QUIETQ/U Imaging ExperimenT

Osamu Tajima (KEK)QUIET collaboration 1

Age 　　　 10-36 sec 　　　　 380 Kyr 　　　　 1 Myr 　　　　　　　　　　　　 13.8 Gyr

Inflation

reconbinationDark age

Begin of universe

reionization

Big bang

CMB First starForegronds Today

Galaxies

History of The Universe

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Standard cosmology model？

Inflationpotential × 1016 GeVV1/4 ≈ 0.01

1/4 r

Parameterized with “ r “ : tensor-scalar ratio (T/S)

Energy scale of inflation

StandardModel

？Grand Unified Theory

GUT scale 1016 GeV

Planck scale

Happen to be

same order !?

Targets of QUIET

Model predictions of B-modes from the inflation

E-modes

l(l+1

)Cl /

2p (u

K2 )

Lensing B-modes

Primordial B-modes“Inflationary B-modes”

QUIET0.2°〜 7°

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Wide multipole range should be coveredfor ``Inflationary B-modes’’

Toward Inflationary B modes

• Good systematic error control– Inflationary BB power is less than 1/1,000,000 of TT,

1/10~1/100 or less of EE– Understanding of Foregrounds– Mitigation of experimental systematics

• Large fields observation– Inflationary BB is significant more than 1o scale– Should be free from experimental 1/f noise

QUIET is designed to fulfill these requirements4

The QUIET Collaboration5 countries, 14 institutes, ~50 scientists

QUIET observation: Oct. 2008 – Dec. 2010 at Atacama, Chile (5,080m) 5

Observation Patches

4 CMB patches were chosen (~3% of full sky)Galaxy observation when CMB patches are not visible

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~20o

Visible region along earth rotation

QUIET (43 GHz)

WMAP(5-year)

Stokes, Q Stokes, U

Thus far useful for demonstration

CMBQUIET Telescope

Receiver( detector array inside)

CMB

7~30cm

QUIET polarization module90 sets for 95 GHz observation

Constraint on Foregrounds with multi-frequency observations

QUIET

Other experiments43 GHz 95 GHz

QUIET’s 43GHz data is important to understand effects of Synchrotron radiations

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QUIET observation at Atacama, Chile 5,080m

19 detectors at 43 GHz array sensitivity 69uKs1/2

90 detectors at 95 GHz array sensitivity ~87uKs1/2

~30cm ~30cm

~8 months ~1.5 years

> 11,000 H

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QUIET polarization detector array

CMB

Circuit module

Septum

Polarizer

3cm

Detector array for 95 GHz

Essence of tiny 1/f knee & good systematic error control

10Yield of usable detectors: 95%

DoubleMod.

QUIET’s detector

L R

D1

D3D2

±1 ±1

D4

Septumpolarizer

LNA (HEMT)

Phase switch phase flip modulation ( 4kHz & 50Hz )

180 Coupler (±1)

90 Coupler (±i)

W-band module

Antenna to pick up “L”, “R”

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CMB

DoubleMod.

D1

D3D2

D4+Q

-U+U

-Q

Phase switch phase flip modulation ( 4kHz & 50Hz )

QUIET’s detector

L R

±1 ±1

gA gB

Septumpolarizer

LNA (HEMT)

180 Coupler (±1)

90 Coupler (±i)

Simultaneous detection of Stokes Q and U！

Tiny spurious polarization Imperfection of waveguide components makes tiny fake-pol. However, it doesn’t fluctuate, i.e., could be calibrated very well

Precise polarization angle f = ½ tan-1(U/Q) ½ tan-1(D3/D1)

Stable ! No fluctuation !!

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CMB

D1 = + gA gB × QD2 = - gA gB × UD3 = + gA gB × UD4 = - gA gB × Q

Each diode response

gA , gB Responsivity of LNA

Very small 1/f knee

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Observing dataunder Chilean sky

fknee << fscan

Double demodulation suppressed 1/f noise !!

Very small 1/f knee

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Scan freq.

Noise property of experiment

E-modes

B-modes

Measurement range

QUIET is free from effects of 1/f noise !!

