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GLAST and Dark Matter

Gamma-ray Large Area Space Telescope. GLAST and Dark Matter. Jan Conrad Stockholm University Representing the GLAST-LAT Working group for Dark Matter and New Physics. Outline. The Gamma Ray Large Area Space Telescope (GLAST) Large Area Telescope (LAT)

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GLAST and Dark Matter

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  1. Gamma-ray Large Area Space Telescope GLAST and Dark Matter Jan Conrad Stockholm University Representing the GLAST-LAT Working group for Dark Matter and New Physics

  2. Outline • The Gamma Ray Large Area Space Telescope (GLAST) Large Area Telescope (LAT) • Complementary searches and predicted sensitivities • Galactic center, satellites, diffuse galactic, diffuse extragalactic, lines • Bonus track: e-(e+) detection Sensitivities are pretty much work in progress. We are currently updating with newest information on detector response and backgrounds.

  3. GLAST Key Features Large Area Telescope (LAT) • Large field of view • Large energy range • sub-arcmin source localization • Energy resolution @ 10 GeV < 6 %. Two GLAST instruments: LAT (Large Area Telescope): 20 MeV – >300 GeV GBM (GLAST Burst Monitor) 10 keV – 25 MeV Launch: February, 2008). 5-year mission (10-year goal) the Swedish astronaut GBM

  4. Detection technique Tracker (detection planes + high Z foils): photon conversion and reconstruction of the electron/positron tracks. Calorimeter: energy measurement. Anti-coincidenceshield (ACD): background rejection Signature of a gamma event: No ACD signal 2 tracks (1 Vertex)* Anticoincidence shield Conversion foils Particle tracking detectors e+ e– Calorimeter

  5. Overview of Large Area Telescope Precision Si-strip Tracker 18 XY tracking planes. Single-sided silicon strip detectors (228 mm pitch) Measure the photon direction; gamma ID. EGRET: spark chamber, large dead time, Hodoscopic CsI Calorimeter Array of 1536 CsI(Tl) crystals in 8 layers. Measure the photon energy; image the shower. EGRET: monolithic calorimeter: no imaging and decreased resolution Segmented Anticoincidence Detector 89 plastic scintillator tiles. Reject background of charged cosmic rays; segmentation reduces self-veto effects at high energy. EGRET: monolithic ACD: self-veto due to backsplash  e– e+ Tracker ACD [surrounds 4x4 array of TKR towers] Calorimeter • Field of View factor 4 • Point Spread function factor > 3 • effective area ( factor > 5 • Results in factor > 30 improvement in sensitivity below < 10 GeV, and >100 at higher energies. • Much smaller dead time factor ~4,000 • No expendables

  6. The GLAST-Large Area Telescope Team • France • IN2P3, CEA/Saclay • Italy • Universities and INFN of Bari, Perugia, Pisa, Roma Tor Vergata, Trieste, ASI, INAF • Japan • Hiroshima University, ISAS, RIKEN • United States • CSU Sonoma. UC Santa Cruz, Goddard, NRL, OSU, Stanford (SLAC and HEPL), Washington, St. Louis • Sweden • Royal Institute of Technology (KTH), Stockholm University, Kalmar University Principal Investigator: Peter Michelson (Stanford & SLAC) ~270 Members (includes ~90 Affiliated Scientists,37 Postdocs, and 48 Graduate Students)

  7. GEANT4 detector simulation Simulation: Detailed geometry over 45,000 volumes, and growing! Interaction Physics: QED: derived from GEANT3 with extensionsto higher and lower energies (alternatemodels available) Hadronic: based on GEISHA (alternatemodels available) and currently tested on beam test data Propagation Full treatment of multiple scattering Surface-to-surface ray tracing. δ electrons Digitization: Includes information from actual LAT tests detailed instrument response dead channels noise etc. Deadtime Effects High-energy g interacts in LAT Black: Charged particles White: Photons Red: Deposited energy Blue: Reconstructed tracks Yellow: Inferred γ direction F. Longo

  8. Some photon candidates (in the calibration unit)

  9. 0.01 GeV 0.1 GeV 1 GeV 10 GeV 100 GeV 1 TeV Active Galactic Nuclei Solar flares Unidentified sources Cosmic ray acceleration Pulsars Gamma Ray Bursts GammaRay Large Area Space Telescope science menu Quantum Gravity ? Strange Quark Matter ? Dark matter (neutralinos, axions etc, etc…)

