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First results from QUIET Osamu Tajima (KEK) The QUIET Collaboration 1.

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Presentation on theme: "First results from QUIET Osamu Tajima (KEK) The QUIET Collaboration 1."— Presentation transcript:

1 First results from QUIET Osamu Tajima (KEK) The QUIET Collaboration 1

2 B-modes have NOT been observed yet ! Direct limits : r < 0.7 (ground experiment) Indirect limits: r < 0.2 Contribution from Gravitational lensing Primordial B-modes B-modes power Angular Scale  Large scale Small scale Multipole l (=180 o /  ) QUIET aims to detect B-modes from ground ! 2

3 The QUIET Collaboration 5 countries, 14 institutes, ~35 scientists Chajnantor Plateau (5,080m) Chile Atacama Desert World’s best site for observation frequencies of QUIET ! 3

4 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 ~20 o

5 CMB QUIET Telescope Receiver ( detector array inside) CMB 5 ~30cm 90 detectors array for 95 GHz

6 QUIET observation time at Chajnantor, 5,080m 19 detectors at 43GHz array sensitivity 69uKs 1/2 90 detectors at 95GHz array sensitivity ~70uKs 1/2 ~30cm 7.5 months 1.5 years > 11,000 H 6

7 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 ( ) - Observation with 90 (19) detectors at 95GHz (43GHz) - One of the best B-modes search to date - Proof of technology for future QUIET : intermediate stage ( ) - Observation with 90 (19) detectors at 95GHz (43GHz) - One of the best B-modes search to date - Proof of technology for future 7

8 Foregrounds and observation bands B-mode (as QUIET-1 limits) QUIET Other experiments using bolometer 43 GHz 95 GHz QUIET 43GHz data is very important to understand the contribution of Synchrotron emission 8

9 Impact of systematic error Have to minimize spurious polarization < 1% Have to achieve < 2 o precision Temperature anisotropy E-modes lensing B-modes r = 0.10 r = 0.01 In case of 1% precision of calibrations … spurious pol. 1% of I to Q/U 2 o for pol. angle Multipole l (=180 o /  ) l(l+1)C l /2  (uK 2 ) 9

10 QUIET polarization detector array CMB Polarization Sensor Module Septum Polarizer 3cm 90 detector array for 95 GHz Array sensitivity ~70 uKs 1/2 Robust detector against to the systematic biases 10

11 Septum Polarizer (OMT) x y Input Output Input Output L = E X  iE Y R = E X  iE Y R L 11

12 Polarization Sensor Module L R QQ UU UU 11 11 QQ GAGA GBGB Septum polarizer HEMT amp. Phase switch modulation at 4kHz & 50Hz 180  Coupler (±1) 90  Coupler (±i) W-band module Antenna to pick up “L”, “R” 12

13 Polarization Sensor Module L R QQ UU UU 11 11 QQ GAGA GBGB Septum polarizer HEMT amp. Phase switch modulation at 4kHz & 50Hz 180  Coupler (±1) 90  Coupler (±i) Simultaneous measurement of Stokes Q and U Polarization (Q, U)  G A x G B Strong immunity from systematic bias NO spurious polarization, NO polarization angle rotation, i.e. Q/U rotation, even though there is gain fluctuation QUIET detector is extremely stable for the polarization response 13

14 I  Q/U Leakage Caused by cross talk in septum polarizer NO time variation because it caused by waveguides components CMB Polarization Sensor Module Septum Polarizer II Variation of atmosphere thickness Elevation nods QQ Spurious polarization Instrumental spurious polarization 43GHz receiver I  Q : 1.0% I  U : 0.2% (precision 0.1%) average 0.6% 95GHz receiver I  Q : < 0.5% I  U : < 0.5% ~~~~ 14

15 Rotate parallactic angle with keeping the line of sight Q ~4 min scan time for each Q U θ Calibration for Polarization (43GHz receiver) T Q(U) cos(2(  -  ))  absolute = 1.7° Catalog uncertainty for polarization angle 1.5° at 43GHz (WMAP) 0.2° at 95GHz (IRAM) Taurus QUIET telescope Crab nebula (TauA) by Y. Chinone 15

16 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 detector Calibration, Scan strategy Analysis method Intermediate stage 43GHz receiver for Synchrotron emission Verified with first results 16

