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Cosmology After WMAP

Cosmology After WMAP. David Spergel Cambridge December 17, 2007. 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

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Cosmology After WMAP

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  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 UCLA Ned Wright Princeton Chris Barnes Norm Jarosik Eiichiro Komatsu Michael Nolta Chicago Stephan Meyer UBC Mark Halpern 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

  9. 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

  10. Polarization measurements

  11. 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. 2007 Kuo et al. 2007 Kuo et al. 2007

  12. SDSS and Baryon Wiggles • Purely geometric test (SDSS + WMAP) Eisenstein et al. (2005)

  13. 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

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

  15. ACT Observing Program • Cover ~1000-2000 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

  16. 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

  17. Fluctuations Appear to be Gaussian

  18. FOREGROUND CORRECTED MAP

  19. Non-Gaussianity Caveat Emptor • Check for foregrounds • 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

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

  21. Dust everywhere….

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

  23. fNL in WMAP Data? • Foreground contamination is very worrying! • Need null tests! • Detector noise • Foregrounds • A2 Idust? AB Idust?…

  24. fNL in WMAP Data? 62% of data • Statistical significance overestimated (choose highest amplitude cut and frequency combination) • Most of the signal is coming from triangles that don’t have most of the S/N! • S/N goes up as errors goes up! Adding very noisy data increases the signal Minimum variance 2/3 of data Minimum variance

  25. fNL Conclusions • 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

  26. 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

  27. THANK YOU !

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