STATUS of BAR DETECTORS G.A.Prodi - INFN and University of Trento International Gravitational Event Collaboration - 2 ALLEGRO– AURIGA – ROG (EXPLORER-NAUTILUS)

outline updates on performances of detectors current organization of IGEC-2 recent and current observations plans for future joint observations target performances of detector upgrades

burst sensitivity, rms [Hz -1 ] IGEC-1 S hh of IGEC-2 detectors IGEC-1

Mode Hz Mode Hz frequency stationary performances: time-frequency plots ALLEGRO Time (10 hours)

frequency stationary performances: time-frequency plots AURIGA Time (10 hours) Mode Hz Mode Hz Mode Hz

Mode Hz Mode Hz frequency stationary performances: time-frequency plots EXPLORER Time (10 hours)

frequency stationary performances: time-frequency plots NAUTILUS Time (10 hours) Mode Hz Mode Hz

preliminary duty cycles of detectors in 2005 ALLEGRO:95% AURIGA: 90% after suspension upgrade (may 19 th 2005) 45% before “ “ EXPLORER:83% NAUTILUS: 90% epoch vetoes are still being defined… the IGEC-2 observatory have been in at least three-fold coincidence operation for most of tests show that detectors are affected by a very low rate of noise outliers - work in progress on comparison and cross- validation of the detectors results, based on raw data exchange: talk by Francesco Salemi in “Detector Characterization”

TRIGGERED SEARCHES by Gamma events Search for bursts in coincidence with 387 GRBs (BeppoSAX and BATSE): cumulative upper bound of h = 2.5 · in a time window of 10s P.Astone et al. (ROG Collaboration), Phys. Rev. D 71, (2005) - Search for gw ringdown in coincidence with the Dec giant flare from SGR : upper limit which invades part of the parameters’ region of existing models in the AURIGA bandwidth Baggio et al. (AURIGA collaboration), Phys.Rev.Letters 95, (2005)

149 days upper limit assuming a gaussian pulse  = 0.1 ms ROG: BURST SEARCH on 2003 data time coincidence analysis per sidereal hour on 2003 data of EXPLORER and NAUTILUS excluded the rate-amplitude region formerly indicated by a similar analysis on 2001 data P.Astone et al. (ROG Collaboration), Proc. Amaldi 6, (2005)

IGEC-2 coordination of observation times: - IGEC-2 groups are planning the interruptions of the observation time to maximize the time coverage (i.e. to keep at least 3 out of the 4 detectors in coincidence operation at all times). see our schedule: > IGEC2 calendar IGEC-2 run coordinators: W.Johnson (chair), V.Fafone (deputy), L.Taffarello - IGEC-2 provides real time information on detectors status to other experiments. AURIGA and ROG basic information can be automatically queried via web pages. see for instance: > present status in the near future, we plan to add real time information on the achieved sensitivity to standard transient signal waveforms - investigation started on the feasibility and effectiveness of an Early Warning System (in the footpath of SNEWS) see poster by R.Terenzi and R.Sturanihttps://sam.phys.lsu.edu

IGEC-2 search for bursts data are available since may 2004-present. Observation will continue at least for yr priority to the anaIysis of the last semester (May.-Nov.2005), since AURIGA improved its duty cycle and up to the start of LIGO S5. Data exchange is planned by end of New: blind data exchange for a blind data analysis: Rigid time shifts has been secretly added by each group and will be circulated only when the analysis procedure is agreed in detail Network analysis based on IGEC-1 experience: use a priori information to improve the network search (signal template, testing source locations, common search thresholds on amplitudes, etc.) –Nfold-time coincidence search with adapting order N –a priori control of false dismissal (conservative bound). –Data selection, time coincidence search and accidental coincidence estimation in the footpath of IGEC-1 Scientific coordinator: G. Prodi; vice-coordinators: W.Johnson and M.Visco

Expected performances of IGEC-2 Triple coincidences: 10 6 time shifts, no accidentals on 9.3 days false alarm rate /Hz high statistical significance in case of gw candidates Double coincidences: lower false alarm rates than for IGEC-1 rate [year –1 ] search threshold dashed region excluded with probability > 90% expected upper limit improvement by IGEC-2 1 month 1 year IGEC-1 upper limit

STOCHASTIC BACKGROUND SEARCHES by BARS & INTERFEROMETERS - ALLEGRO & LIGO S4: first stochastic results from a hybrid observatory see talk by John Whelan et al. (LSC) in “Stochastic searches” - VIRGO & INFN BARs: playground h(t) data exchange using VIRGO C6 and C7 commissioning runs to test analysis procedures on real data see poster by G.Guidi, G.Cella et al. (AURIGA, ROG & VIRGO) Expected SNR 4 per unit bandwidth, integration time and  gw

BURST SEARCHES by BARS & INTERFEROMETERS AURIGA & LIGO S3: first burst analysis from a hybrid observatory. Mainly of methodological relevance, based on a cross-correlation search on LIGO data triggered by AURIGA candidate events. Tuning phase completed. see poster by F.Salemi et al. (AURIGA & LSC) VIRGO & INFN BARs: characterization of network efficiency and comparison of coincidence search methods on real data (VIRGO C6 & C7) see poster by G.Guidi et al. (AURIGA, ROG & VIRGO) efficiency for cos-gaussian 900Hz Q9 uniform polarization and sky distribution AURIGA&H1&H2 coincident operation: 74 hr estimated false rate 0.5  Hz AURIGA sets overall efficiency h rss50% this search  2x LIGO only search

T = 0.12K, double gap transducer (11  m and Q=1.5·10 6 ) double SQUID (L 0 =2.5 H, k=0.7). T eff ≈ 7  K SQUID noise saturation at 200 mK taken into account. current Quality factors are assumed increased bias field inside transducer AURIGA NAUTILUS EXPECTED SHORT TERM PROGRESSES: cooling to 0.1 K

FINAL REMARKS growth of the efforts towards joint observation between bars and interferometers; The hybrid observatory is useful when aiming at a gw detection. Benefits: - improved the time coverage in burst searches - improved statistical significance of a gw candidate (if it falls within the reach out of bar detectors) - increased physical information on the gw direction from arrival times additional amplitude information solution of the inverse problem - more discrimination against disturbances Limits: lower reach out of bar detectors good opportunities in the medium term with ultracryogenic resonant detectors

extra slides

SQUID energy resolution  (  ) vs year — in the detector ● coupled to a LC resonator two stage LHe T ultracryogenic AURIGA 0.1 K Detector T eff  4 T n

Detection efficiency for bursts Maximum detection efficiency for transients with flat Fourier amplitude at the detector frequencies (  900 Hz) Efficiency of the AURIGA  matched filter for Sine-Gaussian waveforms: S-G central frequency [Hz] SNR   matched filter SNR SG filter matched to the Sine-Gaussian computed for the AURIGA detector Q SG - 2

Arrival time estimation AURIGA arrival time estimation for  signals by Monte Carlo injections of software signals IGEC-2 is not yet able to measure light time delays among detectors - 2

Exchanged candidate events amplitude histograms of exchanged events EXPLORER NAUTILUS AURIGA Event counts Event amplitude H [Hz] - 2

Self correlograms of exchanged events Histograms of the time lags among events of the same detector: much more “Poissonian” than in IGEC-1 AU EX NA 50 seconds - 2

cross correlograms of exchanged events Histograms of the time lags among all events from two different detectors: Poisson model as in IGEC-1 AU-EX AU-NA EX-NA - 2