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Experimental results correlating GW detector data and Gamma Ray Bursts

Experimental results correlating GW detector data and Gamma Ray Bursts. Giuseppina Modestino LNF. ROG Collaboration INFN – LN Frascati, LN Gran Sasso, Sez . Roma 1, Roma 2 and Genova Universities “La Sapienza” and “Tor Vergata” Rome, L’Aquila, Geneve CNR – IFN Roma

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Experimental results correlating GW detector data and Gamma Ray Bursts

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  1. Experimental results correlating GW detector data and Gamma Ray Bursts Giuseppina Modestino LNF ROG Collaboration INFN – LN Frascati, LN Gran Sasso, Sez. Roma 1, Roma 2 and Genova Universities“La Sapienza” and “Tor Vergata” Rome, L’Aquila, Geneve CNR –IFN Roma INAF –IFSI Roma CERN - Geneve oct 2006 g.modestino

  2. Summary • Search for GW Burst Signals and resonant cryogenic detectors. • GW and GRB associationEXPERIMENTAL IMPLICATIONS. • Data analysis under two hypotheses • COSMIC RAYS DETECTION • analogies and calibration • Experimental results • Previous and in progress oct 2006 g.modestino

  3. Search for GW Burst Signal GW Burst Sources • Binary system coalescence • Supernovae • ms pulsars SNR ~ 103 (10kpc/d)2 (10-44Hz-1/h2) (Df /1Hz) d = distance from earth h = detector spectral density Df = bandwidth of detection oct 2006 g.modestino

  4. Search for GW Burst Signal Cryogenic resonant detectors GW detection sensitivity • ALLEGRO • AURIGA • EXPLORER • NAUTILUS h = 10-21 ÷ 10-20 Hz-1/2 Df = 1 ÷ 50 Hz SNR ≥ 10 for a galactic event oct 2006 g.modestino

  5. Search for GW Burst Signal Initial operation of the International Gravitational Event Collaboration G.A. Prodi et al. (IGEC Collaboration) Int. Jour. of Modern Physics D 9, 237 (2000) Study of coincidences between resonant gravitational wave detectors P. Astone et al. (ROG Collaboration) Class. Quantum Grav. 18, 243–251 (2001) First search for gravitational wave bursts with a network of detectors Z.A. Allen et al. (IGEC Collaboration) Phys. Rev. Lett. 85, 5046-5050 (2001) Search for gravitational wave bursts by the network of resonant detectors P. Astone et al. (IGEC Collaboration) Class. Quantum Grav. 19, 1367–1375 (2002) Study of the coincidences between the gravitational wave detectors EXPLORER and NAUTILUS in 2001 P. Astone et al. (ROG Collaboration) Class. Quantum Grav. 19, 5449–5463 (2002) Methods and results of the IGEC search for burst gravitational waves in the years 1997–2000 P. Astone et al. (IGEC Collaboration) Phys. Rev. D 68, 022001 2003 oct 2006 g.modestino

  6. Typical theoretical prediction for GW burst amplitude: Dl/l = h = 3 10-20 1kHz1Mpc (MGW/10-2 Mo)1/2 (10-3s/tGW)1/2 f(kHz)R(Mpc) associated to a single GRB event: @ 1 kHz tGW = 1ms 10-22 (MGW)1/2 R(Gpc) Gravitational wave luminosity [1055erg/s] Ruffert et al.,AA 311,532 (1996) 2. h~ 1. 0. 2 4 6 Time [ms] oct 2006 g.modestino

  7. Data Analysis GW Burst Detection Strategy • List of candidate events obtained selecting • (with an adaptive threshold) data produced by • filter matched to a delta • Search for coincidences Experimental Tools Statistical excess Local mass distribution for the directional studies + time reference Statistical association Link with GRBs (GRB=systematic phenomenon) oct 2006 g.modestino

  8. ASSOCIATION WITH SUPERNOVAE • Measurements with the resonant Gravitational Wave • detector EXPLORER during the GRB 980425 • No anomaly in the background of the GW data • detector with the sensitivity of h>=10-18 • (ROG Coll.)Astron. Astrophys. Suppl. Ser. 138 605-606 1999 • Search for GW associated with the GRB030329 using the • LIGO detector. • None candidate event detected in the signal time region • of 180s [ -120s, + 60s ] around t • (LIGO Coll.)Phys.Rev. D 72, 042002 (2005) oct 2006 g.modestino

