LIGO-G Z Detector characterization for LIGO burst searches Shourov K. Chatterji for the LIGO Scientific Collaboration 10 th Gravitational Wave Data Analysis Workshop University of Texas at Brownsville 2005 December 14

LIGO-G Z Shourov Chatterji - GWDAW December 14 2 Detector characterization tasks Monitor a large number of auxiliary interferometer and environmental channels Near real time feedback for control and commissioning Histograms of trigger significance Measures of detector non-stationarity Trigger rates as a function of time Develop event based vetoes Time lag correlation studies of veto efficiency Use simulated burst injections to test for veto safety Reject epochs of poor data quality Detailed time and frequency domain studies of interesting events Existing burst search tools can be applied to these tasks

LIGO-G Z Shourov Chatterji - GWDAW December 14 3 KleineWelle trigger generator Identifies statistically significant clusters of signal energy in the dyadic wavelet transform of a whitened timeseries. For S4, triggers were generated for ~50 interferometer and environmental channels at each LIGO site. kleineWelle triggers used to: Provide daily feedback for data quality investigations Study correlation between triggers and candidate bursts to develop safe and effective event based vetoes Evaluate effect of epoch vetoes based on data quality flags (dust, enhanced seismic activity, etc.)

LIGO-G Z Shourov Chatterji - GWDAW December 14 4 KleineWelle daily statistics

LIGO-G Z Shourov Chatterji - GWDAW December 14 5 Tests for correlated triggers Time between GW and auxiliary channel triggers:

LIGO-G Z Shourov Chatterji - GWDAW December 14 6 Event based vetoes Identify channels that show a statistically significant correlation with the gravitational-wave channel triggers Avoid false rejection by studying simulated bursts that are physically injected into the detector Unsafe channelSafe channel

LIGO-G Z Shourov Chatterji - GWDAW December 14 7 Data quality epoch vetoes Reject periods of anomalous detector behaviour Based on kleineWelle, BurstMon, and many other studies For S4, a number of epoch vetoes were applied: One of two Hanford detectors not in lock 30 seconds before the end of each lock segment Increased seismic noise at the resonant frequency of the seismic isolation system Anti-symmetric port photodiode saturation High wind velocities at Hanford Injection of simulated gravitational wave signals For S4, repository of data quality flags maintained on web For S5, moving to a database solution

LIGO-G Z Shourov Chatterji - GWDAW December 14 8 BurstMon Implementation of WaveBurst unmodeled burst search algorithm applied to rapid detector characterization Near real-time figure of merit for detector non-stationarity Fraction of detected events that consist of clusters of more than two time-frequency pixels:

LIGO-G Z Shourov Chatterji - GWDAW December 14 9 Event display Permits a detailed study of a large number of interferometer and environmental channels around the time of interesting events Results published on-line as html reports Displays lock segment information Displays time series and time-frequency spectrograms Guide search for potential veto channels Incorporates parameter estimation for candidate events Applied to candidate events and simulated burst injections For S5, automatically applied to study the most significant events on a daily basis

LIGO-G Z Shourov Chatterji - GWDAW December Event display example Hardware injection into H1 and H2

LIGO-G Z Shourov Chatterji - GWDAW December Event display example (cont.)

LIGO-G Z Shourov Chatterji - GWDAW December Q Scan Based upon Q Pipeline search for unmodeled bursts Multi-resolution time-frequency search for statistically significant excess signal energy See tomorrow’s poster for more information Easy to use configuration utility permits scanning of hundreds of interferometer and environmental channels Displays channels with statistically significant signal content Produces multi-resolution time-frequency spectrograms Currently incorporating into event display: Automatically applied to most significant events, simulated burst injections, candidate events, etc. Results published on web

LIGO-G Z Shourov Chatterji - GWDAW December Q Scan: hardware injection Simulated 235 Hz Q 9 sinusoidal Gaussian burst physically injected with SNR ~150 into the H1 detector Search for potentially related time-frequency structure in auxiliary and environmental channels Anti-symmetric port orthogonal phase signal not a safe veto

LIGO-G Z Shourov Chatterji - GWDAW December Q Scan: environmental injection Intentional seismic and acoustic excitations used to study environmental coupling Related signal observed in gravitational wave channel and accelerometer mounted on anti-symmetric port output table Suggestive of potential veto channel