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ACTACT Atacama Cosmology Atacama Cosmology

TelescopeTelescope Funded by NSFFunded by NSF Will measure CMB Will measure CMB

fluctuations on small fluctuations on small angular scalesangular scales

Probe the primordial Probe the primordial power spectrum and the power spectrum and the growth of structuregrowth of structure

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The The MMillimeterillimeter BBolometric olometric AArrayrray CCamera: amera: 3000 Detectors3000 Detectors

Tricolor: 145, 225, & 265 GHz

3 independent 32x32 arrays

TES PUDs from GSFC•PUDs = Pop-Up Devices

•TES = Transition Edge Sensor Each pixel: 1 mm x 1 mm

TDM Multiplexing •2-stage 1x33 mux chips, followed by Series Array SQUIDs: SAs -- from NIST

•Nyquist inductors -- from NIST

•Mux servo electronics & DAQ from UBC (who provided these for SCUBA)

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ACT COLLABORATIONSACT COLLABORATIONS

SchoolsGovernment Labs Museums

…united through research, education and public outreach.

PENN

Haverford

Princeton

CUNYTorontoCatÓlica

Kwa-Zulu Natal

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Simulations of mm-wave data.

1.401%

2%

Survey area

High quality area

150 GHz SZ Simulation MBAC on ACT 1.7’ beam2X noise

PLANCK

MAP

PLANCK

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Where will we Where will we be with CMBbe with CMB

Bond et al.

astro-ph/046195

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Cosmic Timeline for ACT ScienceCosmic Timeline for ACT Science

z = 1000t = 4 x 104 yrs

z = 7t = 3 x 106 yrs

z = 1t = 1 x 109 yrs

z = .25t = 12 x 109 yrs

now

• First galaxies • Universe is reionized• Ostriker-Vishniac

•Surveys of Sunyaev-Zel’dovich (SZ) clusters• Diffuse thermal SZ• Kinetic SZ signal

• Initial conditions for structure formation

• N(mass,z) – Evolution of Cosmic Structure• Lensing of the CMB• The growth of structure is sensitive to w and mn

• Additional cross-checks from correlations among effects

• Extraction of cosmological parameters

Primary CMB CMB Lensing OV/KSZ Diffuse Thermal SZ Cluster Surveys

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SZ SignatureSZ SignatureHot electron gas imposes a unique spectral signature

NO SZ Contribution in Central Band

145 GHzdecrement

220 GHznull

270 GHzincrement

1.4°x 1.4°

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Coordinated Cluster Coordinated Cluster MeasurementsMeasurements

Identify and measure >500 clusters in an

unbiased survey with multi-wavelength observations

Galaxy Cluster

HOT Electrons

• Mass limits of 3 x 1014 estimated from simulations• Science derived from N(mass,z)

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Southern Africa Large Southern Africa Large TelescopeTelescope

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SALT has achieved 1” seeing

World’s Largest Optical Telescope

SALT will survey the ACT strip in 4 colors and will then measure spectra for tens of galaxies per cluster

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1313

CMB

-1850

(K)

0

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Lensing of the CMBLensing of the CMB

1.4°x 1.4°

• Lensing arises from integrated mass fluctuations along the line of sight.

• The CMB acts as a fixed distance source, removing the degeneracy inherent to other lensing measurements.

• Signal at l = 1000-3000

• Image distortion – only a minor effect in the power spectrum.

• Must have a deep, high fidelity map to detect this effect.

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Lensing of the CMBLensing of the CMB-34

(K)

0

34

1.4°x 1.4°

Lensing Signal

• RMS signal well above noise floor.

• Isolate from SZ and point sources spectrally.

• Identify with distinctive 4-point function.

2% of CMB RMS

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Where are the baryons?Where are the baryons?

Cross-correlate galaxy counts and kinetic Cross-correlate galaxy counts and kinetic SZ signalSZ signal KSZ signal proportional to KSZ signal proportional to vv

• Measure TMeasure TKSZKSZ^2 as a function of galaxy position^2 as a function of galaxy position

• Use redshift distribution to predict v, correlate Use redshift distribution to predict v, correlate density/velocity field and measure density/velocity field and measure

Estimates suggest high S/N detection for ACT Estimates suggest high S/N detection for ACT and should be much better for 1 mm CCATand should be much better for 1 mm CCAT

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ACT \REGION: Target for ACT \REGION: Target for future lensing surveysfuture lensing surveys

ACT will begin surveying in 2006

We already plan deep multi-band imaging with SALT of low extinction part of ACT strip (200 square degrees)

Would be a very interesting target for a lensing survey

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ACT is but one of several next ACT is but one of several next generation CMB experimentsgeneration CMB experiments

APEX (Atacama APEX (Atacama Pathfinder Experiment)Pathfinder Experiment)

UCB/MPIUCB/MPI 1.4mm and 2 mm obs.1.4mm and 2 mm obs. SZ scienceSZ science

SPT (South Pole SPT (South Pole Telescope)Telescope)

8m at South Pole8m at South Pole Chicago group (2008)Chicago group (2008) Large areaLarge area

• Optimized for SZ/clustersOptimized for SZ/clusters