for the Collaboration

1
Status of inspiral search in C6 and C7 Virgo data

• for the Collaboration
• GWDAW 2005

2
C6 C7 runs
Optimally oriented 1.4,1.4 M? (SNR8)

• C6
• 14 days
• 86 duty cycle
• (in science mode)
• Factor 2 variation in the horizon over the course
  of the run
• C7
• 5 days
• 65 duty cycle
• Detector sensitivity also not stationary

3
Inspiral online analysis

• Both pipelines, Merlino and MBTA, ran online
  during C6 and C7, getting data from online
  h-reconstruction
• Monitoring information provided
• Lists of loudest events
• Plots for monitoring web pages

MBTA
Hardware injections
4
C6 hardware injections

• 56 inspiral hardware injections
• 4 different periods, 1.4,1.4 M?, SNR ranging
  from 15 to 25
• All detected
• Check timing and mass estimation accuracy
• Check SNR recovery
• 10 loss might be due to sensitivity
  non-stationarity

MBTA
5
C7 hardware injections

• 2 periods of inspiral injections
• 1.32 , 1.36 M?, SNR 20
• Detected with good accuracy
• Issue with some injections having a bad ?2
• under investigation

Merlino
6
Non-stationarities C6

• Evolution in time of the frequency at which half
  of the SNR is integrated
• ? Change in the shape of the PSD

7
Non-stationarities C7

• Variations of the PSD on short time scales not
  obvious to follow with adaptive mechanisms

8
C6 analysis quality cuts (I)

• C6 first six days
• Horizon very unstable
• Bump going up and down in 100-300 Hz region of
  sensitivity curve (stray beam)
• Leave this first part of the run aside
• Focus on remaining 8 days

9
C6 analysis quality cuts (II)

• Skip first five minutes after relock
• Use auxiliary channels to identify obvious
  sources of high SNR triggers, e.g.
• Saturations in frequency stabilization loop
• Glitches on actuator coil drivers

10
C6 analysis SNR distribution
MBTA
Inspiral injections

• 0.9 - 3 M? analysis
• 170 hours of data
• Very loud events eliminated by basic quality cuts
• Tail of distribution still extends to high values
• Even strong, the hardware injections (in red) do
  not dominate the noise

Burst injections
11
C7 analysis

• 0.9 - 3 M? analysis
• 80 hours of data
• C7 SNR distribution slightly better than C6

12
C7 software injections

• Systematic studies (efficiency, ?2 test) with
  Merlino on software injections performed during
  C7 quiet period
• ? see poster by L.Bosi

13
C6 a posteriori vetoes

• SNR distribution between low and high frequency
  bands
• ?22 bands

• Shawhan-Ochsner veto
• Look at output of matched filter in time domain

14
C6 SNR with vetoes

• Bulk of distribution unchanged
• High SNR tail definitely improved
• Hardware injections almost stand out

15
C7 vetoes

• Behavior similar to C6

16
C7 SNR with vetoes
?22 bands lt 40

• Loudest surviving event has SNR lt 20

Samples above threshold lt 30 ?22 bandslt 40
Samples above threshold lt 30
17
Conclusion

• C6 and C7 data have extra-galactic sensitivity to
  neutron star inspirals
• Not science quality data
• Detector behavior glitchy and not stationary
• Preliminary analysis
• Two pipelines operational for online and offline
  analysis
• Hardware injections, quality cuts, a posteriori
  vetoes
• Pursue investigations
• Learn as much as we can from those data in order
  to get prepared for the science data to come next
  year