Transcript WMAP & The Emerging Standard Cosmological Model

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
Janet Weiland
Ed Wollack
Brown
UCLA
Greg Tucker
Ned Wright
UBC
Mark Halpern
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
K - 22GHz
Ka - 33GHz
Q - 41GHz
V - 61GHz
W94GHz
Q band
V band
W band
We now have a standard
cosmological model
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General Relativity + Uniform
Universe
Big Bang
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Density of universe
determines its fate + shape
Universe is flat (total density =
critical density)
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Atoms 4%
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Dark Matter 23%
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Dark Energy (cosmological
constant?) 72%
Universe has tiny ripples
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Adiabatic, nearly scale
invariant, Gaussian
Fluctuations
Polarization measurements
Consistent Cosmology
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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
SDSS and Baryon Wiggles
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Purely geometric test
(SDSS + WMAP)
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Eisenstein et
al. (2005)
Atacama Cosmology
Telescope
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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
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Simulations of mm-wave data.
 1%
1.4
Survey area
0
 2%
High quality area
150 GHz
SZ Simulation
MAP
MBAC on ACT
1.7’ beam
2X noise
PLANCK
PLANCK
ACT Observing Program
 Cover
~1000-2000 square degrees
 Overlap areas with significant amount of
astronomical data (SDSS Stripe 82, DLS
and CFHT deep fields)
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Cross-correlate lensing of CMB and galaxies
Kinetic SZ
Thermal SZ
Understand sources
Hunting for NonGaussianities
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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
Fluctuations Appear to be
Gaussian
FOREGROUND CORRECTED
MAP
Non-Gaussianity
Caveat Emptor
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Check for foregrounds
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Check statistical significance
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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
Number of tests and free parameters
Monte-Carlo Simulations
Check noise statistics
CMB Foregrounds are
significant at all frequencies
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Synchrotron
Thermal Dust
Free-Free Emission
Point Sources
Spinning Dust
Foregrounds are
dominant for
polarization maps
Dust everywhere….
Primordial Skewness
Komatsu and Spergel 2001
Sym terms
Bispectrum changes sign as
a function of l!
fNL in WMAP Data?
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Foreground
contamination is very
worrying!
 Need null tests!
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Detector noise
Foregrounds
A2 Idust? AB Idust?…
fNL in WMAP Data?
62% of data
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Statistical significance
overestimated (choose highest
amplitude cut and frequency
combination)
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Minimum
variance
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
2/3 of data
Minimum
variance
fNL Conclusions
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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 nonGaussianity
Cosmology Now Has A Standard Model
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Basic parameters are accurately determined
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Many can be measured using multiple techniques
CMB best fit now consistent with other
measurements
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Mysteries remain: dark matter, dark energy,
physics of inflation
 Next step:
Probe Physics Beyond the Standard Model
THANK YOU !