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)