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PRESENT AND FUTURE DARK MATTER SEARCHES WITH I MAGING A TMOSPHERIC C HERENKOV T ELESCOPES

PRESENT AND FUTURE DARK MATTER SEARCHES WITH I MAGING A TMOSPHERIC C HERENKOV T ELESCOPES. J-F. Glicenstein IRFU, CEA- Saclay. Outline. Imaging Atmospheric Cherenkov Telescopes Indirect dark matter searches with IACT Results on the Galactic Halo (H.E.S.S)

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PRESENT AND FUTURE DARK MATTER SEARCHES WITH I MAGING A TMOSPHERIC C HERENKOV T ELESCOPES

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  1. PRESENT AND FUTUREDARK MATTER SEARCHES WITHIMAGING ATMOSPHERIC CHERENKOV TELESCOPES J-F. Glicenstein IRFU, CEA-Saclay

  2. Outline • Imaging Atmospheric Cherenkov Telescopes • Indirect dark matter searches with IACT • Results on the Galactic Halo (H.E.S.S) • Dwarf Galaxies: Segue (MAGIC, VERITAS) • Galaxy clusters: Fornax (H.E.S.S) • Dark matter searches with CTA

  3. VERITAS MAGIC H.E.S.S. Major Active IACTs

  4. HighEnergyStereoscopicSystem located in Namibia, latitude=-23o, altitude=1800 m 4 telescopes, 107 m2each cameras 960 PMT FOV= 5o trigger threshold=100GeV installed: january 2004 installation of 5thtelescope in 2011, first light expected 2012 mirror: 600m2, 2048 PMT, FOV=3.5o, trigger threshold=20 GeV

  5. MajorAtmosphericGamma-ray Imaging Cherenkov located in La Palma (Canaries Islands), latitude=+29o, altitude=2225 m mirror: 234 m2 camera 534 PMT FOV=3.5o trigger threshold=60 GeV installedlate 2004 installation 2ndtelescope in 2009 mirror 234m2, 1099 PMT

  6. VeryEnergeticRadiationImaging TelescopeArraySystem origin: Whipple collaboration (10 m, late 80s) located in Arizona,latitude=+32o, altitude=1275 m 4 telescopes, 106 m2each cameras 499 PMT FOV=3.5o trigger threshold=100 GeV installed in april 2007

  7. Gamma- ray Particle shower ~ 10 km ~ 1o Cherenkov light ~ 120 m 2 4  3 1 Imaging atmospheric Cherenkov telescopes • brief flash ~3 ns • steroscopy: cosmic ray background rejection improved gamma ray reconstruction

  8. VHE gamma-ray astronomy: catalog of sources The VHE gamma-ray sky(November 2011) http://www.mppmu.mpg.de/~rwagner/sources/ ~100 sources (60 galactic) Present and future DM searches with IACT

  9. Indirect DM searches with IACTs WIMP annihilation flux into g rays observed by an IACT: particle model fAP: dark halo model • Most currentparticlemodels: • neutralinos (MSSM) • U Extra Dimensions (Servant, Tait 2003) boson B • leptophilicmodels (PAMELA excess) • decayingdarkmatter • Astrophysical factor: •  dense targets • GalacticCenter • nearbydwarf galaxies, globular clusters • galaxyclusters (Fornax) • darkmatterclumps Present and future DM searches with IACT

  10. Signal boosts: particle physics • Sommerfeld effect: • effective lowvelocity dispersions • resonancesat: • InternalBrehmstrahlung • annihilation to W+W-,ff (cheavyhiggsino-like) relative velocityb FSR IB Present and future DM searches with IACT

  11. Signal boosts: astrophysics • Boost effect B from unresolved DM clumps • estimated with Aquarius simulation (Springel et al 2008) • B sensitive the assumed value of Mlim ( Mlim-0.226) • B ~ (a few) for point-like searches towards dwarf galaxies • B up to 2 order of mag. for extended searches (galaxy clusters) Mlim = 10-6 M ⊙ Mlim = 5 10-3 M ⊙ Fornax galaxy cluster Present and future DM searches with IACT

  12. HESS searches towards the Galactic halo • 112 hours collected (2004-2008) • 1 degree around GC • galactic plane (|b| < 0.3o) excluded • background estimated by reflected bakground technique Present and future DM searches with IACT

  13. H.E.S.S. limits on WIMP annihilation in the Galactic halo Excluded 95% C.L. mSUGRA models A.Abramovski et al. (HESS), Phys.Rev.Lett 106, 161301 (2011) Present and future DM searches with IACT

