Presentation on theme: "S3/S4 BBH report Thomas Cokelaer LSC Meeting, Boston, 3-4 June 2006."— Presentation transcript:
S3/S4 BBH report Thomas Cokelaer LSC Meeting, Boston, 3-4 June 2006
Plan ● Target waveforms ● Data in S3, S4, expected distance to be probed ● Filtering and template bank ● The tuning of the searches ● Status of S3 ● Status of S4 ● Conclusions
Target waveforms ● Black hole binaries without spin effects. The two individual component masses are in the range [3 40] solar mass in S3 and [3 80] solar mass in S4 (the difference comes from the effect of the lower cut off frequency set to 70 and 50Hz. – The length of the waveforms are 1.5 seconds at most in S3 and 3.8 seconds in S4. – The injected waveforms used in our simulations are based on different physical waveforms such as Pade, Taylor, EOB. – The individual masses are uniformly distributed.
The data ● Data analysed in S3/S4 data – 124 hours of H1H2L1 data, 604 of H1H2 data in S3. – 365 hours of H1H2L1 data, ~50 hours in H1L1 and H1H2. ● Expected horizon distance for an optimally oriented waveform with an SNR of 8 using S3/S4 data gives distance up to 40 Mpc in S3, and 90 in S4.
The filtering The templates and filters used in this analysis are based on the BCV template family which are phenomenological templates that incorporate a phase depending on 2 mass-related parameters 0 and and a frequency dependent amplitude correction proportional to a parameter. The templates are computed in the frequency domain and end at a frequency defined by f cut. The amplitude of the template is
Template bank ● The spacing between templates ensures that 95% of signal to noise ratio of any incoming signals is recovered. ● The bank is defined in the three dimensions of the search. The number of templates fluctuate since the template banks are computed every 2048 seconds taking into account the noise spectral density of each detector. f
Tuning of the search ● Injections are performed in the data sets in order to tune the parameter ( injections in each search). done ● Coincidence parameters in the dimension of the search (time, and two mass parameters) are defined by comparing our background estimate and the recovered injections. done ● Removing triggers which shows suspicious value of alpha (BCV parameter). done ● Applying amplitude cut in H1H2 coincident triggers done ● Applying H1H2 consistency check on H1L1 and H2L1 triggers done ● Delta psi0/ Delta psi3 cut done ● No further tuning to be done in S3/S4.
S3 status ● S3 box is opened ● H1H2L1 : a few triple coincidences consistent with background. ● H1L1 triggers in triple ifo data : gives zero lag consistent with time slide histograms but large snr triggers in L1. ● H1H2 triggers in triple or double ifo data : zero lag consistent with time slides in the triple ifo case, excess in the double ifo case. Large triggers appears. ● Loudest event in H1H2 (Snr of 150 in H1 and 23 in H2) partly investigated : noise in sensing control.
S3 to be done ● Final efficiencies – Efficiencies in single detector done – Final efficiencies in coincidence using the final loudest events to be done ● Upper limits ● Investigation on the relevant candidates.
S4 status ● Tuning is done. ● Time slides and zero lag triggers investigated on playground data : H1L1, H2L1 coincidences in triple ifos data give consistent rates. ● No triple coincidences ● H1H2 gives a slight excess of rate in triple ifo data. Some have been investigated leading to improvement in the veto segment list. ● H1H2 zero lag in double data is consistent with background. ● Investigations done of some of the loudest triggers : interpretation on going.
Conclusions ● S3 : box opened. The zero lag triggers are consistent with time slides rates although some excess appears in H1H2. – To be done ● Investigations on the loudest triggers ● Final efficiencies and upper limits ● S4 : box to be opened in a time scale of 2-3 weeks once final investigations on the loudest triggers is done. – To be done ● Final efficiencies and upper limits