Closing in on a Short-Hard Burst Progenitor Constraints from Early-Time Optical Imaging and(28)

The localization of the short-duration, hard-spectrum GRB 050509b was a watershed event. Thanks to the nearly immediate relay of the GRB position by Swift, we began imaging the GRB field 8 minutes after the burst and continued for the following 8 days. No

NNG05GF35G;heisalsogratefulforaMillerResearchProfessorshipatU.C.Berkeley,duringwhichpartofthisworkwascompleted.S.S.issupportedbytheCenterforGravitationalWavePhysicsfundedbytheNSFundercooperativeagreementPHY01-14375,andbyNSFgrantPHY02-03046.D.P.andE.R.-R.gratefullyacknowledgesupportprovidedbyNASAthroughChandraPostdoctoralFellowshipgrantnumbersPF4-50035andPF3-40028(respectively),awardedbytheChandraX-rayCenter,whichisoperatedbytheSmithsonianAstrophysicalObservatoryforNASAundercontractNAS8-03060.S.J.gratefullyacknowledgessupportviaaMillerResearchFellowshipatU.C.Berkeley.J.N.acknowledgessupportfromNASAthroughHubbleFellowshipgrantHST-HF-01165.01awardedbytheSpaceTelescopeScienceInstitute,whichisoperatedbytheAssociationofUniversitiesforResearchinAstronomy,Inc.,undercontractNAS5-26555.TheresearchofJ.G.issupportedbytheUSDepartmentofEnergyundercontractnumberDE-AC03-76SF00515.ThispublicationmakesuseofdataproductsfromtheTwoMicronAllSkySurvey,whichisajointprojectoftheUniversityofMassachusettsandtheInfraredProcessingandAnalysisCenter/CaliforniaInstituteofTechnology,fundedbytheNationalAeronauticsandSpaceAdministrationandtheNationalScienceFoundation.SomeofthedatapresentedhereinwereobtainedattheW.M.KeckObservatory,whichisoperatedasascienti cpartnershipamongtheCaliforniaInstituteofTechnology,theUniversityofCalifornia,andNASA;theObservatorywasmadepossiblebythegenerous nancialsupportoftheW.M.KeckFoundation.TheanalysispipelineusedtoreducetheDEIMOSdatawasdevelopedatU.C.BerkeleywithsupportfromNSFgrantAST-0071048.BasedonobservationsobtainedattheGeminiObservatory,whichisoperatedbytheAssociationofUniversitiesforResearchinAstronomy,Inc.,underacooperativeagreementwiththeNSFonbehalfoftheGeminipartnership:theNationalScienceFoundation(UnitedStates),theParticlePhysicsandAstronomyResearchCouncil(UnitedKingdom),theNationalResearchCouncil(Canada),CONICYT(Chile),theAustralianResearchCouncil(Australia),CNPq(Brazil)andCONICET(Argentina).Finally,wewishtoextendspecialthankstothoseofHawaiianancestryonwhosesacredmountainweareprivilegedtobeguests.