Palma de Mallorca - October 24 th, 2005 IGEC 2 REPORT International Gravitational Events Collaboration ALLEGRO– AURIGA – ROG (EXPLORER-NAUTILUS)

Palma de Mallorca - October 24 th, 2005 Introduction to IGEC2 Data analysis methodology Cross validation of data Progress in coincidence analysis OUTLINE OF THE TALK

Palma de Mallorca - October 24 th, 2005 IGEC First experience of extended search of multiple coincidence using data of 5 resonant detectors: ALLEGRO, AURIGA, EXPLORER NAUTILUS and NIOBE. IGEC May  2005 Feb  … A new agreement for a joint search for gravitational waves, now 4 detectors, NOIBE was dismissed. -ALLEGRO, AURIGA and ROG spokespersons unanimously decide actions/agreements. Stronger coordination of joint observations. -The operation are based on a task force, coordinated by G. Prodi, vice-coordinators W.Johnson and M.Visco THE NEW IGEC

Palma de Mallorca - October 24 th, 2005 A DIRECTIONAL 4-ANTENNAE OBSERVATORY The four antennas receive an identical signal, independently from the source

Palma de Mallorca - October 24 th, 2005 NETWORK ANALYSIS following IGEC1on parallel detectors -The IGEC analysis was conceived as a N-fold analysis with adaptive N of parallel detectors. -The analysis is based on lists of candidate events produced selecting with an adaptive threshold data produced by a filter matched to a delta. -The use of amplitude information together with a directional search allows an a-priori control of false alarm and false dismissal -The time window is adapted to SNR -The search parameters are tuned with a blind analysis -The data are cross validated DATA ANALYSIS METHODOLOGY

Palma de Mallorca - October 24 th, 2005 Exchange of one day of raw data to cross validate the filter pipeline - cross validate data and characteristic of the single detector - measure the efficiency of the observatory Exchange of candidate events for one month of data (December 2004)- blind - study of the background - tune of the coincidence analysis pipeline PROGRESS OF IGEC2

Palma de Mallorca - October 24 th, 2005 IGEC IGEC …. FROM IGEC1 TO IGEC2

Palma de Mallorca - October 24 th, 2005 ARRIVAL TIME ESTIMATION For  signals by Monte Carlo injections of software signals (Auriga)  (s) For  signals from cosmic ray (Explorer)  = 2.3 ms The bandwidth improvement of the detectors gives a time resolution larger of about a factor 100 respect to IGEC1

Palma de Mallorca - October 24 th, 2005 To aim a cross validation of data one day of raw data was exchanged The data were filtered with the AURIGA Data Analysis filters The first step completed is the analysis of ROG antennae, analysis of ALLEGRO in progress The first results suggest a good agreement between the different pipelines. CROSS VALIDATION OF DATA

Palma de Mallorca - October 24 th, 2005 PERFORMANCES Spectrograms Continuous performances of all experiments NA AU EX 5000 s

Palma de Mallorca - October 24 th, 2005 DATA QUALITY - SNR OF EVENTS All the detectors show a gaussian behavior NA AU EX

Palma de Mallorca - October 24 th, 2005 DATA QUALITY: DISTRIBUTIONS OF EVENTS Few events with SNR>6 in all the experiments NA AU EX

Palma de Mallorca - October 24 th, 2005 DETECTION EFFICIENCY Injected 1800 signals of SNR=6 within 1h NA AU EX

Palma de Mallorca - October 24 th, 2005 OPERATION TIME - DECEMBER 2004 AURIGA- EXPLORER- NAUTILUS Single 4.63 days Double 16.43days Triple 9.36 days ALAUEXNA AL0 AU EX NA %89 %86 %~90 % from May 2004 DOY N

Palma de Mallorca - October 24 th, 2005 The sensitivity is stationary There is an enhancement of about a factor 3 respect to IGEC 1 EXCHANGE THRESOLD Percentage of time with the adaptive threshold T smaller than H

Palma de Mallorca - October 24 th, 2005 AMPLITUDE OF EXCHANGED EVENTS

Palma de Mallorca - October 24 th, 2005 SELF CORRELOGRAM OF EXCHANGED EVENTS Histograms of the time lags among events of the same detector: much more “Poissonian” than in IGEC-1 AU NA EX 50 seconds AU - now

Palma de Mallorca - October 24 th, 2005 PRELIMINARY RESULTS OF 2-FOLDS COINCIDENCES Statistics of the accidentals are in agreement with the model EXPLORER NAUTILUS Number of accidental coincidences

Palma de Mallorca - October 24 th, 2005 The analysis must be oriented to the detection as we expect from LIGO after S5 an upper limit far from present resonant detectors sensitivity. Complete the preliminary analysis of cross validation on raw data. Complete the preliminary analysis on one month of data to tune the analysis pipeline. Exchange a larger period of data for the final analysis PROGRAM FOR NEAR FUTURE