High Resolution Measurements of CMB Anisotropies with ACBAR

U.C. Berkeley:W.L. Holzapfel (co-PI)M.D. DaubM. LuekerCase-Western:J. Ruhl (co-PI)J. GoldsteinJPL/Caltech:J.J. BockC.L. KuoA.E. LangeC. Reichardt

CMU:J.B. PetersonSussex:A.K. RomerL. ValkonenCardiff:P.A. AdeAround the WorldM.C. Runyan

ACBAR is funded by the NSF Office of Polar Programs

ACBAR Collaborators

ACBAR was built to:

(Gomez et al. 2003)

Measure the CMB temperature anisotropies

Search for new SZ clusters

Make targeted multi- SZ

observations of clusters.

(White, Hernquist, & Springel 2002)

ACBAR’scoverage

WMAP

CMB Power Spectrum• CMB physics is well-understood

and calculable (linear regime: cdm~10-3)

• Experiments measure exactly what theory predicts!

• What is the universe made of?• What drives its dynamics? • How did structure form?

(C. Lineweaver, 2003)

Plasma falling into a dark matter overdensity

The Damping TailPhoton diffuse out of over-dense regions & carry baryons with them. The acoustic oscillator has a Q~5.The damping scale measures theangular scale of Silk length at recombination: Silk length ~ 3.5 Mpc (m/ b)1/2 (mh2)-3/4

An independent measure of cosmological parameters

•Break degeneracies•Test for new physics

(W. Hu, 2002)

ACBAR:

Instrument and Observations

Winterover

Special Thanks to our Crazy Winter-overs

Helium fill:Winter 2002

Matt Newcomb, 2001 & 2002

Justus Brevik 2004

Jessica Dempsey2005

Cooled to 230mKHe3/He3/He4Fridge

24-hour hold time

Arcminute Cosmology Bolometer Array Receiver

4K

350mK

230mK

FET

120K

JPL MDL Bolometers

16-element arrayCorrugated feed horns

Picture and bolometer provided by JPL Microdevices Lab ACBAR Bolometers

•Fast (~3 ms)

•Broadband

•Very sensitive

Map 1 deg2 to 10 K per beam at 150 GHz in ~3h.

# Band

(GHz)

TRJ

(K)

NETCMB

(Ks)

8x(added 2005)

150 34 330

8x 150 39 345

The Viper TelescopeSchematic diagram of the optics (2m off-axis Gregorian)

Triangular wave 0.3 Hz, 3ºpeak to peak

Large Chop (~3˚)+ small beams = wide -range

Ground shield blocks emission from EL < 25˚

Optimizing the Analysis

CMB5 FieldWinter 2002

CMB5 field, M-(L+T)/2

CMB5, un-differenced

Cosmic Variance:3x area

Noise:S/N improves by 8/3

No-LMTScan with nearly constant elevation

CalibrationQuickTime™ and a

TIFF (LZW) decompressorare needed to see this picture.

CMB DipoleWMAP

Boomerang

ACBAR

Galactic sources mapped multiple times per day.

Used to construct

pointing model and calibration

Raster map of RCW38

B03 observed RCW38 at 150

GHz too!

6% calibrationin temperature

Foregrounds

Avoids foregrounds:• Dust• Radio sources

Plenty of low-dust sky available year-round

Radio sources: cmb5

Sources in the PMN radio source catalogue are removed in the PS analysis.

Monitor beam size and pointing with mm-bright point sources in each field.

Black: ACBAR new analysisRed: ACBAR 2002 releaseRed: ACBAR 2002 releaseGreen: CBIGreen: CBI

No-LMT Power Spectrum – preview•New analysis method (no-LMT)•Improved calibration •2x more sky

More to come from ACBAR!

2004: 5 months of observationInstrument unchanged from 2002

2005: Full winter of observationReconfigured the focal plane to double the number of detectors at 150 GHz

6.5x More Sky&

3.7x More Time!ACBAR B03

Improved Calibration

Portion of B03 Deep Field

Full ACBAR Dataset

• Measure the higher acoustic peaks and damping tail of the power spectrum with high signal-to-noise

• Improve calibration by factor of 2-3 – Even better with

WMAP 4th year!

Improve estimates of m, b, ns, dns/dlnk …

QuickTime™ and aTIFF (LZW) decompressor

are needed to see this picture.

Hu, 2001, ApJL

Lensing probes the large scale matter distributionusing smaller objects with known (average) shape

The growth of large scale structure depends critically on dark energy

Challenge: CMB is a gaussian random field w/o fixed shape

Unlensed Lensed

ACBAR’s deep fieldsshould have 2-3 sigma detection.

Really Massive Source

Lensing

CBI’s High- Excess

•Point Sources–Radio sources–dusty galaxies

•Non-standard Inflation

•SZE

355 103 K2 at 30 GHz

Cooray & Melchiorri, 2002astro-ph/0204250

Predictions: Non-standard inflation: power equal at 150 GHzSZ excess: power reduced by ~4 at 150 GHz

QuickTime™ and aTIFF (LZW) decompressor

are needed to see this picture.

High- Excess?

SZ results in a ratio 4 for the observed powers.

• Looking good: SZE from clusters, SZE from pop. III stars..

• NOT looking good: primordial magnetic fields, primordial voids…

SZ

Primordial…CBI

BIMA

ACBAR

Goldstein et al. astro-ph/0212517

Dawson et al.

LMT Analysis: consistent with either

Reanalysis (no-lmt) of 2002 Data

Summary

• ACBAR has measured CMB temperature anisotropies with high S/N to > 2000– Paper coming out soon

• Analysis is underway to:– Calibrate with CMB anisotropies to WMAP and B03– Improved power spectrum measurement by including nearly

4x more data and 7x more sky from last winter.

– Detect Gravitational Lensing

– SZ clusters• Pointed Observations• Blind search for unknown clusters

The End