  9. Experimental studies: Statistical association • Search for Time Correlation Between GRBs nd Data from the • Gravitational Wave Antenna EXPLORER. • Coincidence technique. • No evidence in a time window of + 1 s , at several delays. • (ROG Coll.)Astron. Astrophys. Suppl. Ser. 138, 603 –604 (1999) • Correlation between GRBs AND GWs. • Using 120 GRBs, in a 10s time window, an U.L. of 1.5 10-18 was obtained. • (AURIGA Group)Phys.Rev. D 63, 082002 (2001) • Search for Correlation between GRBs detected y BeppoSax and • gravitational wave detectors EXPLORER AND NAUTILUS • Cross-correlation technique- • Absence of signal of amplitudeh>1.2 10-18 within + 400 s. • (ROG Coll. )Phys. Rev. D 66, 102002 (2002) h>6.5 10-19 + 5 s. • Cumulative analysis of the association between the data of the GW detectors NAUTILUS and EXPLORER and GRBs detected by BATSE and BeppoSAX. • Analysis of the data relative to a large number of GRBs detected during • the ‘90s, allows to exclude GW burst signal with h> 2.5 10-19 • (ROG Coll. )Phys. Rev. D 71, 042001 (2005) oct 2006 g.modestino

  10. Zero-threshold search:better sensitivity than the "event" method for the expected "small" signals. 1)Combine the GW detector data E(t) with the same relative time with respect to the N GRB arrival time t0 For the single data stretches si = <Ei> E1 E2 2)Applying a cumulative algorithm:s = si N-1/2 E3 En Dt(s) t=tGRB oct 2006 g.modestino

  11. Cosmic Ray detectors EXPLORER is equipped with 3 layers of Plastic Scintillators 2 above the cryostat - area 13m2 1 below -area 6 m2) NAUTILUS is equipped with 7 layers of Streamer tubes 3 above the cryostat - area 36m2/each 4 below -area 16.5 m2/each) Studing the effects of the showers on the crygenic bars oct 2006 g.modestino

  12. The effect of the Cosmic Ray Shower on NAUTILUS A true mechanical pulse Unfiltered signal (V2) The signal after filtering (kelvin) The cosmic ray effect on the bar is measured by an offline correlation, driven by the arrival time of the cosmic rays, between the observed multiplicity in the CR detector and the data of the antenna, processed by a filter matched to  signals oct 2006 g.modestino

  13. The effects of th CR on resonant GW detectors Thermo-acoustic model oct 2006 g.modestino

  14. Zero-threshold search Cosmic-ray showers interacting with NAUTILUS 2000 kelvin 2001 <E(t)>= 3 10-3K s ~ 10-4 K DE ~ 3. 10-4 kelvin Time [s] Astone et al. (ROG Coll.) PRD, 84, 14, 2000. Astone et al. (ROG Coll.) Phy. Lett. B 499 16 (2001) Astone et al. (ROG Coll.) Phys. Lett. B 540 179 (2002) In agreement with the thermo-acoustic model oct 2006 g.modestino

  15. Time delay between the two emissions The typical amplitude of a GW burst, on Earth, associated to a single GRB, is: R = distance M = amount of GW energy emitted (Mo) 10-22 M1/2 R(Gpc) h = But there is no clear predictions about Dt=|tGRB-tGW| It implies an intrinsic difficulty relating the upper limit on the amplitude, in general, interpreting the measurement results. By experiment, it is possible to solve the problem, correlating the data of 2 GW detectors Essentially, two methodologies are possible: Coincidence analysis Cross-correlation technique (advised in nonstationary noise conditions) oct 2006 g.modestino

  16. Searching for GW signals under variable delay hypothesis The basic idea of the analysis is the simultaneity of the signal on two GW detectors. • Apply the usual data selection criteria evaluating the temperature noise in the time interval around the GRB time • Select and cross-correlate data of the coincident intervals of the two GW detectors. • Apply the usual cumulative algorithm to the cross-correlation function Phys. Rev. D 65 022005 (2002) Phys. Rev. D 66 102002 (2002) oct 2006 g.modestino

  17. Search for GW signal in a 800 s interval time Beppo-Sax Catalog 2001 • EXPLORER(CERN) • ON from March to December • T = 2.6 K • Duty Cycle = 91% • Average sensitivity h=4.5 10-19 • NAUTILUS (LNF) • ON from January to December • T = 1.5 K • Duty Cycle = 80% • Average sensitivity h=5. 7 10-19 oct 2006 g.modestino

  18. Cross-correlation analysis . Teff evaluated within a time window of + 400s, centered at tGRB . The data with Teff < 20 mk are selected. 47 GRB are analyzed EXPLORER NAUTILUS oct 2006 g.modestino

  19. Cross-correlation result EXPLORER x NAUTILUS 2001 R(t’) cross-correlation function (averaged on the 47 GRBs) relative to the energy of the two GW detectors. -400s <Dt’< +400s h <1.2 10-18 95% t’(s) oct 2006 g.modestino (ROG Coll), Phys. Rev.D 66102002 (2002).

