Discovery (1965): Hot Big Bang

Anisotropies (1992): Structure Formation

Acoustic Peaks (1998-2003): Inflation

Detailed Acoustic Peaks (2003-12): Cosmological Parameters

Dark Matter & Dark Energy

Why peaks and troughs?

• Vibrating String: Characteristic frequencies because ends are tied down

• Temperature in the Universe: Small scale modes begin oascillating earlier than large scale modes

Puzzle: Why are all modes in phase?

Power on a given scale is averaged over multiple modes with same wavelength.

We implicitly assumed that every mode started with zero velocity.

If they do all start out with the same phase …

Time/(400,000 yrs)

First peak will be well-defined

Clum

pine

ss

As will first trough ...

And all subsequent peaks and troughs

Clu

mp

iness

Time/(400,000 yrs)

If all modes are not synchronized though

First “Peak” First “Trough”

We will NOT get series of peaks and troughs!

Time/(400,000 yrs)Time/(400,000 yrs)

Clum

pine

ss

Clum

pine

ss

Coherent Peaks and Troughs Evidence for Inflation

Keisler et al. 2011

Evidence for New Physics

• Total matter density is much greater than baryon density non-baryonic dark matter

• Total matter density is much less than total density dark energy

Discovery (1965): Hot Big Bang

Anisotropies (1992): Structure Formation

Acoustic Peaks (1998-2003): Inflation

Detailed Acoustic Peaks (2003-12): Cosmological Parameters

Dark Matter & Dark Energy

What’s next?

What’s Next?

• Physics Driving Inflation• Neutrino Masses and Abundances• Nature of Dark Energy

Non-Gaussianity

)%95(631

)%95(804

CLf

CLf

NL

NL

Current observations

WMAPSDSS

Smith, Senatore, & Zaldarriaga (2009)Slosar et al. (2008)

205

53

NL

NL

f

f

Upcoming observations

PlanckDES

If local NG is found in the next decade, single field models of inflation will be falsified

Dozens of experiments going after B-modes

QUIET: Araujo et al. 2012

Ambitious Plans for the coming Decade

Gravitational Waves Elsewhere

Dodelson, Rozo, & Stebbins (2003)Sarkar et al. (2008)

Dodelson (2010)Masui & Pen (2010)

Book, Kamionkowski, & Schmidt (2011)

Primordial Gravitational Waves

also produce lensing B-modes. B-mode lensing

(call it ω) spectrum peaks on the largest

scales*

GW wave signal

Scalar leakage

Noise Estimate

*Might be good way to test for bubble collisions predicted by eternal inflation

Gravitational Waves Elsewhere

The same gravitational wave that sources polarization after reionization also

transforms the shapes of galaxies: these two signals are correlated!

Cross-Correlation is non-negligible

Depends on l and redshift of source

galaxies; might devise weighting scheme to

optimize signal. Detection would

eliminate systematics.

Additional Neutrino Species

WMAP

Damping Scale and Sound Horizon

Effect of adding extra neutrinos (Hou et al. 2011)

• H-1 goes down• Ratio of damping scale to sound

horizon goes up• Sound horizon is fixed so damping

scale goes up, gets larger• Suppression kicks in at lower l• Power spectrum in the damping

tails goes down

Power in the Tail of the CMB is (a little) low

Keisler et al. 2011

Current Constraints

SPT favors high Neff (as do other small scale CMB expeirments)

Preliminary SPT Spectrum

Look for tighter neutrino constraints and constraints on n’

Secondary Anisotropies

Scattering off electrons Gravitational Lensing

kSZ: ReionizationThermal SZ: Clusters, LSS Cosmic Shear

Cluster Lensing

Lensing of the CMB

Hu 2002

CMB photons from the last scattering surface are deflected (~few arcminutes) by coherent large scale structure (~few degrees)

Effect is not as dramatic in real maps, but estimators of non-Gaussianity extract projected gravitational potential

Lensing of the CMB

Primordial unlensed temperature Tu is re-mapped to

where the deflection angle is a weighted integral of the gravitational potential along the line of sight

