coherent WaveBurst Review Meeting 07 May 2009 09:00 Pacific / 12:00 Eastern
Agenda: Thursday 07 May 12:00 Eastern
Dial-in number: 1 800 704 9896 International dial-in: +1 404 920 6472 Conference code: 5374 2349 #
AttendancePatrick (minutes), Marco, Francesco, Sergey, Virginia, Stas, Romain, Michele, Irena, Gabriele.
Updates on Action Items
- RG reran Q scans on H1H2 livetime loudest missed injections. Not yet set up web pages; will report next week.
cWB Background ChecksFS led us through the background check web page.
- Background estimated using circular buffer time-shift of first detector with respect to the others. Gives approximately constant livetime vs. lag, rather than linearly decreasing with lag.
- All segments have observation time of 300-600 sec.
- HFS: All lags are at fixed whole-number steps of 1.56 sec, with lag number 0, 1, 2, ..., 192 (max).
- HFS used final rho threshold of 4.3. For correlated plots keep all rho > 3.5 or 3.7 to have high enough statistics. All other cuts are applied as in search.
- Histograms of time differences between all pairs of events. Delays up to 600 sec (maximum possible delay in a job), approx 10000 bins. These determine FFT scales.
- H1H2L1V1 combination: FFT of delay histogram shows weak lines at frequencies that are multiples of 1/1.56 Hz. This is a weak effect of the time lags. FS hypothesizes that these are due to weak H1H2 coincidences that show up in the background in coincidence with weak L1 events.
- H1H2L1 combination: Lines are stronger, but largely suppressed for rho > 3.7.
- H1L1V1: Strong downward trend in number vs. delay. Perhaps due to short segments? Final threshold is very high (6) for this noisy combination.
- Reviewers: No serious concerns.
UL Error BudgetVR led us through this page [wiki].
- Sources of error: V4 (LIGO) and V2 (Virgo) calibration uncertainties, systematic discrepancy between V3 and V4 (LIGO only), LIGO error in converting h(f) to h(t), antenna pattern correction. Numbers taken from Brennan Hughey's web page.
- PJS: Is 200 microsec LIGO-Virgo error for V3 tested? VR: Yes. Calibration errors page tested delays this large. SK: Effect mainly to produce an error in the sky position.