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Review Committee Meeting Monday 26 February 2007 12:00 Pacific / 15:00 Eastern

Minutes: Monday 26 February 2007 12:00 Pacific / 15:00 Eastern

Agenda and Contact Info


  1. Brief report on status of the GRB paper.
  2. S3 LIGO-AURIGA paper

Contact Info

InterCall telecon service:
   Phone: 1-866-380-5536, participant code: 435 672 9587 #
   International callers ++1-816-249-4731 with same code
   International access numbers (~10 cents/min surcharge for LIGO Lab):
      Paris 017 080 7156 ;
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   Handy participant command:  Press *6 ["*M"] to mute, #6 to unmute


  1. GRB Status: Isabel still working on draft. Nearly done.
  2. LIGO-AURIGA Search:
    • Laura gave an overview of the search:
      • Project Summary [ HTML ]
      • More Material [ HTML ]
      • Technical Document [ PDF ]
    • Discussion of correlated background: remove correlated time slides. Some concern about the reliability of the background.
      • Independence of background estimates affects the uncertainty in the background but not the background estimate itself.
      • Is it possible that a time slide contains a different AURIGA trigger? If so, how often?
      • What if there are a number of GWs in the data. Are they actually excluded from the background? Answer: there were 31000 AURIGA triggers so GWs would only make a very small fraction. But if there were a strong GW signal in, say, H1-H2. How many background events would this cause?
    • Software injections: AURIGA estimates a 1-sigma uncertainty using an internal Monte Carlo. Typically around 17 ms; as high as 40 ms. But CorrPower takes 100 ms around trigger time, so this dominates. AURIGA algorithm is tuned for signals lasting less than 10 ms.
    • Unknown lines in AURIGA spectrum. Adaptive algorithm to track lines but cannot account for short-term variability. Lines are notched out with a 1 Hz wide notch. Still expected to contribute to the trigger rate. Question about the line that seems to be shared between AURIGA and H2 at around 865 Hz. Not clear what this line is in either instrument.
    • Epoch veto used by AURIGA: is it safe? Can a GW contribute to the out-of-band power? Safety has been checked for signals with SNR up to 100. Are these for SG signals or for Gaussians? These are for Gaussians.
    • Antenna pattern plot: what exactly are "latitude" and "longitude"? These are locations on the sky corresponding to the local vertical of a point on the Earth at the specified latitude and longitude. Latitude is measured N of equator and longitude is measured E of Greenwich. Need to check these responses.
    • Calibration uncertainties: estimate AURIGA calibration uncertainty of 10%. How does this affect the result? Is this a 10% scaling in the UL? Not clear because the CorrPower threshold is used to constrain the final events, not the AURIGA threshold.
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