ItineraryGravitational WavesLaser InterferometersAntenna Pattern of a Laser InterferometerLIGO Sensitivity, Science Runs S1 through S5Slide 7The Gravitational Wave Signal TableauRecent Progress in Simulating Binary MergersSlide 10Slide 11Slide 12Gravitational Wave Emission from Stellar Core CollapseAxisymmetric Simulations of Stellar Core CollapseCore Oscillations & Acoustic Waves in Stellar Core CollapseGravitational Waves from Ott et al. SimulationGravitational Waves from Burrows et al. SimulationSlide 18Slide 19Signal Detection MethodsIllustration of Matched FilteringOptimal Matched Filtering for Short SignalsSlide 23Demodulation / Matched Filtering for Continuous-Wave SignalsSlide 25“Excess Power” Search MethodsSlide 27Cross-Correlation MethodsSlide 29Slide 30Variable Data QualityNon-Stationary Noise / GlitchesSlide 33Are We There Yet?A Grand Tour of Gravitational Wave Signals and Detection Methods Peter ShawhanCaltech / LIGOLIGO SeminarMarch 30, 2006LIGO-G060168-00-ZLIGO-G060168-00-Z2Itinerary► Preparing for the trip:Brief review of gravitational waves and detectors► Mapping the territory:An overview of gravitational wave signals► Driving directions:Signal detection methods► Road hazards:Data analysis challenges► The road aheadLIGO-G060168-00-Z3Gravitational WavesEmitted by a massive object, or group of objects, whose shapeor orientation changes rapidly with timeChanges the geometry of space in a time-varying wayStrength and polarization depend on direction relative to source“Plus” polarization “Cross” polarization Circular polarization…Can be a linear combination of polarization componentsLIGO-G060168-00-Z4Laser InterferometersMeasure difference in arm lengths to a fraction of a wavelengthBeam splitterMirrorMirrorPhotodetectorLaserResponds to one polarization componentLIGO-G060168-00-Z5Antenna Pattern of aLaser InterferometerDirectional sensitivity depends on polarization of waves“” polarization “” polarizationRMS sensitivityA broad antenna pattern More like a microphone than a telescopeLIGO-G060168-00-Z6LIGO Sensitivity,Science Runs S1 through S5LIGO-G060168-00-Z7Itinerary► Preparing for the trip:Brief review of gravitational waves and detectors► Mapping the territory:An overview of gravitational wave signals► Driving directions:Signal detection methods► Road hazards:Data analysis challenges► The road aheadLIGO-G060168-00-Z8The Gravitational WaveSignal TableauWaveform knownWaveform unknownShort duration Long durationLow-mass inspiralHigh-mass inspiralBinary mergerh(t)LIGO-G060168-00-Z9 : “lapse function” used in simulation Recent Progress in Simulating Binary MergersFrans Pretorius, PRL 95, 121101 (2005)Succeeded in evolving system through orbit, merger, and ringdownMovies at http://astrogravs.gsfc.nasa.gov/conf/numrel2005/4 : second time derivative of GW strainLIGO-G060168-00-Z10Recent Progress in Simulating Binary MergersCampanelli, Lousto, Marronetti, & Zlochower, PRL 96, 111101 (2006)Different numerical techniques compared to PretoriusMovie at http://www.aip.org/mgr/png/images/bhmergermovie.mpgLIGO-G060168-00-Z11Recent Progress in Simulating Binary MergersBaker, Centrella, Choi, Koppitz, & van Meter, PRL 96, 111102 (2006)Similar approach and results to Campanelli et al.LIGO-G060168-00-Z12The Gravitational WaveSignal TableauWaveform knownWaveform unknownShort duration Long durationLow-mass inspiralHigh-mass inspiralBinary mergerNS / BH ringdown Stellar core collapseLIGO-G060168-00-Z13Gravitational Wave Emissionfrom Stellar Core CollapseGravitational wave emission requires an aspherical collapseIn-falling material can drive oscillation modes of coreCentrifugal forces from rotation can lead to a pole-equator differenceRotational instability can break axisymmetry spontaneouslyLIGO-G060168-00-Z14Axisymmetric Simulations ofStellar Core CollapseZwerger and Müller, Astron. Astrophys. 320, 209 (1997)Ott, Burrows, Livne, and Walder, ApJ 600, 834 (2004)LIGO-G060168-00-Z15Core Oscillations & Acoustic Wavesin Stellar Core CollapseBurrows, Livne, Dessart, Ott, and Murphy, ApJ 640, 878 (2006)Also: http://www.nsf.gov/news/news_summ.jsp?cntn_id=105798&org=NSFAxisymmetric simulation with non-rotating progenitorObserve that in-falling material eventually drives oscillations of the coreAcoustic waves carry energy to outer mantle, driving explosionLIGO-G060168-00-Z16Gravitational Waves fromOtt et al. SimulationPowerPoint slides and movies posted athttp://zenith.as.arizona.edu/~burrows/briley/Suggests that total powerradiated in gravitationalwaves can be huge!LIGO-G060168-00-Z17Gravitational Waves fromBurrows et al. SimulationLIGO-G060168-00-Z18The Gravitational WaveSignal TableauWaveform knownWaveform unknownShort duration Long durationLow-mass inspiralAsymmetric spinning NSHigh-mass inspiralBinary mergerNS / BH ringdown Cosmic string cusp / kinkStellar core collapseCosmological stochastic backgroundMany overlapping signalsRotational instability??? ??? ???LIGO-G060168-00-Z19Itinerary► Preparing for the trip:Brief review of gravitational waves and detectors► Mapping the territory:An overview of gravitational wave signals► Driving directions:Signal detection methods► Road hazards:Data analysis challenges► The road aheadLIGO-G060168-00-Z20Signal Detection MethodsWaveform knownWaveform unknownShort duration Long durationLow-mass inspiralAsymmetric spinning NSHigh-mass inspiralNS / BH ringdown Cosmic string cusp / kinkStellar core collapseCosmological stochastic backgroundMany overlapping signalsRotational instability??? ??? ???Matched filteringBinary mergerLIGO-G060168-00-Z21Illustration of Matched FilteringLIGO-G060168-00-Z22Optimal Matched Filteringfor Short SignalsLook for maxima of |z(t)| abovesome threshold  triggerdfefSfhfstztfin20*)()(~)(~4)(Noise power spectral densityTemplateDataUse a bank of templates to coverparameter space of target signalsInspirals withM < m1,m2 < 3 MMin. match = 0.97LIGO-G060168-00-Z23Signal Detection MethodsWaveform knownWaveform unknownShort duration Long durationLow-mass inspiralAsymmetric spinning NSHigh-mass inspiralNS / BH ringdown Cosmic string cusp / kinkStellar core collapseCosmological stochastic backgroundMany overlapping signalsRotational instability??? ??? ???Matched filteringSemi-coherent demodulationDemodulationApprox. filteringBinary mergerLIGO-G060168-00-Z24Demodulation / Matched Filtering for Continuous-Wave SignalsEven a “continuous”