  10. Background to all photons: charged particles - Advanced MV method - Final rejection power: 1/106 -γ efficiency: 0.8 Black, total; light green, GCR protons; lavender, GCR He; red, GCR electrons; blue, albedo protons; light blue, albedo positrons; green, albedo electrons; and yellow albedo gammas. Sreekumar et al. Astrophys.J.494:523-534,1998 • Strong et al.Astrophys.J.613:956-961,2004 T. A. Porter et al. 30th ICRC, Merida, Mexico

  11. Photon background: galactic diffuse - conventional and optimized GALPROP model ’conventional’ GALPROP: calibrated with locally measured electron and proton,helium spectra, as well as synchroton emission ’optimized’ GALPROP: see next slide http://galprop.stanford.edu/web_galprop/galprop_home.html Optimized Conventional Regarding EGRET GeV excess: Stecker, Hunter, Kniffen e-Print: arXiv:0705.4311 [astro-ph] EGRET excess instrumental, i.e. disappears with correct calibration Porter, Atwood, Baughman, Johnson ICRC 2007 e-Print: arXiv:0706.0220 [astro-ph] EGRET excess becomes larger if cp bg taken into account Strong, Moskalenko, Reimer, ApJ537, 736, 2000 Strong, Moskalenko, Reimer, ApJ613, 962-976, 2004

  12. ”Optimized model”: allow average CR spectrum to deviate from local spectrum Use antiprotons to constrain average proton spectrum Electrons adjusted to recover EGRET galactic diffuse con’t slide from Igor Moskalenko

  13. GLAST complementary searches See talk by Pieri

  14. Generic WIMP flux • γ yield per annihilation • Flux from given source ISASUGRA line continuum Annihilation cross setcion. Constraint by cosmology to ~ 10-26 cm2 Dark Matter structure

  15. Galactic center (strategy) Assume a NFW profile Simulate WIMP signal Simulate background (optimized/conventional galprop) Simulate GLAST response (ObsSim) Choose ROI (0.5 degrees, E > 1 GeV) Check if WIMP + background can be distinguished from background only (using χ2for simplicity).

  16. GC: sensitivity ”Excluded” by EGRET1) • Mayer-Hasselwander et. al. • Astron.Astrophys.335:161-172,1998 E. Nuss, A. Lionetto, A. Morselli

  17. Senstivity to lines: procedure • Look for line signal in annulus • Assume background given by conventional/optimized model • Simulate response to monoenergetic line (ObsSim) • 5 years of operation • Check if line+background can be distinguished from background only using: • Vary s until ”averaged (bootstrapped) Δχ > 25 ( 5 σ) No assumptions on where this line comes from

  18. Line 5σ sensitivity (5 year observation) Simulated detector response to δ function in energy Conventional background 10-8 10-9 Y. Edmonds, E. Bloom, J. Cohen-Tanugi

  19. Semi-analytic models of halo substructure1) Signal, background flux (ObsSim) inside the tidal radius as measure of significance WIMP mass = 100GeV Satellites/Subhalos P. Wang, L. Wai, E. Bloom How many sources at which significance ? 100 GeV WIMP, 10 σ detection No. of satellites GLAST 5-yrs <σannihv >[2.3e.-26 cm-3s-1] GLAST 1-yr WIMP mass [GeV] Signficance [ σ] Green: optimized Red: conventional • Taylor & Babul, MNRAS, 364, 535 (2004) - MNRAS, 364, 515 (2005) -MNRAS, 348, 811 (2004)

  20. Subhaloes vs. other sources Jan Conrad (KTH, Sthlm) La Thuile March 200720 Taylor et al. 1st GLAST symposium

  21. Cosmological WIMP annihilation Halo structures (NFW etc. subhaloes) and halo mass function Particle Physics (annihilation x-section) Particle Physics (continuum plus line yield) Cosmology Absorption Ullio, Bergström, Edsjö, Lacey Phys Rev. D. 66 123502 (2002)

