# Presentation: 095796

## CMB:  An Overview

- Lloyd Knox (UC Davis)
- Cosmo 2002
- Chicago, 18 September 2002

**UC Davis**
**Mike Chu**
- Manoj Kaplinghat*
- Dana Nuccitelli
**Alan Peel* **
**Yong-Seon Song**

**Elsewhere**
- Olivier Dore (Princeton)
- Zoltan Haiman (Princeton)
- Gil Holder (IAS)
- Martin White (UC Berkeley)

- *for hire

**Notes:**
Get dkp02 and Kaplinghat et al. 2002 onto computer.

## CMB:  An Overview

- CMB  Basics
- What we have learned already (from     )
- Prospects for the future
- Improved temperature measurements
- Polarization measurements
- Sunyaev—Zel’dovich Effects

## Slide 3

## Slide 4

## Slide 5

- Wang, Tegmark & Zaldarriaga (2001)

- Why study this power spectrum?
- Calculable --- linear perturbation theory is highly accurate.
- Rich features

- Large angular scales

- small angular scales

- COBE/DMR DASI Boomerang Maxima       +others

- peaks point to characteristic scale:  angular size of sound horizon

- Peak morphology controlled by
- Baryon density which affects pressure of fluid
- Total matter density which affects gravitational driving of oscillations
-  Excellent probe of baryon density and dark matter density

## What We’ve Learned

- Qualitative Results:
- Structure formed from adiabatic nearly scale—invariant “initial” spectrum of fluctuations
- Spatial geometry is flat (or at least nearly so)
- Supernovae—independent evidence for dark energy
- Age of Universe is 14.0 \pm 0.5 Gyrs (assuming flatness)

## The Universe is not Defective

- Structure formed via gravitational instability
- Seed perturbations were formed early (inflation) rather than continually (topological defects)

***defects***

## The Curvature Radius 

## Supernovae—Independent Evidence for Dark Energy

- 

- And if

- then

## Quantitative: Parameter Bounds

|  | 0.021 | 0.002 |
| --- | --- | --- |
|  | 0.15 | 0.02 |
| A (arbitrary units) | 6.7 | 0.6 |
|  | 0.96 | 0.04 |

- Mean

- Std. Dev.

| DASI
calibration | 1.00 | 0.03 |
| --- | --- | --- |
| BOOM
calibration | 1.07 | 0.03 |
| Maxima
calibration | 1.00 | 0.03 |
| BOOM
fwhm | 13’.9 | 0’.3 |

- Mean

- Std. Dev.

- Also varied, but not well—constrained:

- Knox, Christensen and Skordis (2001)

- We use MCMC (Christensen et al. 2001) and DASh (Kaplinghat, LK and Skordis 2002)

## Prospects for the future

- Improved temperature measurements
- Polarization measurements
- Reionization
- Gravity wave detection
- Lensing potential reconstruction as dark energy probe
- See DASI talk tomorrow
- Sunyaev—Zel’dovich Effects

## Improved Temperature Measurements from MAP, ACBAR*, Planck, ...

- Light blue:  MAP (Jan 2002)
- Dark blue:  Planck (2009)

- Present

- Future

- *Watch for ACBAR with tight high ell results this fall.

- Compilation by Lewis and Bridle

- Eisenstein, Hu and Tegmark 1998

- Tremendous leaps in precision

- See recent Frieman et al. for one example of what to do with all this precision.

## CMB Polarization

- Unpolarized radiation with a quadrupole moment scattering off of free electrons results in linearly polarized radiation.

- No Q at z > ~1100 (fast scattering isotropizes the radiation field)

- No free electrons at   ~7 <  z < ~1100

- z

- 1100

- 1

- 10

- polarization generation

## Polarization

- Eisenstein, Hu and Tegmark 1998

- Light blue:  MAP
- Dark blue:  Planck

- P amplitude about 10% of T anisotropy
- l > 15 from last—scattering surface
- l < 15 from reionization

- We will discuss reionization feature first.
- Detecting it is important for determining amplitude of primordial fluctuations.
- MAP will see it well enough to determine primordial amplitude to 4% (Kaplinghat et al. 2002)

## Detection of a GOP Trough

- # of Republican Presidents in White House

- 1

- 0

- 1982                   1986                   1990                   1994

- Does it signal the end of the dark ages?