  14. UMi Draco Same (Woods et al) DM halo modelling M15 (adiabatic compression) MSSM + WMAP constraints Searches towards globular clusters: M15 WHIPPLE HESS limit Excluded (95% CL) • very small 0.04 pc core • low metalicity • (“primordial”) • not dominated by DM • Woods et al (Whipple) 2008: constraints at the 10-23 level (1.2 hour!) • A.Abramovski et al (HESS) ApJ 735 11 (2011): also at 10-23 level (15.2 h) • takes into account heating of DM by stars in GC core Present and future DM searches with IACT

  15. Dwarf spheroidal galaxies • dark matter dominated • mass range: 107-109 M ⊙ • observed by IACTs: • Sagittarius, Carina, • Sculptor, Draco,Willman1, • Segue1, Umin, Canis Major, • Boötes 1 Walker et al 2007 Belokurov et al 2006 • data on surface brightness, • velocity dispersion, globular clusters, • colors  galactic structure well • modeled Present and future DM searches with IACT

  16. Segue 1 dwarf galaxy GC dwarf galaxies MV log (core radius) • discovered 2006 in the SEGUE (Sloan) catalog by Belokurov et al. • located 23±2 kpc from the Sun • located at the intersection of Saggitarius and Orphan stellar streams • unclear whether dwarf galaxy or globular cluster • only 71 stars resolved. • velocity dispersion s=3.7±1.5 km/s M = 5.8 106 M⊙ • seems dominated by DM, but error on mass ~ 100% Present and future DM searches with IACT

  17. MAGIC observations of Segue1 dwarf Emin = 100 GeV • single telescope observations (MAGIC1), taken in 2008-2009 • ~ 29.5 h good data • no evidence for signal • Segue 1 dwarf model was modelled as an Einasto profile (Essig et al 2010) • analysis in a slightly extended region |a|< 0.14o (DW = 10-5sr) • J(DW) = 1.78 1019 GeV5/cm2sr Present and future DM searches with IACT

  18. MAGIC searches towards Segue1: MSUGRA exclusion Excluded 95% C.L. 2 s errors on J(DW) (uncertainty on M) <sv>min ~ 10-23 cm3s-1 ( cct+t-) J.Aleksic et al. (MAGIC), JCAP 06 035(2011) Present and future DM searches with IACT

  19. VERITAS observations of Segue 1 dwarf -”contamination” by bright star(h-Leonis) -removed from background evaluation -Emin = 300 GeV -Significance of signal inside q<0.12o: 1.4 s target • 48.7 hours obtained in 2010 and 2011 • no evidence for signal • same Einasto profile than the MAGIC paper • analysis in region q < 0.12o • J(DW) = 7.7 1018 GeV5/cm2sr Present and future DM searches with IACT

  20. VERITAS searches towards Segue 1: exclusion limits Excluded 95% C.L. <sv> min ~ 2 10-24 cm3 s-1 (cct+t-) <sv> from thermal models E.Aliu et al (VERITAS), PRD 85, 062001 (2012) Present and future DM searches with IACT

  21. VERITAS searches towards Segue 1: boosts Excluded 95% C.L. <sv> from thermal models Wino-like neutralino self-annihilation self-annihilation to a 250 GeV particle pair E.Aliu et al (VERITAS), PRD 85, 062001 (2012) Present and future DM searches with IACT

  22. Searches towards Segue 1: leptophilic models MAGIC VERITAS A fraction of parameter space excluded by MAGIC @ low energy and VERITAS @ high energy Present and future DM searches with IACT

  23. Sagittarius dwarf galaxy HESS • recent observations of • Sgr stream allows • better modelling • of Sgr Dwarf (closest dwarf) • update on former HESS limits • by Viana et al (Astroparticle • Physics 2012) old limits CTA • should be detectable with CTA • (Mwimp a few TeV,200 h observation) • However, expected signal from • msecond pulsars in M54 (background) • also detectable at 4-60 s Present and future DM searches with IACT

  24. The Fornax galaxy cluster X rays GC Schuberth et al (2009) • distance d=19 Mpc • central galaxy NGC1399 with a passive SMBH (109 M ⊙) • total mass ~ 1014 M ⊙ , extends over 1 Mpc (6o) • dark matter distribution well studied with X-rays, globular clusters, stars etc • 2 approaches in modelling: • assume NFW profile with concentration param. from virial mass (RB02) • use directly measured profiles Present and future DM searches with IACT

