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Vasileiadis George LUMP/Un. Montpellier II

Recent results of the High Energy Stereoscopic System (H.E.S.S.). Vasileiadis George LUMP/Un. Montpellier II. for the H.E.S.S. Collaboration. Outline. Instruments for gamma-ray astronomy H.E.S.S. instrument and physics program Selected recent discoveries. ➢ ➢ ➢. Galactic sources

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Vasileiadis George LUMP/Un. Montpellier II

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  1. RecentresultsoftheHighEnergy StereoscopicSystem(H.E.S.S.) Vasileiadis George LUMP/Un. Montpellier II fortheH.E.S.S.Collaboration

  2. Outline Instrumentsforgamma-rayastronomy H.E.S.S.instrumentandphysics program Selectedrecentdiscoveries ➢ ➢ ➢ Galacticsources Novelsources ➢ ➢ Fundamentalphysics: ➢ Searchfordarkmatter TestsofLorentzinvariance ➢ ➢

  3. Gamma-rayastronomy Goal:studytheuniverseintheGeV-TeVenergyrange non-thermalemission revealcosmicaccelerators twomainemissionmechanisms: ➢ ➢ ➢ p0decay(“hadronic”) inverseComptonscatteringof electrons(“leptonic”) ➢ ➢ • p3

  4. Instrumentsfor gamma-rayastronomy

  5. Comparisonofthedetectionmethodsingamma-rayastronomy satellite-based ground-based Cherenkovtelescopes high-altitudearrays D.Nedbal NASA Milagro e.g.H.E.S.S.,MAGIC,VERITAS detectCherenkovlight fromgamma-rayinduced airshowers e.g.Milagro,HAWC, TibetASg,ARGO-YBJ detectchargedparticles intailsofgamma-ray inducedairshowers e.g.EGRET,Fermi directdetectioninspace e.g.Fermi-LAT: Sitrackerwith conversionfoils+ EMcalorimeter • p5

  6. Comparisonofthedetectionmethodsingamma-rayastronomy ground-based high-altitudearrays e.g.Milagro,HAWC, TibetASg,ARGO-YBJ detectchargedparticles intailsofgamma-ray inducedairshowers Cherenkovtelescopes e.g.H.E.S.S.,MAGIC,VERITAS detectCherenkovlight fromgamma-rayinduced airshowers D.Nedbal Milagro 300GeVgamma-ray • p6

  7. Comparisonofthedetectionmethodsingamma-rayastronomy satellite-based ground-based Cherenkovtelescopes high-altitudearrays D.Nedbal NASA Milagro lowenergythreshold highsensitivity largeaperture,highduty cycle Energyrange Area Energyresolution Angularresolution Backgroundsuppression Aperture Dutycycle 0.1-300GeV 1m2 10%@1GeV 0.7°@1GeV >99.99% 2.4sr >90% 0.05–50TeV 100000m2 15% 0.05° 99% 0.006sr ~10% 0.1–100TeV 30000m2 ~50% 0.3°-0.7° >95% >2sr >90% followingGusSinnis,CTAworkshop,Paris,March2007 unbiasedskysurvey, transients<100GeV extendedsources unbiasedskysurvey extendedsources transients high-resolutionspectra detailedmorphologicalanalysis surveycapabilityforlimitedsky region • p7

  8. Gamma-rayastronomywithIACTs IACT=ImagingatmosphericCherenkovtelescope KonradBernlöhr • p8

  9. H.E.S.S. arrayoffourimaging atmosphericCherenkov telescopes locatedintheKhomas highlandsofNamibia,at 1800mASL Eth=~100GeV DE/E=15% angularresolution~0.1° 5°FoV ➢ ➢ ➢ ➢ ➢ ➢ • p9

  10. H.E.S.S.physicsprogram Extendedextragalacticobjects SNRPP AGN Survey starburstgalaxies galaxyclusters pairhalos SNRs PWNe Plerions Binaries radiogalaxies GRBs Astroparticle/Exotic ADC,GSFC GalacticPlaneSurveyand follow-upobservations GalacticCenter Multiwavelength Cosmicrays Darkmatter Lorentzinvariancetests milleniumsimulation SlidefollowingM.Daniel,withmaterialfromNASA/ESA • p10

  11. Galacticsources

  12. GalacticPlaneSurvey largeFoVenablessystematicscan ofInnerGalaxy,ongoingsince 2004 aim:discoveryofnewgamma-ray sources over60GalacticVHEgamma-ray sources populationdominatedbySNRs, PWNe,unidentifiedsources focusin2011: ➢ ➢ ➢ ➢ ➢ 2300hofgood-qualitydata dataset=pointedobservations+ scanmode+hotspotfollow-up ➢ ➢ sensitivitygoalof2%Crab forcoreregion deepeningexposureinouter Galaxy ➢ ➢ point-sourcesensitivity(G=2.5)for5sdetection,atlatitudeb=-0.3° H.Gastetal.,proc. 32ndICRC(2011) • p12

  13. Shell-typesupernovaremnants:HESSJ1731-347 H.E.S.S.collaboration, A&Ainpress HESSJ1731-347 HESSJ1729-345 Firstnon-thermalshellSNR discoveredbasedongamma- rayobservations! TeVandMWLdatacanbe explainedineitherhadronicor leptonicscenario. ➢ ➢ RX J1713.7-3946 • RCW86 VelaJr SN1006 • p14