Tiny spurious polarization

Median of all channels (95 GHz band): 0.2% ±0.2% (syst. error dominant)

Calibration was scheduled every a few hours(~0.3% precision for each)

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q

Total power response as a function of time

We also performed cross calibration by using astronomical objects, e.g., Jupiter

DI

Elevation nods

DQ

Angle calibration: TauA x sparse-wires(cross check for relative)Absolute Relative (cross check for absolute)

dangle: 0.5deg (catalog uncertainty is 0.2deg) 16

Q

U

Taurus

Tpol. = 5mK, αsky=149.9±0.2° Orientation of sinusoidal curve determines detector angle

Yellow bar: precision of single calibration

Measured angle of ``standard detectors’’calibration everyday unless it was invisible

No angle fluctuation !!

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(cross check for relative)Absolute Relative (cross check for absolute)

Angle calibration: TauA x sparse-wiresArtificial calibrator, ``sparse wires’’ determined relative angles

Systematic error for relative angle: 0.8o

Analysis Strategy

Calibration, Data Selection

Filter / Map Making

B-mode, E-mode spectra

Validation Tests

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Stokes Q map Stokes U map

Multipole l (=180o/q)

E-modes

B-modes

This is simulation This is simulation

This is simulation

Blind AnalysisFramework

Validation Tests

Analysis Strategy

Calibration, Data Selection

Filter / Map Making

B-mode, E-mode spectra

Systematic ErrorCheck

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“Robust”

✓✓

“Box Open” Un-blinding the results

Analysis Validation: Null Tests• Divide data set into two maps, difference them.

• Calculate “null” power spectrum• Perform 42 data divisions for 43 GHz

(32 divisions for 95 GHz receiver)– Q vs. U channels– weather conditions– cryostat temperature

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(CMB+NoiseA) - (CMB+NoiseB) (NoiseA-NoiseB)

Null Power Spectrum

Passed null tests ? YES !

No bias was detected !– Zero-consistent mean shift +0.02 ±0.02 (-0.02±0.02) for 43 GHz (95 GHz)– Distribution is consistent with MC validation of statistical error

●　 dataー MC w/o any systematics

Bias estimator : = Cl / sl 43 GHz band receiverMean shifts bias detection

Width statistical error validation

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``Far-sidelobes’’ induced ground pickup

43 GHz observation 95 GHz observation

UGS solves Far-sidelobes

Characterized by using the

Sun

43 GHz receiver

95 GHz receiver

One of the source of detected bias by the validation tests

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Remove effects of ground pickupby far-sidelobes

x 6 different angles

Take cross-correlation10 divisions for Azimuth

X6 divisions of boresight rotations

Motion of each patch

QUIET’s E-modes

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Two independent analysis pipeline obtained consistent results. (Calibrations are not common partially)

43 GHz band receiver95 GHz band receiver

QUIET’s B-modes

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43 GHz band receiver95 GHz band receiver

Zero-consistent power observed

Upper limit for B-modes

Upper bounds at 95% C.L. 43 GHz band: r < 2.2 95 GHz band: r < 2.7 26

Systematic error for B modes

The smallest syst. error to date: δr<0.01Major inflation models could be covered with large statistics

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Real data shows “Foreground receiver” is important !!Good estimator for effects of Synchrotron radiation 28

WMAP 30GHz

QUIET 43GHz(~1/3 of EE from LCDM)

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

Foreground receiver did its task

r = 0.02

F.G. for E-modes

F.G. forB-modes

QUIET(43GHz)WMAP(30GHz) cross-correlation

QUIET 95GHz

Summary• QUIET’s target: B-modes from the inflation

– Designed to minimize systematics• Having Foreground receiver• Very good systematic error control

– Very low 1/f noise• First experiment Japanese institution joined• One of the best CMB polarization spectrum

measurements to date. – In particular E modes “spectrum”– The lowest systematic error to date: dr < 0.01

• Published papers• Results with 43 GHz receiver: ApJ, 741, 111 (2011).• Results with 95 GHz receiver: ApJ, 760, 145 (2013).• About Instruments: ApJ, 768, 9 (2013). 29

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Referee report for 95 GHz receiver resultsLet me congratulate the QUIET team for this impressive piece of work! The control of all systematics down to r of 0.01 is absolutely spectacular. I found the paper clearly written, and a model for future polarization based CMB papers…