CMB Science

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• CMB Science
• and
• Observations
• K. Ganga

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The CMB

• The CMB is a blackbody at T 2.73 K.
• The most prominent anisotropy in the CMB, with
  amplitude of about 0.1, is due to our motion
  with respect to the CMB rest frame.
• Further anisotropies are at the level of 0.001
  and lower (or much lower)

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The CMB again...
Thanks to A. Taylor
Recombination
Recombination
Horizon 1o
Plasma
Plasma
Plasma
Gravitational lensing
T2.73K
T2.73K
Reionisation
Observer
Observer
z 1000
z infinity
z 1000
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?T on super-horizon scales (gt1o)

• Sachs-Wolfe Effect Gravitational redshift due to
  photons climbing out of potential wells,

A. Taylor
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Acoustic Oscillations
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Measuring Curvature
Flat
?1
Closed
?2
B. Crill
Open
?3
Acoustic horizon (same for all)
J. Ruhl
?vs tdec
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Baryons change the effective mass
W. Hu
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How Parameters are Fit
Angular spectrum varies mostly with ?8,
?b????cdm?????H0,???ns
Parameters are found by making spectra for the
range of models of interest and finding which
has the best chi-squared given the actual data
and some prior information.
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'Degeneracies' require other data
Simulated Pretty flat models
lpeak?200 ?0-1/2
?tot 1
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A little help from our friends...
From Lewis Bridle 2002 Red Pre-WMAP CMB
data Blue CMB data w/ HST Yellow CMB data w/
HST, 2dF,
BBN
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The CMB Temperature Power Spectrum
WMAP/ Acbar/ BOOMERanG/ CBI/ VSA
Archeops/ARGO/ATCA/BAM/DASI/ DMR/FIRS/IAB/MAX(IMA)
/OVRO/ Python/QMAP/Relict/Saskatoon/ South
Pole/Tenerife/Toco/Viper/ White Dish/...
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Quadrupole Scattering
e-
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Polarization has been measured
DASI, CBI, BOOMERanG and CAPMAP have all
published polarization detections.
WMAP
DASI
Lens
IGW
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Parameters
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The E/B Decomposition

• Can decompose Q U into
• E-modes (even-parity)
• (or grad)
• B-modes (odd-parity)
• (or curl)
• E-modes produced by all quadrupole sources
  (velocity gradients and gravitational waves)
• B-modes produced by gravitational waves and
  lensing of E-modes

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Lensing transform E to B

• Converts E-modes to B-modes
• Confusion limit to measuring the gravitational
  wave component
• Interesting signal in itself, probing growth of
  structure from present-day to epoch of decoupling

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Inflation Constraints
V???
?
Einflation mplr¼
Liddle Lyth, 2000
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Predicted Spectra
TT
EE
Lens
BB
T/S0.05
T/S0.005
IGW
T/S0.0005
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Future Observations
Lawrence, C.R., Proceedings of Science (CMB2006)
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The Planck HFI

• 50 feeds in a focal plane of 1kg at 100mK
• Focal plane area 2 square degrees
• Instantaneous sky coverage per polarization-sensit
  ive frequency about 0.1 square degrees

The HFI also has channels at 100, 545 and 850 GHz
that are not polarization sensitive
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Predicted Planck Measurements
r0.1,t0.17
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How to go deeper

• Planck can detect r0.1
• Planck is 2 times BLIP
• Planck has 10 detectors covering 0.1 degree2
  per frequency
• Planck observes 1 yr.
• In the BLIP limit,ignoring cosmic variance, ?r
  s2 (NdetectorsTime)-1

• A future mission should
• Achieve BLIP
• Observe longer (2)
• 2 for satellites
• John will discuss ground-based
• Use many more pixels
• To go much deeper, we must use arrays.

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Example EPIC
J. Bock
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WMAP Foregrounds
74.3 of sky
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BOOMERanG and CBI Measurements
Neither BOOMERanG nor CBI have detected any BB at
the level of the EE polarization signals. This
limits the foregrounds in their regions.
Montroy, et al.
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Fin
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Symmetry?
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WMAP w versus k
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WMAP w versus m