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First results from QUIET

Osamu Tajima (KEK)The QUIET Collaboration

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B-modes have NOT been observed yet !

Direct limits : r < 0.7(ground experiment)

Indirect limits: r < 0.2

Contribution fromGravitational lensing

PrimordialB-modes

B-m

odes

pow

er

Angular Scale qLarge scale Small scaleMultipole l (=180o/q)

QUIET aims to detect B-modes from ground !

The QUIET Collaboration5 countries, 14 institutes, ~35 scientists

Chajnantor Plateau (5,080m) Chile Atacama Desert World’s best site for observation frequencies of QUIET ! 3

Observation Patches

4 CMB patches were chosen (~3% of full sky)Observing them DEEPLY (Galaxy observation when CMB patches are not visible)Map precision on 1°x1°: ~1μK (7.5 months at 43GHz) 4

~20o

CMBQUIET Telescope

Receiver( detector array inside)

CMB

5~30cm

90 detectors array for 95 GHz

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QUIET observation time at Chajnantor, 5,080m

19 detectors at 43GHz array sensitivity 69uKs1/2

90 detectors at 95GHz array sensitivity ~70uKs1/2

~30cm ~30cm

7.5 months 1.5 years

> 11,000 H

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What’s important towards B-mode detection ?

B-mode ~ 1/100 of E-modes x100 better sensitivity than past experiments• Detector array: High sensitive instrument– limitation of single detector sensitivity– Several hundreds ~ thousand detectors• several (past) ~100 (Now) ~1000 (Future)

• Good systematic error control for instrument• Understanding of Foregrounds

QUIET : intermediate stage (2008-2010) - Observation with 90 (19) detectors at 95GHz (43GHz) - One of the best B-modes search to date - Proof of technology for future

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Foregrounds and observation bands

B-mode (as QUIET-1 limits)

QUIETOther experimentsusing bolometer43 GHz 95 GHz

QUIET 43GHz data is very important to understand the contribution of Synchrotron emission

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Impact of systematic error

Have to minimize spurious polarization < 1%Have to achieve < 2o precision

Temperature anisotropy

E-modes

lensing

B-modesr = 0.10

r = 0.01

In case of 1% precision of calibrations …

spurious pol.

1% of I to Q/U2o for pol. angle

Multipole l (=180o/q)

l(l+1

)Cl /

2p (u

K2 )

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QUIET polarization detector array

CMB

Polarization

Sensor Module

Septum

Polarizer

3cm

90 detector array for 95 GHz

Array sensitivity~70 uKs1/2

Robust detector against to the systematic biases

Septum Polarizer (OMT)

x

y

Input

Output

Input

Output

L = EX+iEY

R = EX-iEY

R L

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Polarization Sensor Module

L R

+Q

-U+U

±1 1

-Q

GA GB

Septumpolarizer

HEMT amp.

Phase switch modulation at 4kHz & 50Hz

180 Coupler (±1)

90 Coupler (±i)

W-band module

Antenna to pick up “L”, “R”

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Polarization Sensor Module

L R

+Q

-U+U

±1 1

-Q

GA GB

Septumpolarizer

HEMT amp.

Phase switch modulation at 4kHz & 50Hz

180 Coupler (±1)

90 Coupler (±i)

Simultaneous measurementof Stokes Q and U

Polarization (Q, U) a GA x GB

Strong immunity from systematic biasNO spurious polarization,NO polarization angle rotation, i.e. Q/U rotation,

even though there is gain fluctuation

QUIET detector is extremely stablefor the polarization response

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I Q/U LeakageCaused by cross talk in septum polarizer　 NO time variation because it caused by waveguides components

CMB

Polarization

Sensor Module

Septum

Polarizer

DIVariation of atmosphere thickness

Elevation nods

DQSpuriouspolarization

Instrumental spurious polarization

43GHz receiver IQ : 1.0% IU : 0.2% (precision 0.1%)

average 0.6%95GHz receiver IQ : < 0.5% IU : < 0.5% ~

~

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Rotate parallactic angle withkeeping the line of sight

Q~4 min scan time for each

Q

U

θ

Calibration for Polarization (43GHz receiver)

TQ(U) cos(2(q-g)) Dgabsolute = 1.7° Catalog uncertainty

for polarization angle 1.5° at 43GHz (WMAP) 0.2° at 95GHz (IRAM)

Taurus

QUIETtelescope

Crab nebula (TauA)

by Y. Chinone

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What’s important towards B-mode detection ?

B-mode ~ 1/100 of E-modes x100 better sensitivity than past experiments• Detector array: High sensitive instrument– limitation of single detector sensitivity– Several hundreds ~ thousand detectors• several (past) ~100 (Now) ~1000 (Future)

• Good systematic error control for instrument• Understanding of Foregrounds

Robust coherent detectorCalibration, Scan strategyAnalysis method

Intermediate stage

43GHz receiver forSynchrotron emissionVerified with first results

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First results from QUIETwith 43GHz Receiver

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End-Analysis Strategy

Data Selection

Filter / Map Making

Power Spectra

Cosmological Parameters

Validation Tests

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Validation Tests

End-Analysis Strategy

Data Selection

Filter / Map Making

Blind AnalysisFramework

Power Spectra

Cosmological Parameters

Systematic ErrorCheck

Calibrations

“Box Open” Un-blinding the results - after passing validation tests - after confirmation of syst. errors

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Data Selection- way to control hidden systematic bias -

Contaminated

Clean

Data SetSele

ction

Crit

eria

Good weather

Extremely bad weather

Time-ordered-datafor polarization response

To determine the selection criteria, we need the way to evaluate such hidden bias

0.1 mK

80 mK

(S + N1) (S + N2)–

Way to evaluate the hidden bias in data without looking at the results

Analysis Validation : Null Tests

MC MC

(N1 – N2)

MC

Same CMB signal but different noise, contaminationsQU diodes diff.