## GP Trough  Detection of Dark Age?i.e., Do Quasar Spectra Really Imply Reionization at z=6.3?

- GP trough due to x_HI > 0.001 so x_e can still be quite large
- Rapid transition appears to be happening near z=6.3, but is it from x_e =0 or x_e=0.5?
- CMB polarization observations are uniquely qualified to answer these questions.

- Kaplinghat, Chu, Haiman, Holder and Knox (2002)

- Becker et al. (2001)

## Beyond 

- Redshift 

- 6.3

- 1

- 0

- Kaplinghat et al. (2002)

- MAP

- Planck

- No noise

## Gravitational Wave Generates Temperature Anisotropy and Polarization

- Resulting temperature pattern

- Also leads to polarization since unpolarized quadrupole radiation scattered by an electron results in polarization.

- Imagine a single GW propagating out of the screen, compressing and stretching space as shown by arrows.

## Detecting Gravitational Waves

- Knox & Song, PRL (2002) ;  Kesden et al. PRL (2002)

- Hu and Okamoto, 2002 lensing potential reconstruction

-  The “B mode” polarization pattern is not generated by scalar perturbations in linear perturbation theory.

- Lensing—induced scalar B mode

- Residual scalar B mode power

## Lensing

- Harmonic effects of lensing:
-      1) creates B out of E (and vice—versa)
-      2) leads to correlation between

- Use to build estimator for

- Hu (2001), Hu and Okamoto (2002)

## Power Spectrum of the Lensing Potential

- Hu  (PRD 2002)

- Planck:  dark blue error boxes

- No noise:  light blue error boxes

- w=-1
- w=-0.8
- w=-0.5

- Kaplinghat, Song and Knox (2002)

## Dark Energy Constraints from CMB Lensing

- No Noise

- Planck

- one sigma
- two sigma

-   l<500
- l<1000

- Polarization is essential to achieving these significantly tighter bounds.

- Kaplinghat, Song and Knox (2002)

- Kaplinghat, Song and Knox (2002)

- Hu (PRD 2002)

## One Final Note on Polarization:

- Go see the DASI talk tomorrow!

## Sunyaev—Zeldovich Effects

- Optical image  of Hydra A from La Palma and B. McNamara

- Chandra image of Hydra A

- Thermal SZ effect is a spectral distortion proportional to

- Thermal SZ difference from Planck law

- LK+Dore, Nuccitelli, Peel & White

- S. Church

## Multi-nu Thermal SZ

- 30 GHz

- 70 GHz

- 353 GHz

- 545 GHz

- 857 GHz

- 217 GHz

- 144 GHz

- S. Church

- Peel, Nuccitelli, LK, White (2002)

## Applications of SZ Effects

- Angular diameter distance 
- One-point function and two-point function as functions of z 
- Radial peculiar velocities
- 3 D gravitational potential reconstruction
- Two-point function 

- Note:  using clusters for precision cosmology will require X-ray, weak lensing and optical input as well.

- Reese et al. (2002)

- Haiman et al. (2000), Holder  et al. (2001)

- Peel and Knox (2002)

- Dore, Knox and Peel (2002)

## SZ Science Already Being Done

- At BIMA
- With SuzIE
- With CBI

- Bond et al. (CBI, 2002)

- Dawson et al. (2002)

## Planned SZ Experiments

- ...also Planck!

## Summary and Conclusions

- Applicability of linear theory  CMB is our cleanest cosmological probe
- Rich features in C_l  a powerful probe
- We have learned much already
- Structure formed from adiabatic nearly scale—invariant “initial” spectrum of fluctuations
- Spatial geometry is flat (or at least nearly so)
- Supernovae—independent evidence for dark energy
- Age of Universe is 14.0 \pm 0.5 Gyrs (assuming flatness)
- There is still much  more to come