Cosmology After WMAP. David Spergel Cambridge December 17, D. Spergel

Transcription

1 Cosmology After WMAP David Spergel Cambridge December 17, 2007

2 Wilkinson Microwave Anisotropy Probe A partnership between NASA/GSFC and Princeton Science Team: NASA/GSFC Chuck Bennett (PI) -> JHU Michael Greason Bob Hill Gary Hinshaw Al Kogut Michele Limon Nils Odegard Janet Weiland Ed Wollack Brown Greg Tucker UBC Mark Halpern UCLA Ned Wright Chicago Stephan Meyer Princeton Chris Barnes Norm Jarosik Eiichiro Komatsu Michael Nolta Lyman Page Hiranya Peiris Rachel Bean David Spergel Olivier Dore Licia Verde Jo Dunkley

3 K - 22GHz

4 Ka - 33GHz

5 Q - 41GHz

6 V - 61GHz

7 W - 94GHz

8 Q band V band W band

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10 We now have a standard cosmological model General Relativity + Uniform Universe Big Bang Density of universe determines its fate + shape Universe is flat (total density = critical density) Atoms 4% Dark Matter 23% Dark Energy (cosmological constant?) 72% Universe has tiny ripples Adiabatic, nearly scale invariant, Gaussian Fluctuations

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13 Polarization measurements

14 Consistent Cosmology Large-scale structure Cluster counts Weak Lensing Strong Lensing Stellar Ages Big Bang Nuclesynthesis (Li?) Hubble Constant Velocity Fields Small-scale CMB Oguri et al ^âé xà täa ECCJ Kuo et al. 2007

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16 SDSS and Baryon Wiggles Purely geometric test (SDSS + WMAP) QuickTime and a TIFF (LZW) decompressor are needed to see this picture. QuickTime and a TIFF (LZW) decompressor are needed to see this picture. Eisenstein et al. (2005)

17 Atacama Cosmology Telescope Operational! Scanning 200 square degrees/night Nearly 1000 working detectors, each with sensitivity greater than WMAP Currently at 145 GHz 3 frequencies in March 2008 QuickTime and a decompressor are needed to see this picture. QuickTime and a decompressor are needed to see this picture.

18 Simulations of mm-wave data. Survey area <1% 2% High quality area 150 GHz SZ Simulation MBAC on ACT 1.7 beam 2X noise MAP PLANCK PLANCK

19 ACT Observing Program Cover ~ square degrees Overlap areas with significant amount of astronomical data (SDSS Stripe 82, DLS and CFHT deep fields) Cross-correlate lensing of CMB and galaxies Kinetic SZ Thermal SZ Understand sources

20 Hunting for Non- Gaussianities Axis of Evil (Land and Maguiejo) Cold Spot (Cruz et al.) Too few cold and hot spots (Larson and Wandelt) Vorticity and Shear Features in the power spectrum Bianchi VIIh models Alignment of quadrupole and octopole

21 Fluctuations Appear to be Gaussian

22 FOREGROUND CORRECTED MAP

23 Non-Gaussianity Check for foregrounds Caveat Emptor Foregrounds dominate the full sky maps (and the ILC map in the plane is not intended for scientific analyses) Foregrounds are highly non-gaussian and low level foregrounds can contaminate statistics Check statistical significance Number of tests and free parameters Monte-Carlo Simulations Check noise statistics

24 CMB Foregrounds are significant at all frequencies Synchrotron Thermal Dust Free-Free Emission Point Sources Spinning Dust Foregrounds are dominant for polarization maps

25 Dust everywhere.

26 Primordial Skewness Komatsu and Spergel 2001 Sym terms Bispectrum changes sign as a function of l!

27 f in NL WMAP Data? Foreground contamination is very worrying! Need null tests! Detector noise Foregrounds A 2 I dust? AB I dust?

28 f NL in WMAP Data? NL 62% of data Statistical significance overestimated (choose highest amplitude cut and frequency combination) Most of the signal is coming from triangles that don t t have most of the S/N! S/N goes up as errors goes up! Adding very noisy data increases the signal 2/3 of data Minimum variance Minimum variance

29 f Conclusions NL Physically reasonable Yadav,, Komatsu et al. estimator improves sensitivity Yadav and Wandelt claim overestimates statistical significance, however, does show intriguing hint (perhaps of foreground contamination) Predictions of bispectrum and trispectrum are interesting Can be distinguished from other forms of non- Gaussianity

30 Cosmology Now Has A Standard Model Basic parameters are accurately determined Many can be measured using multiple techniques CMB best fit now consistent with other measurements Mysteries remain: dark matter, dark energy, physics of inflation Next step: Probe Physics Beyond the Standard Model

31 THANK YOU!