1. GWDAW-8 (December 17-20, 2003, Milwaukee, Wisconsin, USA) Search for burst gravitational waves with TAMA data Masaki Ando Department of Physics, University of Tokyo TAMA Collaboration Burst wave analysis with TAMA data Excess power filter Veto: signal behavior auxiliary channel Event candidate list Evaluation of the list Overview

2. GWDAW-8 (December 17-20, 2003, Milwaukee, Wisconsin, USA) 2 Contents Introduction Analysis targets and data Burst wave filter Excess power filter Parameter selection Non-Gaussian noise reduction Time-scale selection Software injection test, Threshold setting Veto analysis with auxiliary channel Correlation check Estimation of accidentals, Threshold setting Hardware injection test Event list investigation Summary

3. GWDAW-8 (December 17-20, 2003, Milwaukee, Wisconsin, USA) 3 Contents Introduction Analysis targets and data Burst wave filter Excess power filter Parameter selection Non-Gaussian noise reduction Time-scale selection Software injection test, Threshold setting Veto analysis with auxiliary channel Correlation check Estimation of accidentals, Threshold setting Hardware injection test Event list investigation Summary

4. GWDAW-8 (December 17-20, 2003, Milwaukee, Wisconsin, USA) 4 Introduction (1) - Targets - Targets ： Burst waves from Supernovae Numerical simulation … ~100 waveforms are predicted Not cover all initial conditions H.Dimmelmeier et al, Astron. Astrophys. 393 (2002) 523. T. Zwerger, E. Müller, Astronomy & Astrophysics, 320 (1997), 209. Common characteristics : Short burst waves Spike wave ~1msec Duration time <30msec Not suitable for templates (matched filtering: not available)

5. GWDAW-8 (December 17-20, 2003, Milwaukee, Wisconsin, USA) 5 Introduction (2) - Data from TAMA300 - Data TakingObjective Observation time Typical strain noise level Total data (Longest lock) DT1August, 1999Calibration test1 night3x10 -19 /Hz 1/2 10 hours (7.7 hours) DT2 September, 1999 First Observation run3 nights3x10 -20 /Hz 1/2 31 hours DT3April, 2000 Observation with improved sensitivity 3 nights1x10 -20 /Hz 1/2 13 hours DT4 Aug.-Sept., 2000 100 hours' observation data 2 weeks (night-time operation) 1x10 -20 /Hz 1/2 (typical) 167 hours (12.8 hours) DT5March, 2001 100 hours' observation with high duty cycle 1 week (whole-day operation) 1.7x10 -20 /Hz 1/2 (LF improvement) 111 hours DT6 Aug.-Sept., 2001 1000 hours' observation data 50 days5x10 -21 /Hz 1/2 1038 hours (22.0 hours) DT7 Aug.-Sept., 2002 Full operation with Power recycling 2 days25 hours DT8 Feb.-April., 2003 1000 hours Coincidence 2 months3x10 -21 /Hz 1/2 1157 hours (20.5 hours) DT9 Nov. 2003 - Jan., 2004 Automatic operation Night-time and week ends 1.5x10 -21 /Hz 1/2 ---

6. GWDAW-8 (December 17-20, 2003, Milwaukee, Wisconsin, USA) 6 Introduction (3) - Data Taking 8 - Data Taking 8 Feb.14 – April 14, 2003 (2-month observation, 94 shift members) Obs. time : 1157 hours Duty Cycle : 81% Typical Noise level DT6: 7x10 -21 /Hz 1/2 @ 800Hz DT8: 3x10 -21 /Hz 1/2 @1.3kHz DT9: 2x10 -21 /Hz 1/2 @ 900Hz

7. GWDAW-8 (December 17-20, 2003, Milwaukee, Wisconsin, USA) 7 Contents Introduction Analysis targets and data Burst wave filter Excess power filter Parameter selection Non-Gaussian noise reduction Time-scale selection Software injection test, Threshold setting Veto analysis with auxiliary channel Correlation check Estimation of accidentals, Threshold setting Hardware injection test Event list investigation Summary

8. GWDAW-8 (December 17-20, 2003, Milwaukee, Wisconsin, USA) 8 Time- Frequency plane (spectrogram) Excess power filter Burst-wave analysis (1) - Excess power filter - Raw Data (time series) Total power in given T-F region Few assumptions for signal … time-frequency bands Robust for waveform uncertainties Signal !! Evaluate signal power in given time-freqency regions Spectrogram Freq. sum

9. GWDAW-8 (December 17-20, 2003, Milwaukee, Wisconsin, USA) 9  t = 200 [msec]  f = 500 [Hz] Burst-wave analysis (2) - Parameter selection - Parameter selection : duration time, frequency band Target : Burst waves Short duration time, wide frequency band (c.f. cont. waves: long duration, narrow freq. band) For better SNR … Shorter time window Lower freq. Resolution (affects by line peaks) Wider freq. band Degraded noise level

10. GWDAW-8 (December 17-20, 2003, Milwaukee, Wisconsin, USA) 10 Burst-wave analysis (3) - Excess power outputs - DT8 time series Excess power filter outputs Noise level drift Large outliers in daytime Noise reduction is required

