Burst Figure of Merit Julien Sylvestre LSC Meeting, March 2004 LIGO Laboratory

Requirements Real time One number Orthogonal to other FOMs Accurate lag data acquisition by less then 5 minutes One number Orthogonal to other FOMs Accurate Correlates well with our efficiency and background LIGO Laboratory

Proposals: Floating SNR cut End-to-end analysis LIGO Laboratory

Floating SNR cut Process data segments with an ETG every T seconds For each segment, apply a SNR cut so that only N events survive FOM = SNR cut Large glitches affect the FOM Small glitches don’t affect the FOM much For a given signal model, and a calibrated spectrum, get hrss, range, etc. Ran for a month during S3 LIGO Laboratory

End-to-End analysis Inject a (few) waveform(s), process with ETG Do coincidence between all IFOs (optional) Measure background FOM = sqrt(background) / efficiency Requires real-time calibration information Model dependent: short/long bursts, frequency range, etc. Real-time inter-site coincidences demonstrated during S2 LIGO Laboratory

Orthogonality L1, S2 playground 130-400 Hz 300s segment 100 injections per amplitude LIGO Laboratory

Correlation between burst rate and inspiral FOM LIGO Laboratory

Correlations Inspiral range hrss SG153 hrss SG235 hrss SG361 hrss G0.001 Burst rate -0.64 0.52 0.59 0.56 0.60 -0.80 -0.86 -0.78 -0.75 0.41 0.85 1 0.64 Sqrt(bac. rate) / (hrss SG361) 0.68 -0.53 -0.63 (decorrelated) 0.02 -0.07 -0.14 -0.16 LIGO Laboratory

Conclusion Reasonably easy to define and implement a burst FOM Key question #1: what new information is this FOM generating? Key question #2: how good is this FOM at predicting the quality of the burst analysis? LIGO Laboratory