We performed null tests with various subdivisions(42 different ways). - weather condition - cryostat temperature - …We determined selection criteria with feed-back from null tests 69.4% for 43 GHz detector array 21

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Evaluation of Null Spectra

Significant non-null bias(20% of statistical error)

w/ Cross-correlation w/o Cross-correlation Auto-correlation

There is significant bias even if the criteria are tighten (auto-correlation) It indicates that faint contamination was always exists in the data

Need the way to drop such effect with keeping the CMB signal

= Cl / slBias estimator :

MC w/o any contamination

Cross-correlation

Maps of different time periods

Sl + N1l

Sl + N2l

Sl + N3l

<(Sl + N1l ) (Sl + N2l )>+ <(Sl + N1l ) (Sl + N2l )>+ <(Sl + N2l ) (Sl + N3l )>

Cross-correlations with all the combinations

<Sl 2>

Technique to eliminate the noise and remaining contamination

CMB signals (Sl) are the same and correlations do not vanish, while noise terms (Nl) have no correlations <Ni

l Njl> = 0.

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There were “far-sidelobes” during 43GHz observation season

43GHzobservation

95GHzobservation

Contaminations by far-sidelobes were always existed, e.g. picking up ground structure

<-60dB ofMain beam

From Y. Chinone’s thesis.This problem was well characterized by him.

Upper part of ground screen wasmissing during 43GHz observation

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Way to divide the data towardsground structure elimination

+ 6 different deck angles

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Elimination of residual biaswith cross-correlation

Significant non-null bias(20% of statistical error)

w/ Cross-correlation w/o Cross-correlation Auto-correlation

Cross-correlation eliminates such residual bias with keeping the CMB signal

= Cl / slBias estimator :

MC w/o any contamination

There is significant bias even if the criteria are tighten (auto-correlation) It indicates that faint contamination was always exists in the data

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Results

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E-modes

Significant power is detected at 1st , 2nd peak regionConsistent with LCDM model

QUIET / LCDM = 0.87 ± 0.10PTE from LCDM 14% for EE + BB + EB

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Limits from QUIET 43GHz(7.5 months ~1/3 of BICEP-1 data)

Expected limits with 95GHz data

Expected Limits in QUIET-2w/ 500 detectors

Predictions from major models

( = 180o/q ）

B-modes : r < 2.2 @95%CL(zero-consistent : r=0.35+1.06

-0.87)

We have achieved least systematic errors to date (next page) Good prospects to achieve O(r=0.01) with upgrade

Second best upper limits wheres short observation time

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Least systematic errors to date

• Extensive study of systematic errors• Least systematic error reported to date– Strong proof of our technology for future

• Good prospects for reduction of systematic errors with 95GHz data

IQ/U leakage effect

Polarization angle uncertainty

Possible residual effectsinduced by “far-sidelobes”

They had been improved for 95GHz receiver

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Detection of Foreground

E-modes B-modes

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Foreground detection in CMB-1 patch

r = 0.02

WMAP K-band

QUIET Q-band(~1/3 of EE from LCDM)

QK cross-corr.

EEBB

One of four patches (CMB-1) at 1st bin (l=25–75)b = –3.1 for extrapolation

Consistent with synchrotron emissionIt does not dominate 95GHz region unless we reach r~0.02We confirmed “foreground receiver” at 43GHz is useful for the evaluation of foreground

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SummaryThree important items toward B-mode detection• Detector array: High sensitive instrument– Several hundreds ~ thousand detectors– QUIET demonstrates strong proof of the technology with 19

(43GHz) and 90 (95GHz) detectors• Good systematic error control for instrument– QUIET established robust analysis method– Least systematic errors to date

• To be better systematic errors with 95GHz data

• Understanding of Foregrounds– Detection of synchrotron emission at 43GHz

• one of four CMB patches• It does not dominate 95GHz region unless we reach r~0.02

– We confirmed “foreground receiver” is useful

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Another Advantage of QUIET module

No modulation

Additional modulationwith 50Hz phase switch

Moduleation with4kHz phase switch

Modulation frequencyby telescope scan

Noise spectra for 95 GHz polarimeter

1/f knee frequency << scan frequency

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Another Advantage of QUIET’s module

NO sensitivity degradation due to 1/f noise

QUIET’s sensitive regionLimited byscan range

Limited bybeam resolution

byY. Chinone

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TOD filtering• Azimuth domain filtering– Knee frequency fknee(~5.5mHz) << fscan

– Highpass cutoff around scan frequency with little loss of sensitivity

– Sufficient for both 1/f noise and atmosphere• Grand structure subtraction

Naïve N-1 filter Our filter

Scan

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Systematic Error Controlby Scan Strategy

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QUIET’s Constant Elevation Scan

Constant Elevation Constant atmosphere emissionTherefore, C.E.S minimizes the effect of atmosphere emission

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QUIET’s daily scans for the CMB-patchTrace the patch with ~20o elevation step

~1.5 hours scans at each elevation

~20o

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Natural sky rotation due to the earth rotationCMB polarization rotates with sky rotation Spurious polarization bias does not rotate !

CMB polarization

Spurious polarizationinduced by CMB temperature anisotropyand I to Q/U leakage

Leakage bias is smearedby natural sky rotation

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We smeared residual spurious polarizationwith weekly boresight rotation

Observation with various “deck” rotation

by M. Hasegawa