMB data The spectrum is cosmic variance limited to l=400 (354 1st year)and S/N>1 up to l=850 (658 1st year) Bologna, 27 Aprile 2006 Red: WMAP1 Black: WMAP3 Points: ratio of WMAP3 over WMAP1 value Red line: ratio of window function WMAP1 over WMAP3 Red: WMAP1 with 06 analysis and 06 windows function Black: WMAP3 Bologna, 27 Aprile 2006 WMAP1 WMAP3 Anomaly on the octupole alleviated; quadrupole remains low TE in better agreement with CDM; is almost half of 1st yr value Some (but not all) of the sticky points remain Bologna, 27 Aprile 2006 Lines: Red: WMAP1 Orange: WMAP1 + CBI +ACBAR Black: WMAP3 Points: Grey: WMAP1 Black: WMAP3 Bologna, 27 Aprile 2006 CDM plus constraints courtesy from Spergel et al., 2006 Bologna, 27 Aprile 2006 Bologna, 27 Aprile 2006 CDM plus is a good fit to WMAP courtesy from Hinshaw et al., 2006 Bologna, 27 Aprile 2006 CMB Polarization Polarization only useful for measuring tau for near future Polarization probably best way to detect tensors Bologna, 27 Aprile 2006 Cosmological Parameters: Main WMAP3 parameter results rely on polarization courtesy from A. Lewis, 2006 Bologna, 27 Aprile 2006 WMAP3 TT with tau = 0.10 ± 0.03 prior (equiv to WMAP EE) Black: TT+prior Red: full WMAP courtesy from A. Lewis, 2006 Bologna, 27 Aprile 2006 Implications for Nucleosynthesis Bologna, 27 Aprile 2006 From =0.170.04 (1st year) To =0.090.03 (3 years) courtesy from Page et al., 2006 Bologna, 27 Aprile 2006 1 e 2 contours: Light Blue: WMAP1 Red: WMAP1 + CBI +ACBAR Blue: WMAP3 courtesy from Spergel et al., 2006 Bologna, 27 Aprile 2006 Is Harrison-Zeldovich Ruled out? ns =1 So: ns < 1 or tau is high or there are tensors or the model is wrong or we are quite unlucky Bologna, 27 Aprile 2006 Dark Energy: wDE≠ w = -1 for CMB anisotropies we need DE perturbations wDE constant in time cDE =1 (pDE=c2DE DE+…). Bologna, 27 Aprile 2006 WMAP 3 years results without DE perturbations are flawed Effect known since Caldwell,Dave, Steinhardt PRL 1998 Abramo, Finelli, Pereira PRD 2004 Bologna, 27 Aprile 2006 Massive Neutrinos courtesy from Spergel et al., 2006 Bologna, 27 Aprile 2006 Curvature K≠0 courtesy from Spergel et al., 2006 Bologna, 27 Aprile 2006 Curvature K≠0 plus Dark Energy courtesy from Spergel et al., 2006 Bologna, 27 Aprile 2006 Gravity Waves Baldi,Finelli,Matarrese, PRD72 (2005) rk* = PT(k*)/PS(k*) r0.002 < 0.55 (2) r0.002 < 0.28 (2) WMAP3 only r0.002 < 1.28 (2) WMAP1 only WMAP3 plus SDSS r0.002 < 1.14 (2) WMAP1 plus 2dFGRS Bologna, 27 Aprile 2006 LCDM+ Tensors No evidence from tensor modes -is not going to get much better from TT! courtesy from A. Lewis, 2006 Single standard scalar field inflation: r = - 8 nT Leach & Liddle, PRD (2003) Finelli et al., in preparation (2006) Bologna, 27 Aprile 2006 WMAP-3 yr twist: SZ SZ Marginalization Spergel et al. Black: SZ marge; Red: no SZ Slightly LOWERS ns Bologna, 27 Aprile 2006 CMB lensing and WMAP3 Black: with red: without - increases ns not included in Spergel et al analysis opposite effect to SZ marginalization Bologna, 27 Aprile 2006 And Planck? • to be launched in 2008 • improved frequency coverage (30-857 GHz) for improved foreground subtraction • improved resolution (>5') and sensitivity (~µK) • more accurate polarisation measurement • foregrounds! Bologna, 27 Aprile 2006 Planck vs WMAP:1 courtesy from C. Burigana Bologna, 27 Aprile 2006 Planck vs WMAP:2 courtesy from C. Burigana Bologna, 27 Aprile 2006 Planck vs WMAP:3 courtesy from Planck Bluebook, astro-ph/0604069 Bologna, 27 Aprile 2006 Planck vs WMAP:4 courtesy from Spergel et al., 2006 Bologna, 27 Aprile 2006 Planck vs WMAP:5 courtesy from Planck Bluebook, astro-ph/0604069 Bologna, 27 Aprile 2006

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