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WMAP: Recent Results and Dark Energy. L. Page, STScI, May 2008. A 6 parameter model agrees with virtually all cosmological measurements regardless of redshift or method. - PowerPoint PPT Presentation
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WMAP: Recent Results and Dark Energy
L. Page, STScI, May 2008
A 6 parameter model agrees with virtually all cosmological measurements regardless of redshift or method.
The model assumes a flat geometry, a new form of matter, something that mimics a cosmological constant, and a deviation from scale invariance ( =1, ~2.5-3).
WMAP5 only
Models based on some kind of field theory of the early universe predict ns.
WMAP5 + SN& BAO
What does the CMB ALONE tell us about
Dark Energy?
NOTHING!(one more bit of information is needed)
“Geometric Degeneracy”
CMB alone tells us we are on the “geometric degeneracy” line
Reduced
closed
open
Assume flatness
WMAP5 only best fit LCDM
{WMAP3
WMAP5= 1.045
Lewis & Bridle ’02
What’s new for WMAP5?
•Calibration uncertainty now 0.2% (Hinshaw et al. 2008)
•Full reanalysis of the main beam profiles, near lobes, and sidelobes (Hill et al. 2008). 1% shift in solid angle, uncertainties halved.
•Developed new foreground cleaning methods for temperature (Gold et
al. 2008) and polarization (Dunkley et al. 2008). However, basic results use original methods.
•Nominal sky mask updated to “KQ85” (keeps 85%) vs Kp2 (keeps 97%) plus ~750 sources. (Gold et al., Wright et al. 2008)
Selected highlights:
Why care about the beam profiles?
Three different spectra that differ only in spectral index.
The black line is the best WMAP model.
Spectral Index
Normalize the spectra to l=220 (mimics ns-amplitude degeneracy)
The two window functions are for 0.1 deg FWHM beams with a 1% difference in solid angle. Only WMAP has achieved anything like this accuracy.
Spectral Index
Divide by fractional window function.
Conclusion: To probe the index the beams need to be understood to the 1% level.
In addition, there are astrophysical challenges.
Full beam reanalysis led to:
Consistent with earlier error bars but systematically higher.
Hill et al. 2008
The Data23 GHz
33 GHz
41 GHz
61 GHz
94 GHz
WMAP5-WMAP3
Hinshaw et al. 2008
125 mK
67 mK
48 mK
24 mK
17 mK
WMAP5 TT&TE Spectra
3 yr
Nolta et al, Hinshaw et al. 2008
Particle horizon at decoupling
ACBAR and CBI go to l=3000
New Polarization
Maps
Hinshaw et al. 2008
EE Power Spectrum
Nolta et al. 2008
After accounting for foreground emission, the BB, EB, TB spectra are all consistent with zero.
Uncertainties include cosmic variance.l by l
Optical Depth,
The square of the optical depth is essentially the average of the low l EE data.
Of course, the quoted values come from the full analysis.
Hinshaw et al. 2008
Analysis of curvature (and thus the presence of w=-1 Dark Energy)
With the HST prior, h=0.72 +/- 0.08,
-0.052< <0.013 (95%cl)
k
By adding BAO and SNIa, we find:-0.0181 < Ωk < 0.0071 (95% CL)
Can convert to limits on the curvature radius of the universe: For negatively curved space (Ωk>1): R>23/h Gpc For positively curved space (Ωk<1): R>36/h Gpc Komatsu et al 2008
Now add BAO and supernovae
For combined data, w= -0.97 +- 0.06Komatsu et al 2008
Now relax flatness and w=-1 assumptions
Need both SN and BAO to limit the curvature and the dark energy equation of state
No significant running index is observed. WMAP-only: dns/dlnk = -0.037 +/- 0.028 WMAP+BAO+SN: dns/dlnk = -0.032 +/- 0.020
Early Universe: WMAP consistent with power law
(Note that 1 parameter is added)Dunkley et al 2008
Komatsu et al 2008
Use WMAP to constrain tensor-to-scalar ratio: tensors produce B-mode polarization, but also a large-scale temperature signal. (Currently low-l BB limits r < 20)
Early Universe: Limits on Gravitational Waves
Dunkley et al 2008 • With all data: r < 0.20 (95% CL)
Komatsu et al 2008
NASA/GSFCBob Hill Gary Hinshaw Al KogutMichele LimonNils OdegardJanet WeilandEd Wollack
PrincetonNorm Jarosik Lyman PageDavid Spergel
UBCMark Halpern
ChicagoStephan MeyerHiranya Peiris
BrownGreg Tucker
UCLANed Wright
Science Team:
WMAPA partnership between NASA/GSFC and Princeton
Johns HopkinsChuck Bennett (PI)Ben GoldDavid Larson
CornellRachel Bean
MicrosoftChris Barnes
CITAOlivier DoreMike Nolta
UABLicia Verde
UT AustinEiichiro Komatsu
QuickTime™ and aCinepak decompressor
are needed to see this picture.
OxfordJo Dunkley
THANK YOU
Non-GaussianityThe quadrupole is not anomalously low. For the full sky, the 2-pt correlation function is not anomalous.
Most “detections” of non-Gaussianity are based on a posteriori statistics. That is, one seeks any oddity in the maps and quantifies it.
The North-South asymmetry was visible in the COBE data.
It would be wonderful to find a clear signature of cosmic non-Gaussianity. The WMAP team has not found one yet.
Non-Gaussianity
• Look for non-Gaussianity by looking for non-zero bispectrum = 3 point function
• Define ‘fNL’ using curvature fluctuations: Φ(x)=Φgauss(x)+fNL[Φgauss(x)]2
• -9 < fNL(local) < 111 (95% cl) (Komatsu et al 2008)
• -151 < fNL(equilateral) < 253 (95% cl) (Komatsu et al 2008)
A significant fraction of the full-sky quadrupole comes from:
Extra cold spot: (Vielva et al. 2004, Cruz et al. gave 1.8% prob. 2005)
(Hajian 2007)
Note “fingers” present in the southern Galactic hemisphere. Largest effect in almost ecliptic coord.
Detection of SH persists!
Alignment? (de Oliveira-Costs et al. 2004)