  25. H.E.S.S. observations of the Fornax galaxy cluster • 14.5 hours of data obtained in 2005 • “minimal energy” of observations: Emin = 260 GeV • boost effect expected from substructure  signal in extended regions • signal region: • q < 0.1o, significance S = 2.3 s • q < 0.5o, significance S=1.2s • q< 1o, significance S=0.6s Present and future DM searches with IACT

  26. HESS limits on Fornax: effect of source extension Present and future DM searches with IACT

  27. H.E.S.S. results on Fornax: WIMPs exclusion A. Abramovski et al., arXiv1202.5494 (2012), accepted in ApJ. Present and future DM searches with IACT

  28. H.E.S.S limits on Fornax: KK models Present and future DM searches with IACT

  29. HESS results on Fornax: boost factors Excluded 95% CL Present and future DM searches with IACT

  30. The next generation of IACTs: CTA (2015) 2 arrays: north+south  all-sky coverage corearray 100 GeV-10 TeV 23 ø=12 m telescopes low energy section Ethresh ~ 10 GeV 4 ø=23 m telescopes highenergy section 32 ø=5-6 m tel. on 10 km2 area Present and future DM searches with IACT

  31. Sensitivity of CTA energy range increase x 10 flux sensitivity gain Flux sensitivity for a 50 h observation Present and future DM searches with IACT

  32. Dwarf galaxy searches with CTA Segue 1 Sculptor Several arrays layout studied Low energy High energy Courtesy A. Viana D.Nieto Present and future DM searches with IACT

  33. dwarf galaxies with CTA (2) Boost factor A signal from Willman 1 or Segue 1 may be observable with CTA depending on boost factor. Present and future DM searches with IACT

  34. Galactic plane flux sensitivity (CTA) ~400 hours total 10 hourseachbin • assume Emin = 50 GeV • 500 GeV WIMP annihilating to bb • x10 gain in effective area, x2 gain in hadron rejection • reaches 10-13 cm-2 s-1sensitivity, except on new sources Present and future DM searches with IACT

  35. Searches for clumps HESS sensitivity • clumpsfromViaLacteaII (Diemand, Kuhlen, Madau, 2008) • ~104resolved halos in MW (M>105Msol) • 103randomrealizations (rotate the observer position @8.5 kpc) • 168±44 clumpsinside HESS galacticsurvey Present and future DM searches with IACT

  36. Expected <sv> limits with clumps (galactic plane) Missing one order of mag. to reach thermal<sv> P.Brun, E.Moulin,J.Diemand, J-F.G, PRD 83, 015003 (2011) Present and future DM searches with IACT

  37. Expected <sv> limits with clumps (1/4 sky) • 1/4 survey in ~6 years • assume 5 10-13 cm-2s-1sensitivity (5 hour/bin) • number of subhalos: 3907±324 • thermal WIMPsregionreachable P.Brun, E.Moulin,J.Diemand, J-F.G, PRD 83, 015003 (2011) Present and future DM searches with IACT

  38. Conclusion • Best constraints on <sv> from observation by H.E.S.S of galactic halo • Many observations of dwarf galaxies. Most stringent constraints from observation of Segue 1 (Magic & Veritas) • The limits have important astrophysical systematics (GC vs dwarf galaxies, modelling) • Constraints on DM annihilation in the Fornax cluster (H.E.S.S) competitive with those from dwarf. • With planned array CTA, observations of Segue1, Willman1 reach the thermal annihilation region with proper boost • Searches for clump with CTA may give detections or provide stringent constraints. Present and future DM searches with IACT

  39. Back-up slides Present and future DM searches with IACT

  40. Present and future DM searches with IACT

  41. Present and future DM searches with IACT

  42. Present and future DM searches with IACT

  43. HESS searches towards the Galactic halo Present and future DM searches with IACT

  44. CTA: array design target performances Present and future DM searches with IACT

  45. Expectations for Galactic plane survey Funk,Hinton,Hermann,Digel, arXiV0901.1885 • assumes • x 2 improvement in hadron rejection • x 2 gain in angular resolution • x 10 gain in effective area  overall increase in sensitivity of ~ 9 • expect ~ 300 sources in -30 deg≤ l ≤ 30 deg. HESS map of the Gal.plane, total exp ~500 hours simulated CTA map, flat exposure ~ 5 hours/field Present and future DM searches with IACT

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