  14. possibleinteractionofSNRwithamolecularcloud G318.2+0.1: VHEgamma-rayemission foundinGalacticplane survey COdata:molecularcloud ➢ ➢ ➢ (~106Msun)foundateither 3.5or9.2kpc Assumingnearsolutionand Whiteoak&Green1996 G318.2+0.1in VHEgamma-rays 843MHzradioimage G318.2+0.1 ➢ n~1/cm3:age~8000years: Sedovphase Possiblescenario: emissionfromcosmicrays acceleratedintheSNRand illuminatingtheMC ➢ COradiodata(Dameetal.,2001) P.Hofverbergetal., arXiv:1104.5119 • p15

  15. Novelsources

  16. Starburstgalaxies Stronglyenhanced star-formationratei.e. highsupernovarate Consequence:high cosmicray(CR) density ➢ ➢ Highgasdensity Intenseradiationfields Promisingconditions forgamma-ray production ➢ ➢ ➢ stellarnurseries interestingtestof standardparadigmfor cosmic-rayproduction StarburstgalaxyNGC253(optical) ESO • p17

  17. StarburstgalaxyNGC253 H.E.S.S.collaboration,Science326(2009)1080-1082 119hoursofgoodobservations advancedimageanalysistechniques integralfluxroughly0.3%Crab:one ofthefaintestsourcesdetectedsofar inVHEgammarays Point-likeemission,consistentwith ➢ ➢ ➢ ➢ starburstnucleus x-ray VHEgamma-ray optical • p18

  18. StarburstgalaxyNGC253 Hadronicscenario:TeVcosmic- raydensityinthestarburstregion aboutthreeordersofmagnitude largerthanatthelocationofthe Earth About5%oftheenergyinCRs convertedintogammarays VeritasdetectionofM82,Fermi detectionofNGC253andM82 F.Aceroetal., Science326(2009)1080 ➢ ➢ ➢ starburst galaxies emerging as new source class in gamma-ray astronomy • p19

  19. Terzan5 near-IRimageofTerzan5 40arcsec GlobularclusterTerzan5: largestpopulationofidentified millisecondpulsarsandhighstellar densityatitscore electronsacceleratedbymillisecond pulsarsthemselvesorintheircolliding winds intensestellarradiationfield integralVHEgamma-rayfluxmatches Predictions Few possibilities as of the origin of this VHE source under discussion. ! First time observed H.E.S.S.collaboration, A&A531(2011)L18 ➢ ➢ ➢ ➢ ➢ ➢ ESO • p20

  20. Fundamentalphysics

  21. The Dark Matter of the Universe In Standard Cosmology Cold Dark Matter is favoured Weakly Interacting Massive Particles (WIMPs) WIMPs must be beyond the StandardModel Many experimentsare trying/projected to find WIMPs: · DIRECTLY: collision with ordinary matter in dedicated underground experiments. [DAMA, GENIUS, CDMS, CRESST, ...] · INDIRECTLY: Annihilation processes producing antiprotons, e+, , . [AMS, Neutrino Telescopes, GLAST, Cherenkov Telescopes] BUT... No confirmed detection yet.

  22. Where to look for Cold Dark Matter in our neibourghood ? WIMPs wouldconstitute the galactic halo and would concentrate at - the galaxy center - dark matter clumps - visible satellites - invisible satellites - nearby galaxies (M31)

  23. SearchforDarkMatter gamma-rayfluxfromdarkmatterannihilations: ➢ AldeeCharbonnier AldeeCharbonnier DMdensityprofilesoftheGalactichalo annihilationspectrafordifferentWIMPmodels • p23

  24. Recentresultsofindirectdarkmattersearch compilationoflimitsforneutralinoLSP AldeeCharbonnier GalacticCenterHalo -|b|>0.3°toexclude astrophysicalbackgrounds dwarfgalaxies systemsdominatedbydark matter ➢ ➢ -rsource>rbg-region BestH.E.S.S.limitscurrentlyintherange 3x10-25 to3x10-24 cm3s-1. H.E.S.S.Collaboration, PRL106(2011)161301 Astropart.Phys.34(2011)608 ApJ735(2011)12 • p24

  25. Energy dependence of the Speed of light • Space-time at large distances is “smooth” but, if Gravity is a quantum theory, at very short distances it might show a very complex ( “foamy” ) structure due to Quantum fluctuations. • A consequence of these fluctuations is the fact that the speed of light in vacuum becomes energy dependent. • The energy scale at which gravity is expected to behave as a quantum theory is the Planck Mass • EQG = O(MP )= O(1019) GeV

  26. TestofLorentzinvariance • In addition one needs very fast transient phenomena providing a “time stamp” for the “simultaneous” emission of different energy g –rays. • Good source candidates are: • - Very distant Blazars showing fast flares • - Gamma-Ray-Bursts (GBR) • Usepulse-shapeofgiantAGNflare,tosearchforenergy-dependentvelocity ofgamma-rayphotons.Idealcandidate:PKS2155flareofJuly28th,2006. • Lightcurveforlowenergyrange(0.25-0.28TeV)astemporaltemplate. • NohintforLorentzinvarianceviolationfound.95%CLupperlimits: • MlQG>2.1 1018GeVMqQG> 6.4 1010GeV NASA • p25

  27. H.E.S.S.II lowerthresholdto~50GeV: ➢ pulsarphysics AGNphysics darkmattersearch overlapwithFermi-LATenergyrange ➢ ➢ ➢ ➢ ontrackforfirstlightinJune2012 ➢ • p29

  28. H.E.S.S.II • p28

  29. Summary TeVgamma-rayastronomyhasturned intoamaturefield,withover120 sourcesknowntodate. ➢ H.E.S.S.GalacticPlaneSurveycontinues discoveringnewsources. Novelsourceclassescanstillbe discovered. Importantcontributionstofundamental physics. H.E.S.S.-Imirrorrefurbishmentsin progress.H.E.S.S.-IInearingcompletion, firstlightforeseeninJune2012. ➢ ➢ ➢ ➢ • p30

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