  22. Cosmological WIMPS: Sensitivity Includes charged particle background Band corresponds to: [EGRET] Sreekumar et al. Astrophys.J.494:523-534,1998 [EGRET reanalyzed] Strong et al. Astrophys.J.613:956-961,2004 ”Blazar” model Ullio et al. Simple and idealized χ2 analysis GC, 5 years Phys Rev. D. 66 123502 (2002) A. Sellerholm, J.C., L. Bergström, J. Edsjö

  23. Galactic Halo Full detector response simulation to galactic diffuse signal (plus WIMP) Likelihood fit to both the energy and spatial distribution Sensitivity via pseudoexperiments of 1 year GLAST operation EG, 1 year A. Sander, R. Hughes, P. Smith, B. Winer

  24. LAT e+/e- detection: capabilities Effective e+/e- detection with small hadron contamination (few percent) Cuts based on event topology Energy resolution between 5 and 20 % A. Moiseev

  25. LKP1) mass = 300 GeV and 600 GeV Single (close) clump (in principle, consider overlap of many clumps in diffusion equation) 1) Baltz & Hooper, JCAP 7 (2007) Illustrative example Reconstructed LAT electron spectrum A. Moiseev

  26. A teaser ..... Inert Doublet model: ”Higgs Dark Matter” extra scalar doublet, introducing three new fields (1 charged, 2 scalar) Line flux large relative to continuum flux Uses ObsSim with Blazar background Line sensitivity in EG background e.g.: Barbieri et al., Phys. Rev. D 74 (2006) 0015007 Gustafsson, Lindström, Bergström,Edsjö, astro-ph/0703512 (accepted by PRL) 5 σ NFW 5 σ NFW plus sh A. Sellerholm, J.C.

  27. Standard Conclusions • The GLAST LAT team pursuis complementary searches for signatures of particle dark matter. • GLAST will shed light on the multi-GeV EGRET data. • GLAST has the potential to either discover or to constrain particle dark matter and establish contact between LHC discovery and Dark Matter • GLAST will be able to image Dark Matter Halo structure The Galactic center shining in DM gamma rays Jan Conrad (KTH, Sthlm) La Thuile March 200727

  28. More (interesting ?) conclusions ... The place to look for GLAST performance for your calculations is: Paper summarizing sensitivities in (σv,m) space for all what has been presented today to be submitted later this year. The official GLAST-Launch date is: Feb 5, 2007 GLAST data will be public after one year GLAST is not only a photon detector ! GLAST is not only more sensitive than EGRET, but will also be better prepared (in terms of systematics and ”instrumental” background (however, it is not flying yet !) There are different ways to collaborate with us, if you have ideas do not hesitate to talk to me during ENTAPP or or go via any other GLAST member. www-glast.slac.stanford.edu/software/IS/glast_lat_performance.htm

  29. Acknowledgements The Dark Matter and New Physics WG of GLAST-LAT - in particular: Ted Baltz (Google), E. Bloom, Y. Edmonds, P. Wang, L. Wai (Yahoo), J. Cohen-Tanugi(SLAC/KIPAC) I. Moskalenko (Stanford) A. Morselli, A. Lionetto (INFN Roma/Tor Vergata) E. Nuss (Montpellier) R. Hughes, A. Sander, B. Winer (Ohio State) L. Bergström, J. Edsjö, A. Sellerholm (Stockholm) A. Moiseev (Goddard) Not covered: - point sources of DM (Bertone, Rando, Morselli). - mSUGRA exclusion (Lionetto)

  30. BACKUP SLIDES

  31. Identification of Dark Matter subhalos 5 yr GLAST, single clump, 1 degree rejected Molecular cloud rejected 200 GeV WIMP 30 GeV WIMP rejected allowed Pulsar Baltz, Taylor, Wai, astro-ph/0610731 Jan Conrad (KTH, Sthlm) La Thuile March 200731

  32. mSUGRA exclusion (Galactic Center) A0 = 0 Similar ”analysis” as in generic WIMP case 5yr, 3σ discovery trunc. NFW Acc. Limits: Baer et al. hep-ph/0405210 A.Morselli, E. Nuss, A. Lionetto. First Glast Symposium, 2007 Jan Conrad (KTH, Sthlm) Scineghe07 June 200732

  33. tang  = 60 A0 = 0

  34. Sagittarius

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