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S5 Qpipeline High-Frequency Review Telecon 28th of August 2008 11:00 Eastern

Agenda and minutes of the S5 Qpipeline High-Frequency Review Telecon for Thursday the 28th of August at 11:00 Eastern time.

Agenda and Contact Info


Action items
  1. Calibration update
  2. H1H2 analysis update
  3. H1H2 Phase Shift Update
  4. Update on paper draft
  5. AOB

Contact Info

  InterCall telecon service:

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    participant code: 251 288 9495#


Brennan: Talked to Brian O'Reilly about V3 calibration. Still no real info, 
but that's just how things stand.

H1H2 - see
Jackie: Brennan ran on injections with large phase offsets and calibration 
uncertainties and found that it killed the NULL stream for high frequencies
(> 5kHz). Therefore decided to not use null stream veto.
Ran CorrPower to determine gamma distribution. Re-ran Q-pipeline on 
sine-Gaussian injections to work out efficiencies and chose cutoffs on Z 
and correlated energy (CE).
Jonah: Why is the slope on the plots (Energy Threshold for Maximal Detection
of Software Injection) going down?
Jackie: X-axis should be relabelled to clear this up.
Jackie: Conculsion not apply the null stream and have a gamma cut of gamma>=
10.06 and Z>=100, giving false alarm rate of 1/100 (in terms of livetime)

H1 and H2 phase studies (using full detector response not in LWL approxmation)
- see
Brennan - What I was saying last week was wrong, due to a bug in how I was
doing the calculation.
Phase shift between H1 and H2 is not a particularly severe effect. At high
frequencies this can be as much as 20 degrees, but this can be handled with
very small loss of efficiencies. This also only happens rarely and at 
points when the amplitude response is small (see first plot). Generally
phase difference will be of order 4 degree, but this is easily handled within
the search. Can cofidently say that this is not a problem.
Jonah: What is the white in the plots.
Brennan: It's just when it is essentially zero.
Jonah: Have we done any injections to test that the H1 H2 analysis is robust
against phase shift.
Brennan: Yeah, these have been done and shown at some burst calls. Phase offests
of around 10-20 degree and amplitude offsets of around 1.35 don't seem to cause
much loss of efficiency - maybe of order 1-2%. It seems robust. This should
be added to the documention that we have for completeness.
Jonah: CorrPower is doing the cross-correlation with H1 and L1?
Brennan: It's doing it for all three IFOs, with time shifts approriate for 
H1 - H2 and LHO - L1.
Jonah: It's all looking good :)

Peter's comments on the paper
Brennan: Peter sent some comments - mainly minor edits/typos, but a few more
substantial issues.
point 7 - Now results use the official end of LIGO year one. Changes results
very slightly although the difference in counts is less that 0.1%
point 18 - what should we do regarding this point?
Jonah: We should probably just follow the convention of the other papers - S4
paper and S5 low frequency paper.

Brennan: probably be more suggestions from rest of burst group - deadline is
next wednesday. I'll just continue to update the paper as suggestions come in.
Forward any responses to reviewers.

Efficiency for waveforms
Michele: Want to discuss studies into efficiencies to waveforms. 

Jonah: Still got to look through Michele's astrophysically motivated, but it
is on to do list

Matt: Has the review summary table been updated?
Jonah: Yes, it has - have a look and see if there's anything to add.


Brennan Hughley, Jonah Kanner, Matt Pitkin, Michele Zanolin, Jackie Villadsen