  20. Zero-threshold search Searching for simultaneous GW signal. • 1991-1999 • GRB list = BATSE + Beppo-Sax • GW detectors = EXPLORER +NAUTILUS • GWB arrival time = GRB Peak Time ± 5 s • GW data background over 30 minute periods • with temperature noise tn< 15 10-3 kelvin • (Peak Time ± 15 min) • Cumulative average and median algorithm ROG Coll. PRD 71, 042001 (2005) oct 2006 g.modestino

  21. Searching for simultaneous GW signal. GRBs Database ROG Coll. PRD 71, 042001 (2005) oct 2006 g.modestino

  22. Data selection Effective temperature Te distribution computed in 1150 time intervals around each GRB peak time N=387 data stretches with Te < 15 mK are selected ROG Coll. PRD 71, 042001 (2005) oct 2006 g.modestino

  23. Searching for simultaneous GW signal. E(0) = 6.33 mk • Combine 387 30 min GW data stretches • For each time delay, the median value Em is extracted GW detector energy as a function of the GW-GRB delay <E> = 6.30 mK s = 0.13 mK h < 3 10-19 ROG Coll. PRD 71, 042001 (2005) oct 2006 g.modestino

  24. Searching for a correlation with sin4q. q S ~ sin2q sin4q correspondingly to the387 selected GRB arrival times and theoretical isotropic distribution The 4 regions of increasing sin4q, separated by vertical lines, correspond to the data subsets separately analyzed. ROG Coll. PRD 71, 042001 (2005) oct 2006 g.modestino

  25. 4/4 Looking for a correlation with sin4q SNR of the excess at zero delay of the median value ROG Coll. PRD 71, 042001 (2005) oct 2006 g.modestino

  26. In progress: Data Analysis GW resonant detectors EXPLORER + NAUTILUS And SWIFT g events An example : Measuring @ t = g trigger time+0.5s Year 2005 g events with z < 1 Interval time for background evaluation :100s oct 2006 g.modestino

  27. Data Taking during 2005 oct 2006 g.modestino

  28. EXPLORER and NAUTILUS -2005 ~ 50 Hz @10-20 Hz-1/2 EXPLORER EXPLORER ~ 50 Hz @10-20 Hz-1/2 NAUTILUS 10-21 Hz-1/2 ~ 30 Hz @10-20 Hz-1/2 oct 2006 g.modestino

  29. In progress: Output of the cumulative algorithm applied to EX+NA j=1,23 N=23 g SWIFT events (11 EX+12 NA) Red -Sampling time 3.2 ms Black - Integrating on  0.5 s K • Ej(t) / N gtrigger time oct 2006 g.modestino S

  30. In progress: Testing with Cosmic Rays Detection Apply the same procedure: GW resonant detectors EXPLORER + NAUTILUS And Cosmic Rays Analyze a similar (statistically) sample: Measuring @ t = CR trigger time+0.5s Year 2005 26CR events (with multiplicity>2000 part/m2) Interval time for background evaluation :100s oct 2006 g.modestino

  31. Output of the cumulative analysis applied to EX+NA j=1,26 N=26 EAS events (13 EX+13 NA) Red -Sampling time 3.2 ms Black - Integrating on  0.5 s K • Ej(t) / N EAS trigger time oct 2006 g.modestino S

  32. Search for GW Burst Signal Sensitivity of bar detectors oct 2006 g.modestino

  33. Sensitivity of the bar detectors IGEC2 oct 2006 g.modestino

  34. Search for GW Burst Signal Upper limit for GW burst detection Class. Quantum Grav. 23 S57-S62 (2006) oct 2006 g.modestino

  35. ROG - The two cryogenic detectors - NAUTILUS LNF-Frascati bar length L = 3m mass = 2300 Kg material Al5056 resonance ~1 KHz temperature = 0.1 K - 2 K CERN EXPLORER oct 2006 g.modestino

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