Status of inspiral search reviews Alan Weinstein (LIGO Laboratory / Caltech)

1. Status of inspiral search reviews Alan Weinstein (LIGO Laboratory / Caltech) For the LSC Internal review committee: Vicky Kalogera, Bill Kells, Alan Weinstein, John Whelan, Laura Cadonati, Duncan Brown LIGO LSC Meeting June 3, 2006 LIGO- G060260-00-Z LIGO-G060260-00-Z

2. Review Process • Roughly ~weekly review telecons since the March meeting. • Reviews greatly facilitated by well-organized, detailed elog pages assembled by analysis principle authors. • Also facilitated by the commonality amongst all searches currently under review (pipeline, data handling procedures, bookkeeping for observation time, vetoes, etc). • All the code is in lal, lalapps, pylal, etc…, in CVS, tagged. • Code review for features unique to the BBH search (BCV templates, template bank generation, coincidence code…) LIGO-G060260-00-Z

3. Analyses under review • Binary Neutron Stars (BNS, 1-3 Msun): S3 and S4 • Both boxes opened, no detections, background and efficiencies reviewed • Binary MACHOs (AKA PBHs, 0.35-1 Msun): S3 and S4 • Both boxes opened, no detections, background and efficiencies reviewed • Binary Black Holes (BBH, 3-40 Msun): S3 and S4 • S3 box opened, no detections, background and efficiencies reviewed • S4 box to be opened soon Upper Limits and Systematic Errors: • In all cases, work is in progress to fold in measured efficiencies with source model (spatial distribution, component mass distribution) to extract astrophysical upper limit (events/y/L10 ) • Evaluation of systematic errors (MC stats, calibration, waveform modeling, source population modeling) in progress. • Review of upper limits and systematics have begun, converging quickly. LIGO-G060260-00-Z

4. Coming up before August meeting • Complete the review of S4 BBH analysis (box opening soon) • Review astrophysical upper limit calculations • Results paper for S3/S4 BNS/MACHO/BBH • Longer papers on methods, astrophysical source models By August, these six analyses, reviews, mature paper draft should be complete – at least, this reviewer hopes so! • Then on to (not necessarily in this order): • S5 BNS • S3 Spinning BBH • Detection confidence follow-ups • Coherent follow-up • Ringdown search • GRB/Inspiral coincidence • Parameter estimation: Time-domain-templates, MCMC • … LIGO-G060260-00-Z

5. Elements of the Search that have been reviewed • Data segment selection, Data quality flags, vetoes • Template waveforms • Template bank generation, bank size vs time • Sensitivity: Inspiral horizon distance (AKA range, = 2.26*sensemon) • Hierarchical pipeline • Parameter estimation for coincidence window tuning • Coincidence cuts in time, m1/m2, psi0/psi3… • chisq, rsq, alphaf cuts. • H1/H2 amplitude consistency cut • DQ flags, vetoes applied at various stages of the pipeline • Time slides for accidental background estimation • Injections, missed injections, efficiency vs effective distance(s) • Zero lag candidates • Follow-up of loudest events (trigger parameters, Qscans, etc) LIGO-G060260-00-Z

6. double-and-triple-coincidence times • Various double-and-triple-coincidence cases / data sets: • H1H2, H1L1, or H2L1 double coincidence in 2-IFO livetime • H1H2, H1L1, or H2L1 double coincidence in 3-IFO livetime • H1H2L1 triple coincidence in 3-IFO livetime • Only consider times when H1 and H2 are both in-lock (but not necessarily both in science mode). Also require amplitude consistency between H1/H2. Some of these combinations are not relevant in some cases. • Need to keep track of livetime, vetoes, background time slides, etc for all the relevant cases. • Independent scripts, going from segments lists through all stages of the DAG. The bookkeeping is nontrivial, especially given the complexity of the Condor DAG. • These timing checks are now reviewed. Automated, routine, and common to all inspiral group searches. LIGO-G060260-00-Z

7. Detection statistic • SNR is not the best way to distinguish signal from background;use “effective SNR”, taking into account chisq test of signal consistency, constructed to give a rough sense of the ~ average SNR of the coincident trigger. • Need to combine signal / background discriminators from 2 or more coincident detectors as a single measure of coincident trigger strength: “Combined SNR”. • This helps, to give guidance on where an analysis needs improvement. LIGO-G060260-00-Z

8. Background estimation via time slides • Anomalies are seen in many cases. • Expected, for H1/H2. • In other cases, could just be (extreme?) statistical fluctuations. • Continued worry about this method of background estimation (especially for H1/H2, obviously). • No better ideas or checks have emerged. • For now, analyze the (considerable amount of) data; use for upper limits, look carefully at the (small number) of potential detection candidates. S4 BNS, H1H2 S4 BNS, H2L1 LIGO-G060260-00-Z

9. Efficiency vs Livetime • Rate ~ 1 / (T * NL10s) • T = livetime (AKA observation time). • NL10s ~ Int(efficiency * source distribution) • Selection of science segments (including ~ long duration data quality flags) determines livetime. • Shorter duration data quality flags, as well as cuts, event vetoes, etc, produce inefficiency. Eg, SNR threshold cut produces falloff of efficiency vs effective distance. • Because of cuts and signal consistency vetoes, efficiency < 100% for short effective distance. • Some “intermediate duration” DQ flags cause inefficiency to be 10% or more even for nearby sources. • Would prefer to see this counted as loss of livetime. • Issue only for presentation; upper limit calculation shouldn’t depend on how this is reported. • Work in progress / review. LIGO-G060260-00-Z

10. Astrophysical upper limit • To determine number of sources (in MWEG or L10), convolute efficiency with source model • Convolution is in 3-dim space: deffLHO , deffLLO , Mch • Reduced to 2D: dchLHO , dchLLO • Makes it easier to convolute with different source models • Not easily generalized to more detector sites, more important parameters (spin), etc.. Works for now. LIGO-G060260-00-Z

11. Follow-up of loudest triggers LIGO-G060260-00-Z

12. Summary • Hope to wrap up S3/S4 BNS/MACHO/BBH analyses and review by August meeting. • Move on to new analyses and features ASAP • spinning BBH • ringdowns • S5 analyses • detection candidate followup • coherent analysis • parameter estimation • Inspiral/Merger/Ringdown • tests of GR • etc… LIGO-G060260-00-Z