Presentation on theme: "WMAP Latest Results from WMAP: Three-year Observations Eiichiro Komatsu University of Texas at Austin January 24, 2007."— Presentation transcript:
WMAP Latest Results from WMAP: Three-year Observations Eiichiro Komatsu University of Texas at Austin January 24, 2007
WMAP Three Year Science Team NASA/GSFC Chuck Bennett [PI] (-> JHU) Mike Greason Bob Hill Gary Hinshaw [CoI] Al Kogut Michele Limon Nils Odegard Janet Weiland Ed Wollack Princeton Chris Barnes (->MS) Rachel Bean (->Cornell) Olivier Dore (-> CITA) Norm Jarosik [CoI] Eiichiro Komatsu (->Texas) Mike Nolta (-> CITA) Lyman Page [CoI] Hiranya Peiris (-> Chicago) David Spergel [CoI] Licia Verde (-> U. Penn) Chicago Steve Meyer [CoI] UCLA Ned Wright [CoI] Brown Greg Tucker UBC Mark Halpern
P. Roll and D. Wilkinson, 1966 D.Wilkinson The Father of CMB Experiment
David Wilkinson (1935~2002) Science Team Meeting, July, 2002 Plotted the second point (3.2cm) on the CMB spectrum –The first confirmation of a black-body spectrum (1966) Made COBE and MAP happen and be successful The Father of CMB Experiment MAP has become WMAP in 2003
COBE/DMR, 1992 Isotropic? CMB is anisotropic! (at the 1/100,000 level)
COBE to WMAP COBE WMAP COBE 1989 WMAP 2001 [COBEs] measurements also marked the inception of cosmology as a precise science. It was not long before it was followed up, for instance by the WMAP satellite, which yielded even clearer images of the background radiation. Press Release from the Nobel Foundation
CMB: The Most Distant Light CMB was emitted when the Universe was only 380,000 years old. WMAP has measured the distance to this epoch. From (time)=(distance)/c we obtained 13.73 0.16 billion years.
The Wilkinson Microwave Anisotropy Probe A microwave satellite working at L2 Five frequency bands –K (22GHz), Ka (33GHz), Q (41GHz), V (61GHz), W (94GHz) –Multi-frequency is crucial for cleaning the Galactic emission The Key Feature: Differential Measurement –The technique inherited from COBE –10 Differencing Assemblies (DAs) –K1, Ka1, Q1, Q2, V1, V2, W1, W2, W3, & W4, each consisting of two radiometers that are sensitive to orthogonal linear polarization modes. Temperature anisotropy is measured by single difference. Polarization anisotropy is measured by double difference. POLARIZATION DATA!!
Microwave Sky (minus the mean temperature) as seen by WMAP
What Temperature Tells Us Distance to z~1100 Baryon- to-Photon Ratio Matter-Radiation Equality Epoch Dark Energy/ New Physics?
R. Sachs and A. Wolfe, 1967 SOLVE GENERAL RELATIVISTIC BOLTZMANN EQUATIONS TO THE FIRST ORDER IN PERTURBATIONSSOLVE GENERAL RELATIVISTIC BOLTZMANN EQUATIONS TO THE FIRST ORDER IN PERTURBATIONS
Boltzmann Equation Temperature anisotropy,, can be generated by gravitational effect (noted as SW = Sachs-Wolfe) Linear polarization (Q & U) cannot be generated gravitationally. It is generated only by scattering (noted as C = Compton scattering). Circular polarization (V) would not be generated.
For metric perturbations in the form of: the Sachs-Wolfe terms are given by where is the directional cosine of photon propagations. Newtonian potential Curvature perturbations 1.The 1st term = gravitational redshift 2.The 2nd term = integrated Sachs-Wolfe effect h 00 /2 h ij /2 (higher T)
CMB to Cosmology &Third Baryon/Photon Density Ratio Low Multipoles (ISW) Constraints on Inflation Models
n s : Tilting Spectrum n s >1: Blue Spectrum n s >1: Blue Spectrum
n s : Tilting Spectrum n s <1: Red Spectrum n s <1: Red Spectrum
Composition of Our Universe Determined by WMAP 3yr 76% 20% 4% Mysterious Dark Energy occupies 75.9 3.4% of the total energy of the Universe.
Parameter Determination (ML): First Year vs Three Years The simplest LCDM model fits the data very well. –A power-law primordial power spectrum –Three relativistic neutrino species –Flat universe with cosmological constant The maximum likelihood values very consistent –Matter density and sigma8 went down slightly (w/SZ)(w/o SZ) 2.22 0.127 73.2 0.091 0.954 0.236 0.756
Parameter Determination (Mean): First Year vs Three Years ML and Mean agree better for the 3yr data. –Degeneracy broken! (w/SZ)(w/o SZ) 2.229 0.128 73.2 0.089 0.958 0.241 0.761
Degeneracy Broken: Negative Tilt Parameter Degeneracy Line from Temperature Data Alone Polarization Data Nailed Tau
No Detection of Gravity Waves (yet) Our ability to constrain the amplitude of gravity waves is still coming mostly from the temperature spectrum. –r<0.55 (95%) The B-mode spectrum adds very little. WMAP would have to integrate for >15 years to detect the B- mode spectrum from inflation. r = Gravity Wave Amplitude / Scalar Curvature Fluctuations
What Should WMAP Say About Inflation? (See W.Kinneys Talk) Hint for ns<1 Zero GW (r=0) The 1-d marginalized constraint from WMAP alone is n s =0.96+-0.02. Non-zero GW The 2-d joint constraint still allows for ns=1.
What Should WMAP Say About Flatness of the Universe? Flatness, or very low Hubble s constant? If H=30km/s/Mpc, a closed universe with Omega=1.3 w/o cosmological constant still fits the WMAP data.
What Should WMAP Say About Dark Energy? Not much! The CMB data alone cannot constrain w very well. Combining the large-scale structure data or supernova data breaks degeneracy between w and matter density.
Understanding of –Noise, –Systematics, –Foreground, and Analysis techniques have significantly improved from the first-year release. A simple LCDM model fits both the temperature and polarization data very well. To-do list for the next data release (now working on the 5-year data) Understand FG and noise better. We are still using only 1/2 of the polarization data. These improvements, combined with more years of data, would further reduce the error on tau. Full 3-yr would give delta(tau)~0.02 Full 6-yr would give delta(tau)~0.014 (hopefully) This will give us a better estimate of the tilt, and better constraints on inflation. Summary Tau=0.09+-0.03