LIGO-G050650-00-Z Detector characterization for LIGO burst searches Shourov K. Chatterji for the LIGO Scientific Collaboration 10 th Gravitational Wave

LIGO-G050650-00-Z

Detector characterizationfor LIGO burst searches

Shourov K. Chatterji

for the LIGO Scientific Collaboration

10th Gravitational Wave Data Analysis Workshop

University of Texas at Brownsville

2005 December 14

Shourov Chatterji - GWDAW10 - 2005 December 14 2LIGO-G050650-00-Z

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


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.)


KleineWelle daily statistics


Tests for correlated triggersTime between GW and auxiliary channel triggers:


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 channel Safe channel


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


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:


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


Event display example

Hardware injection into H1 and H2


Event display example (cont.)


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


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


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

Documents

LIGO-G050650-00-Z Detector characterization for LIGO burst searches Shourov K. Chatterji for the LIGO Scientific Collaboration 10 th Gravitational Wave