17 First results from QUIET with 43GHz Receiver 17

18 End-Analysis Strategy Data Selection Filter / Map Making Power Spectra Cosmological Parameters Validation Tests 18

19 Validation Tests End-Analysis Strategy Data Selection Filter / Map Making Blind Analysis Framework Power Spectra Cosmological Parameters Systematic Error Check Calibrations “Box Open” Un-blinding the results - after passing validation tests - after confirmation of syst. errors 19

20 Data Selection - way to control hidden systematic bias - Contaminated Clean Data Set Selection Criteria Good weather Extremely bad weather Time-ordered-data for polarization response To determine the selection criteria, we need the way to evaluate such hidden bias 0.1 mK 80 mK 20

21 (S + N 1 ) (S + N 2 ) – Way to evaluate the hidden bias in data without looking at the results Analysis Validation : Null Tests MC (N 1 – N 2 ) MC Same CMB signal but different noise, contaminations Q  U 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

22 Evaluation of Null Spectra 22 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 = C l /  l Bias estimator :  MC w/o any contamination

23 Cross-correlation Maps of different time periods S l + N 1 l S l + N 2 l S l + N 3 l + Cross-correlations with all the combinations  Technique to eliminate the noise and remaining contamination CMB signals (S l ) are the same and correlations do not vanish, while noise terms (N l ) have no correlations  = 0. 23

24 There were “far-sidelobes” during 43GHz observation season 43GHz observation 95GHz observation Contaminations by far-sidelobes were always existed, e.g. picking up ground structure <-60dB of Main beam From Y. Chinone’s thesis. This problem was well characterized by him. 24 Upper part of ground screen was missing during 43GHz observation

25 Way to divide the data towards ground structure elimination different deck angles

26 Elimination of residual bias with cross-correlation 26 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 = C l /  l Bias 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

27 Results 27

28 E-modes 28 Significant power is detected at 1 st, 2 nd peak region Consistent with  CDM model QUIET / LCDM = 0.87 ± 0.10 PTE from LCDM 14% for EE + BB + EB

29 Limits from QUIET 43GHz (7.5 months ~1/3 of BICEP-1 data) Expected limits with 95GHz data Expected Limits in QUIET-2 w/ 500 detectors Predictions from major models ( = 180 o /  ) B-modes : r < (zero-consistent : r= ) 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 29

30 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 I  Q/U leakage effect Polarization angle uncertainty Possible residual effects induced by “far-sidelobes” They had been improved for 95GHz receiver 30

31 Detection of Foreground E-modes B-modes 31

32 Foreground detection in CMB-1 patch r = 0.02 WMAP K-band QUIET Q-band (~1/3 of EE from  CDM) Q  K cross-corr. EE BB One of four patches (CMB-1) at 1 st bin ( l =25–75)  = –3.1 for extrapolation Consistent with synchrotron emission It does not dominate 95GHz region unless we reach r~0.02 We confirmed “foreground receiver” at 43GHz is useful for the evaluation of foreground 32

33 Summary Three 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 33

34 34

35 Another Advantage of QUIET module No modulation Additional modulation with 50Hz phase switch Moduleation with 4kHz phase switch Modulation frequency by telescope scan Noise spectra for 95 GHz polarimeter 1/f knee frequency << scan frequency 35

36 Another Advantage of QUIET’s module NO sensitivity degradation due to 1/f noise QUIET’s sensitive region Limited by scan range Limited by beam resolution by Y. Chinone 36

37 TOD filtering Azimuth domain filtering – Knee frequency f knee (~5.5mHz) << f scan – Highpass cutoff around scan frequency with little loss of sensitivity – Sufficient for both 1/f noise and atmosphere Grand structure subtraction Naïve N -1 filterOur filter Scan 37

38 Systematic Error Control by Scan Strategy 38

39 QUIET’s Constant Elevation Scan Constant Elevation  Constant atmosphere emission Therefore, C.E.S minimizes the effect of atmosphere emission 39

40 QUIET’s daily scans for the CMB-patch Trace the patch with ~20 o elevation step ~1.5 hours scans at each elevation 40 ~20 o

41 Natural sky rotation due to the earth rotation CMB polarization rotates with sky rotation Spurious polarization bias does not rotate ! CMB polarization Spurious polarization induced by CMB temperature anisotropy and I to Q/U leakage Leakage bias is smeared by natural sky rotation 41

42 We smeared residual spurious polarization with weekly boresight rotation Observation with various “deck” rotation by M. Hasegawa 42


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