FIRST RESULTS FROM THE WMAP MISSION

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FIRST RESULTS FROM THE WMAP MISSION
Wilkinson Microwave Anisotropy Probe
Chuck Bennett, WMAP P.I.
April 2, 2003 FERMILAB
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Prof. David T. Wilkinson Wilkinson Microwave
Anisotropy Probe (WMAP)
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WMAPs Purpose

• To make a detailed full-sky map of the cosmic
  microwave background (CMB) radiation to constrain
  the cosmology of our universe.

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WMAP Science Team

PRINCETON U.
GODDARD
U. CHICAGO
Stephan Meyer
Charles Bennett, P.I. Robert Hill Gary Hinshaw Al
Kogut Michele Limon Nils Odegard Janet
Weiland Edward Wollack
Chris Barnes Norman Jarosik Eiichiro
Komatsu Micheal Nolta Lyman Page Hiranya
Peiris David Spergel Licia Verde
UCLA
Edward Wright
U. BRIT COLUMBIA
Mark Halpern
BROWN U.
Greg Tucker
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WMAP Launch
June 30, 2001 at 347 EDT Delta II Model
7425-10 Delta Launch Number 286 Star-48 third
stage motor Cape Canaveral Air Force Station Pad
SLC-17B
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Trajectory to L2
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WMAPs First 100 Days
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Experimental ApproachMinimize Systematic
Measurement Errors

• Differential design to minimize systematic errors
• 5 microwave frequencies to understand foregrounds
  
• 20 radiometers to allow multiple cross checks
• Sensitivity to polarization
• Accurate calibration (lt0.5)
• ? in-flight calibration using modulation of the
  dipole
• In-flight beam measurements on Jupiter
• Minimize sidelobes diffracted signals from
  Earth, Sun, Moon
• ? L2 orbit
• Multiple modulation periods to identify
  systematic effects
• Minimize all observatory changes
• ? L2 orbit constant survey mode operations
• Thermal stability / Passive thermal control ? L2
• Rapid and complex sky scan
• ?observe 30 of the sky in an hour

SPIN-SYNCHRONOUS NON-SKY SIGNALS WERE THE LEADING
CONCERN
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Systematic Error Results

• No corrections to the first year
• WMAP data
• were required for spin-synchronous
• systematic errors

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Differential Design
lines of sight
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Scan Pattern
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State-of-the-Art Microwave Receivers
10 Differencing Assemblies 4 _at_ 94 GHz W-band 2
_at_ 61 GHz V-band 2 _at_ 41 GHz Q-band 1 _at_ 33 GHz
Ka-band 1 _at_ 23 GHz K-band
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Designed by M. Pospieszalski at NRAO
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Feed Horn Arrangement in Focal Plane

• View looking at feeds from secondary
• Side A is y direction, Side B is -y direction
• E-plane polarization shown for longitudinal OMT
  port (radiometer side 1)

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Jupiter Beam Maps
B-side
A-side
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K Band (23 GHz)
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Ka Band (33 GHz)
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Q Band (41 GHz)
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V Band (61 GHz)
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W Band (94 GHz)
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Number of Observations/Pixel
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Systematic Error Cross-Checks
(Q1Q2)/2
(Q1-Q2)/2
(V1-V2)/2
(V1V2)/2
(W12-W34)/2
(W12W34)/2
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COBE-WMAP Comparison
COBE
WMAP
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COBE-WMAP Comparison
COBE DMR 53 GHz
WMAP Q/V Combined (to approximate 53 GHz)
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COBE-WMAP Comparison
Difference
Noise
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3-Color Maps
Q band V band W band
Dipole- subtracted
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Internal Linear Combination CMB
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COBE-WMAP Comparison
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Foreground Emission
Extinction Corrected Ha (White
Line t1)
Free-free from WMAP at K band
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Synchrotron Emission
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MAP Dust Foreground
FDS Model 8 at W band (94 GHz)
Temperature (µK)
400
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15000
Dust Spectral Index
10000
Number of Pixels
5000
MAP Thermal Dust at W band (94 GHz)
0
1.5
2.0
1.8
2.2
2.6
2.4
2.8
Spectral Index (b)
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3-Color Foregrounds at K Band (23 GHz)
Synchrotron Free-Free Thermal Dust
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3-Color Foregrounds at Ka Band (33 GHz)
Synchrotron Free-Free Thermal Dust
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3-Color Foregrounds at Q Band (41 GHz)
Synchrotron Free-Free Thermal Dust
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3-Color Foregrounds at V Band (61 GHz)
Synchrotron Free-Free Thermal Dust
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3-Color Foregrounds at W Band (94 GHz)
Synchrotron Free-Free Thermal Dust
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3-Color Foregrounds
K band (23 GHz)
Ka band (33 GHz)
Q band (41 GHz)
V band (61 GHz)
Synchrotron Free-Free Thermal Dust
W band (94 GHz)
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Best Fit Galactic Model
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Full Sky Guide
WMAP-detected point sources ( brightest)
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Foreground Spectra
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Foreground Template Removal
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CMB Anisotropy Power Spectra Dependence on
Cosmological Parameters
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Power Spectrum
(220.10.8, 74.70.5 mK)
cosmic variance limited for llt354
S/Ngt1 for llt658
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Power Spectrum
After Galactic Subtraction
Before Galactic Subtraction
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Unbinned Low-l Power Spectrum
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Correlation Function
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Power Spectrum Previous CMB Measurements
Angular Scale (deg.)
l(l1)Cl/2P (mK2)
Multipole Moment l
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Power Spectrum Previous CMB Measurements
Angular Scale (deg.)
l(l1)Cl/2P (mK2)
l(l1)Cl/2P (mK2)
Multipole Moment l
Multipole Moment l
Wang et al (2002) astro-ph/0212417
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Power Spectrum Prediction from 2dF Group
Angular Scale (deg.)
l(l1)Cl/2P (mK2)
l(l1)Cl/2P (mK2)
Multipole Moment l
Percival et al 2002, MNRAS, 337, 1068
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Temp x E-Polarization Power Spectrum
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CMB Polarization