Lensing of the CMB

Consider the 2D Fourier transform of the temperature

Now though different Fourier modes are coupled! The quadratic combination

would vanish on average w/o lensing. Because of lensing, it serves as an estimator for the projected potential

where

Lensing of the CMB

Atacama Cosmology Telescope

Das et al. 2011

ACT, a high resolution experiment, has detected lensing of the CMB and estimated the power spectrum of the lensing structures

Matter-only model predicts more structure

Lensing of the CMB

Sherwin et al. 2011

Lensing amplitude + primary acoustic peak structure provide evidence for acceleration from the CMB alone at 3.2 sigma

South Pole Telescope has detcted this at > 6-sigma

Van Engelen et al 1202.0546

Planck and then ACTPol & SPTPol will make 30- or

40-sigma detections within

the next few years. We are

approaching the lower limit of 0.05

eV!

Difference between massless spectrum and one

with 0.1 eV

Hall & Challinor 2012

Clusters and Dark Energy

• Cluster abundance depends on geometry (volume as function redshift) and growth of structure (exponentially sensitive to σ8): excellent probe of Dark Energy

• Key Systematic: Mass Calibration• CMB can help by observing: Thermal SZ Effect

(Small scatter between mass and SZ signal) and CMB-Cluster Lensing (Direct determination)

Sunyaev-Zel’dovich Effect

13,823 Clusters in SDSS 12.6 M pixels of 3.4’ size

Challenge: Large WMAP pixels

Sunyaev-Zel’dovich Effect

Non-parametric Average T in annuli around massive (blue) and less massive (red) clusters. Compare to predictions accounting for CMB noise. Result: smaller signal than expected

Sunyaev-Zel’dovich Effect

Parametric Use a template for the signal and fit for the free amplitude (matched filter). Signal smaller than predicted … in agreement with Planck

Cluster-CMB Lensing

Initial papers (Zaldarriaga 1999) pointed to distinctive signal: lensing a dipole. Hot side is slightly cooler since photons arrive from farther away; cool side is slightly hotter. Remove the dipole dimples

Likelihood Approach

Amplitudes of lensing and SZ signal

Data in pixel iSZ Template in pixel i

with covariance matrix that depends on the deflection angle

Works well when using correct templates

SPT parameters (beam, noise, sky coverage, cluster count)

Works less well when applied to independently generated mocks with

different lensing templates and scatter

Conclusion

• Inflation: Look for upcoming results on physics of inflation (B-modes, Non-Gaussianity, n’)

• Neutrinos: Tantalizing results for Neff and capable of discovering inverted hierarchy

• Dark Energy: – Evidence from CMB only– Will help propel clusters to viable DE probe

Knox & Song; Kesden, Cooray, & Kamionkowski 2002

Clean up B-mode contamination and measure even small tensor component

Probe inflation even if energy scale is low

What can we do with this?

Non-Gaussianity: Large Scale Bias

Local Non-Gaussianity corresponds to:

)()()( 2 xfxx GNLG

Dalal et al. (2008) showed that this leaves a characteristic imprint on large scale structure

Non-Gaussianity: Large Scale BiasNon-Gaussianity: Large Scale Bias

Consider the density field in 1D. A given region is collapsed (i.e. forms a halo) if the density is larger than a critical value.

Critical density

Long Wavelength mode

Non-Gaussianity: Large Scale BiasNon-Gaussianity: Large Scale Bias

Add in short wavelength modes. For this one realization, the second peak has collapsed into a halo.

Non-Gaussianity: Large Scale BiasNon-Gaussianity: Large Scale Bias

More generally, short wavelength modes drawn from a distribution with given rms (red curves)

Halos more likely to form in region of large scale overdensity = bias

Non-Gaussianity: Large Scale BiasNon-Gaussianity: Large Scale Bias

Change with primordial NG: more small-scale fluctuations in region of large scale over-density more bias on large scale

Non-Gaussianity: Large Scale Bias

Slosar et al. (2009)

100NLf

Non-Gaussianity ElsewhereNon-Gaussianity Elsewhere

Reionization proceeds more rapidly in NG models (Adshead, Baxter, Dodelson, Lidz 2012)

Non-Gaussianity ElsewhereNon-Gaussianity Elsewhere

May learn about inflation from surveys from infrared or 21 cm observations