天体物理学报：LIGO引力波探测器释疑

LIGO:InitiatingtheAdvancedDetectorEraforGravitationalWaveAstrophysics,AlbertLazzariniDeputyDirector,LIGOLaboratoryCaliforniaInstituteofTechnologyOnbehalfoftheLIGOScientificCollaboration13October2014EasternForumofScienceandTechnology(EFST)Shanghai,China,CollidingBlackHolescourtesyofNCSA,Outline,TheLIGOmissionGravitationalwavesandtheirdetectionAstronomicalsourcesforLIGOTheAdvancedLIGOProjectProspectsforaglobalnetwork,EFST,Shanghai,China13October2014,LIGO-G1401149-v1,LIGOAddressesFundamentalQuestionsinPhysicsandAstronomy,LIGOLaboratoryistheworldsleadingfacilityforconductinggravitational-wavescienceTheLIGOScientificCollaborationisthescientificorganizationthat,inconcertwiththeLIGOLaboratory,carriesoutLIGOscienceFundamentalPhysicsIsGeneralRelativitythecorrecttheoryofgravity?Wavepropagationspeed(delaysinarrivaltimeofbursts)Spincharacteroftheradiationfield(polarizationofradiationfromCWsources)Areblackholesreallycharacterizedbyonlymassandspin?Howdoesmatterbehaveunderextremeconditions?Astrophysics,Astronomy,CosmologyDocompactbinarymergerscauseGRBs?Whatisthesupernovamechanismincore-collapseofmassivestars?Howmanylowmassblackholesarethereintheuniverse?Dointermediatemassblackholesexist?Howbumpyareneutronstars?Canweobservepopulationsofweakgravitationalwavesources?Canbinaryinspiralsbeusedas“standardsirens”tomeasurethelocalHubbleparameter?,LIGO-G1401149-v1,EFST,Shanghai,China13Octonber2014,Credit:LIGOScientificCollaboration,GWUpperlimitmap,LIGO-G1401149-v1,EFST,Shanghai,China13October2014,LIGO-G1401149-v1,TheLIGOScientificCollaboration,80groups,900+peopleworkingontechnologyforLIGOdetectorsandlookingattheLIGO/GEOdata.JointlyoperatingwithVirgoCollaborationsVirgodetector,AlbertEinstein,TheSpecialTheoryofRelativity(1905)overthrewcommonsenseassumptionsaboutspaceandtimeFinitepropagationofinformationElectromagneticradiationTheGeneralTheoryofRelativityandtheoryofGravity(1916)Gravitydescribedasawarpageofspacetime,notaforceactingatadistanceFinitepropagationofinfluenceofgravityGravitationalradiation,EFST,Shanghai,China13October2014,LIGO-G1401149-v1,Existenceproof:PSR1913+16,Awarded1974NobelPrizeinPhysics,EFST,Shanghai,China13October2014,LIGO-G1401149-v1,forbitaltoday0.000035Hz(35microHertz)forbital300,000,000yrs100Hz(inLIGOband),GravitationalWaves,Gravitationalwavesarepropagatingdynamicfluctuationsinthecurvatureofspace-time(ripplesinspace-time)Physicalproperties:predictedtotravelatthespeedoflightalmosttransparenttomatterquadrupoleradiationLIGOtargets:astrophysicalobjectsmovingatspeedapproachingthespeedoflightGravitationalwaveamplitudesarestrains:Senseofscale:computedstrainfromabinaryneutronstarpairM=1.4M,r=5x1023m(15Mpc),Rsep=40km,forb380Hz,v/c0.3,LIGO-G1401149-v1,EFST,Shanghai,China13October2014,LIGO-G1401149-v1,LIGOInterferometry,LIGOusesenhancedMichelsoninterferometrysuspended(freelyfalling)mirrorsPassingGWsstretchandcompressthedistancebetweentheendtestmassandthebeamsplitterTheinterferometeractsasatransducer,turningGWsintophotocurrentproportionaldifferentialarmlengthAcoherentstrain-amplitudedetector,AdvancedLIGO,4km,LIGO-G1401149-v1,EFST,Shanghai,China13October2014,TheLIGOLaboratorySites,Interferometersarealignedalongthegreatcircleconnectingthesites,EFST,Shanghai,China13October2014,LIGO-G1401149-v1,Hanford,WA-,45Mpc),EFST,Shanghai,China13October2014,LIGO-G1401149-v1,LIGOAstrophysics,Firstgenerationobservations:SciencerunsS1S6Spanningtheepoch20022010Currentlyupgradinginterferometersto2ndgenerationadvanceddetectorsTodate,nodetectionshavebeenmade80+publicationsonupperlimitstodateSee:/ppcomm/Papers.htmlAfewhighlightsfollow,EFST,Shanghai,China13October2014,LIGO-G1401149-v1,BinaryCoalescencesS5/S6all-skyblindsearchTightestratelimitsfromLIGOObservations,Inferredtheoreticalratesbasedonbinarypulsars,populationsynthesis,Ref:arXiv:1111.7314v4,EFST,Shanghai,China13October2014,LIGO-G1401149-v1,Still10Xfromoptimisticrates,100XfromrealisticratesNeedtoawaitnextgenerationdetectorAdvancedLIGO,D6500light-yearsYoungandrapidlyspinningdownSpinfrequencynEM=29.8HznGW=2nEM=59.6HzSpindowndueto:electromagneticbraking?particleacceleration?GWemission?ObservedluminosityoftheCrabnebulaaccountsfor1/2spindownpowerS6results:Astrophys.J.785(2014)119h1.6x10-259XbelowtheEMspindownlimit(usingrestrictedpriorsonorientation)GWenergyupperlimit:1.2%ofradiatedenergyisinGWsEllipticityupperlimit:e8.6x10-5,ScienceHighlight:BeatingtheCrabPulsarSpinDownLimit,EFST,Shanghai,China13October2014,LIGO-G1401149-v1,TimelapsemovieofCrabNebulabyChandraX-rayObservatoryCredit:NASA/CXC/ASU/J.Hesteretal.,EFST,Shanghai,China13October2014,AdvancedLIGO:A2ndgenerationdetector,10XbetteramplitudesensitivityEventrate(reach)31000Xgreater1dayofobservationwithAdvancedLIGO1yearwithInitialLIGO!,LIGO-G1401149-v1,AdvancedLIGOUpgrade,CompleteupgradeofallLIGOinterferometersto2ndgenerationdesignsTakeadvantageofnewtechnologiesandR200WforAdvancedLIGOContributedbyLaserZentrumHannover,Recentsnapshotofinterferometerperformance-LLO,EFST,Shanghai,China13October2014,LIGO-G1401149-v1,Recentrangefor1.4M+1.4McoalescingNSbinaries(SNR=8):36Mpc(117millionlight-years)After4monthsofcommissioning,almost2XbetterthanbestperformancewithinitialLIGO(20Mpc),EFST,Shanghai,China13October2014,LIGO-G1401149-v1,OperatedasaphasedarrayaperturesynthesisGWastronomy:-Enhancedetectionconfidence-Localizesources-Decomposethepolarizationofgravitationalwaves,GrowingInternationalNetworkofGWInterferometers,LIGO-India:4kmAdvancedLIGOProposedConceptUndercurrentconsideration,Localization:InternationalArrayofGWInterferometers,Exploittime-of-arrivaldifferences,dtij,totriangulatesourcedirection,GlobalarrayofinterferometricGWdetectors,EFST,Shanghai,China13October2014,LIGO-G1401149-v1,Summary,GravitationalwavesareanoutcomeofrelativistictheoryofgravityTheypropagateessentiallyundisturbedacrosstheentireuniverseTheycanprobematteratextremelyhighdensitiesandhigh-fieldgravityinregionsthatcannotbeotherwiseobservedTheycomplementEMobservationsTheinitialerainterferometerspavedthewayinourunderstandinghowtoanalyzestraindatatolookforgravitationalwavesfromabroadclassofsourcesnodetectionsyet.AnchoredbyAdvancedLIGO,theGWcommunityisworkingtobuildaglobalnetworkofkm-scaledetectorstoperformsynthetic-apertureGWastronomyTheLIGOScientificCollaborationisnowalargeinternationalorganizationOpencollaborationnewgroupsarewelcometojoin,EFST,Shanghai,China13October2014,LIGO-G1401149-v1,EFST,Shanghai,China13October2014,LIGO-G1401149-v1,AnchoredbyAdvancedLIGO,globalGWnetworkwillgiveusanewwayofobservingtheuniverse,GWs?,EFST,Shanghai,China13October2014,LIGO-G1401149-v1,4kmWashington+4kmLousiana+4kmIndia+3kmItaly,SkyLocalizationErrorEllipsesLIGO+Virgo(inItaly),S.Fairhurst2011,2x4kmWashington+4kmLousiana+3kmItaly,LIGOsmission,LIGOistheworldsleadingfacilityforconductinggravitational-wavescience.LIGOsmissionis:AdvancedLIGOconstructtheAdvancedLIGOinterferometersandbringthemtodesignsensitivityPhysics/Astrophysics-directdetectionofgravitationalwavesanddevelopmentofgravitational-waveastronomyPrecisioninterferometry-developmentofinstrumentscienceR&DtoupgradeandimproveAdvancedLIGOFacilities-operateandmaintaintheLIGOObservatoriesandcampusfacilitiesOutreachdevelopscientificeducationandpublicoutreachrelatedtogravitationalwaveastronomyGlobalnetworkdeveloptheinternationalgravitationalwavecommunitytocoordinategravitationalwaveobservations.TheLIGOScientificCollaborationisthescientificorganizationthat,inconcertwiththeLIGOLaboratory,carriesoutLIGOscience,LIGO-G1401149-v1,LIGOAddressesFundamentalQuestionsinPhysicsandAstronomy,FundamentalPhysicsIsGeneralRelativitythecorrecttheoryofgravity?Wavepropagationspeed(delaysinarrivaltimeofbursts)Spincharacteroftheradiationfield(polarizationofradiationfromCWsources)Areblackholesreallycharacterizedbyonlymassandspin?Howdoesmatterbehaveunderextremeconditions?Astrophysics,Astronomy,CosmologyDocompactbinarymergerscauseGRBs?Whatisthesupernovamechanismincore-collapseofmassivestars?Howmanylowmassblackholesarethereintheuniverse?Dointermediatemassblackholesexist?Howbumpyareneutronstars?Canweobservepopulationsofweakgravitationalwavesources?Canbinaryinspiralsbeusedas“standardsirens”tomeasurethelocalHubbleparameter?,LIGO-G1401149-v1,Credit:LIGOScientificCollaboration,GWUpperlimitmap,G14XXXXX-v1,Aninterferometerisreallyamicrophone,Sensitivitydependsonpropagationdirection,polarization“”polarization“”polarizationRMSsensitivity2:1ratiobetweenequatorandpolesessentiallyisotropicSourcelocalizationreliesontime-of-flightinformationanddetailsofwaveformfrommultiplesites,EFST,Shanghai,China13October2014,LIGO-G1401149-v1,Howtomakeaverysensiti