11. GWDAW-8 (December 17-20, 2003, Milwaukee, Wisconsin, USA) 11 Contents Introduction Analysis targets and data Burst wave filter Excess power filter Parameter selection Non-Gaussian noise reduction Time-scale selection Software injection test, Threshold setting Veto analysis with auxiliary channel Correlation check Estimation of accidentals, Threshold setting Hardware injection test Event list investigation Summary

12. GWDAW-8 (December 17-20, 2003, Milwaukee, Wisconsin, USA) 12 Non-Gaussian noise reduction (1) - Reduction principle - Reduction of non-Gaussian noise noises Time-scale selection of events candidates Real GW bursts < 30 msec Fake events > a few sec 2 statistics Averaged power 2 nd -order moment C2C2 C1C1 Theoretical curve For short bursts c 1 -c 2 Correlation plot Time scale of event candidates short long Distance to theoretical curve (D) : ‘likelihood’ to be GW

13. GWDAW-8 (December 17-20, 2003, Milwaukee, Wisconsin, USA) 13 Non-Gaussian noise reduction (2) - Parameter and threshold - Parameter selection: average time and threshold Average time window Should be long enough for statistical significance Should be same order as fake events  T = 3.2 [sec] Threshold for selection : D th Rejection efficiency depends on the noise behavior Software injection test with real data D th = 5, F.D. : 4% (theory : F.D. < 1ppm)

14. GWDAW-8 (December 17-20, 2003, Milwaukee, Wisconsin, USA) 14 Non-Gaussian noise reduction (3) - Reduction results - DT8 time series Excess power filter Time scale selection D th = 5 (F.D: 4%) Rejected most of the large-amplitude events Lost little obs. time (~0.4%) Obs. data After rejection (D th ＝ 20) After rejection (D th ＝ 5)

15. GWDAW-8 (December 17-20, 2003, Milwaukee, Wisconsin, USA) 15 Contents Introduction Analysis targets and data Burst wave filter Excess power filter Parameter selection Non-Gaussian noise reduction Time-scale selection Software injection test, Threshold setting Veto analysis with auxiliary channel Correlation check Estimation of accidentals, Threshold setting Hardware injection test Event list investigation Summary

16. GWDAW-8 (December 17-20, 2003, Milwaukee, Wisconsin, USA) 16 Veto analysis (1) - Raw data around an event candidate - DT8, one of the largest events ( h rms = 6x10 -16 ) Spectrum Raw data Averaged noise level Spectrum around the event Intensity monitor data for the same time Clear correlation No correlation In the other channels

17. GWDAW-8 (December 17-20, 2003, Milwaukee, Wisconsin, USA) 17 Veto analysis (2) - Correlation analysis - Event investigation (100 hours’ data) 114 events with h >2.2x10 -20 [1/Hz 1/2 ] Excess power filter analysis for intensity monitor data (15-500Hz) Clear correlation in most cases 250msec time shift no correlation

18. GWDAW-8 (December 17-20, 2003, Milwaukee, Wisconsin, USA) 18 Veto analysis (3) - Accidental coincidence and threshold - Veto with intensity monitor Accidental coincidence rate Evaluated by time shifts Averaged rate of int. excess 25 sec around events Threshold : P n =1.4 accidental coincidence: 1% (F.D =1%)

19. GWDAW-8 (December 17-20, 2003, Milwaukee, Wisconsin, USA) 19 Veto analysis (4) - Signal injection experiment - Hardware injection test Carried out during DT8 (ZM signal, Delta function signal) 185 injections Did not appear in the intensity channel Confirmed that ‘real GW signal would not appear in the intensity monitor channel’

20. GWDAW-8 (December 17-20, 2003, Milwaukee, Wisconsin, USA) 20 Contents Introduction Analysis targets and data Burst wave filter Excess power filter Parameter selection Non-Gaussian noise reduction Time-scale selection Software injection test, Threshold setting Veto analysis with auxiliary channel Correlation check Estimation of accidentals, Threshold setting Hardware injection test Event list investigation Summary

21. GWDAW-8 (December 17-20, 2003, Milwaukee, Wisconsin, USA) 21 Event candidates (1) - Event rate - Event rate h rms : 3x10 -17 (1msec spike) 0.8 events/hour (1/50 reduction with F.D. ~5%) Much larger rate than Simulated results with Gaussian noise Too large for real signal (Our galaxy will disappear in 10 6 years) Fake events by detector noise 3x10 -17

22. GWDAW-8 (December 17-20, 2003, Milwaukee, Wisconsin, USA) 22 Event candidates (2) - Time dependence - Time dependence of event rate No time dependence (Solar time, sidereal time) Intrinsic noise of the detector

23. GWDAW-8 (December 17-20, 2003, Milwaukee, Wisconsin, USA) 23 Summary Burst GW analysis with TAMA data 2000 hours data (DT6, DT8) Excess power filter, Time-scale selection, Veto (intensity) Event rate : 0.8 events/hour (1msec, h rms > 3x10 -17 burst waves) Too large event rate Origin: detector instability Current tasks Efficiency test, optimization (preparation for coincidence) Event list exchange (DT6  ROG, DT8  LIGO) TAMA detector improvement (detector characterization)

24. GWDAW-8 (December 17-20, 2003, Milwaukee, Wisconsin, USA) 24 End