• z20 reionization
• scattering of CMB from free electrons
• uniformly suppress lgt40 anisotropy by 30 (!)
• Now detected
• z1089 decoupling
• scattering of CMB from electrons with non-random
  velocities
• polarization correlates with temperature map
• 1st detected by DASI, now have power spectrum
• Gravity waves
• Inflation-generated gravity waves polarize CMB
• need CMBPOL

million years
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Millions of Cosmological Simulations Later
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Parameter Likelihood Functions
Cosmic Consistency!
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MAP Measures the Shape of the Universe
Shape of the Universe
Wtot 1.02 0.02
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Universal Content
WtotWbWcWL100
WmWbWc27 4
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Dark Energy Equation of State
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Limits on the Dark Energy Eqn of State
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WL vs. Wm
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Matter Fluctuations
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Big Bang

• Age 13.70.2 Gyr
• Expansion rate km/s/Mpc
• 7237 km/s/Mpc HST Freedman et al. (2001)
• Baryon density
• Wbh2 0.0224 0.0009
• Wb 0.044 0.004
• nb (2.50.1) x 10-7 cm-3

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INFLATION

• Flat Wtot1.020.02
• ns1 WMAP data only ns0.990.04
• All combined data ns0.960.02
• (or
  )
• Adiabatic isocurvature modes do not improve fit
• Gaussian random phases -58ltfNLlt134 (95 CL)
• TE anti-correlation velocities beyond horizon
  scale
• Tensor-to-Scalar ratio rlt0.71 (95 CL)
• (low gravity
  wave power)

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1965
Penzias and Wilson
1992
COBE
2003
WMAP
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http//lambda.gsfc.nasa.gov
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Papers Based On WMAP Data
WMAP Team submitted 13 papers to Astrophysical
Journal 1st outside papers using WMAP data 36
hours after release gt75 new papers, and growing
rapidly
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Summary

• Results from 1-year survey
• First detailed (0.2) full-sky CMB map
• First detection of polarization from reionization
• Reionization t0.170.04
• First measurement of TE cross power spectrum
• Newly observed anticorrelation is fresh evidence
  of inflation-like event
• New limits on non-Gaussianity
• -58 lt fNL lt 134 (95 CL)
• Support for Big Bang
• New support for Inflation
• Beginning to distinguish specific Inflation
  models
• Cosmic consistency, with new accurate set of
  numbers
• Intriguing hints?
• Very low anisotropy power gt60
• Running spectral index
• Bumps in power spectrum

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Future?

• More WMAP observations
• More other CMB measurements
• Other cosmological measurements (SN, SDSS,etc.)
• Planck mission (Silk damping,SZ)
• Gravity waves from inflation CMBPOL

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THE END
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Viewing the Decoupling Surface

• Ratio of heights of 1st and 2nd peaks gives
  baryon density
• Baryon density determines tdec3798 kyrs,
  zdec10891
• Sound horizon ctdec (size of blobs)

Wbh20.02240.0009
-7
Decoupling surface
q0.598 0.002
WMAP
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Inflation A Running Spectral Index?
COBE ns1.20.3
WMAPACBARCBI (MAPext) or WMAP2dF ns0.970.03
WMAP ns0.990.04
WMAPext2dFLya ns0.960.02
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Temperature-Polarization Correlation
Radial pattern around cold spots Tangential
pattern around hot spots
Temperature quadrupole at z1089 generates
polarization
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Future

• More WMAP observations
• Other CMB measurements
• Ground, balloon, Planck, CMBPOL
• Other cosmological measurements
• SN, SDSS, lensing, etc.
• Particle accelerators
• Lightest supersymmetric particle?
• Gravity waves (LISA, LIGO)
• Exciting times ahead!

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Best Cosmological Parameters Pg. 1
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Best Cosmological Parameters Pg. 2
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Reionization

• Energy emitted from, e.g. early stars, reionizes
  the universe
• Anisotropic scattering polarizes CMB
• WMAP measures total optical depth, t, of
  electrons that scatter CMB
• Ionization history theory can be matched against
  t
• Get and

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Total Power vs. Differential Radiometer
Total Power
Differential
symmetric differential common mode systematics
cancel rapid phase switching 2500 Hz chops
faster than gain instabilities pseudo-correlation
gain fluctuations are common to A and B and
cancel upon differencing.

• Physical temperature changes affect output
• Instabilities directly modulate the signal

Amplification
Detector
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