1. Colliders To Cosmic Rays, Lake Tahoe February 25 – March 1, 2007 GLAST Large Area Telescope Overview Elliott Bloom SLAC - KIPAC Stanford University Representing the GLAST Collaboration

2. Why study  ’s? –  rays offer a direct view into Nature’s largest accelerators. – the Universe is mainly transparent to  rays with < 20 GeV that can probe cosmological volumes (z~700). Any opacity is energy-dependent for higher energy. – Most particle relics of the early universe produce  rays when they annihilate or decay. Two GLAST instruments: LAT: 20 MeV  300 GeV GBM: 10 keV  30 MeV Launch: Fall 2007 5-year mission (10-year goal) LEO @ 550km, ~26 o Large Area Telescope (LAT) spacecraft partner: GLAST Burst Monitor (GBM)

3. Overview of LAT Precision Si-strip Tracker (TKR)Precision Si-strip Tracker (TKR) ~80 m 2 Si, 18 XY tracking planes. Single- sided silicon strip detectors (228  m pitch) Measure the photon direction; gamma ID. Hodoscopic CsI Calorimeter(CAL)Hodoscopic CsI Calorimeter(CAL) Array of 1536 CsI(Tl) crystals in 8 layers. Measure the photon energy; image the shower. Segmented Anticoincidence Detector (ACD)Segmented Anticoincidence Detector (ACD) 89 plastic scintillator tiles and 8 ribbons. Reject background of charged cosmic rays; segmentation removes self-veto effects at high energy. Electronics SystemElectronics System Includes flexible, robust hardware trigger and software filters in flight software. Systems work together to identify and measure the flux of cosmic gamma rays with energy 20 MeV - >300 GeV. e+e+ e–e–  Calorimeter Tracker ACD Grid 16 towers-TKR+CAL+DAQ

4. GLAST MISSION ELEMENTS GN HEASARC GSFC - - DELTA 7920H White Sands TDRSS SN S & Ku LAT Instrument Science Operations Center (SLAC) GBM Instrument Operations Center GRB Coordinates Network Telemetry 1 kbps - S Alerts Data, Command Loads Schedules Archive Mission Operations Center (MOC) GLAST Science Support Center  sec GLAST Spacecraft Large Area Telescope & GBM GPS GLAST MISSION ELEMENTS

5. GLAST LAT Collaboration France –IN2P3, CEA/Saclay Italy –INFN, ASI Japan –Hiroshima University –ISAS, RIKEN Sweden –Royal Institute of Technology (KTH) –Stockholm University United States –California State University at Sonoma –University of California at Santa Cruz - Santa Cruz Institute of Particle Physics –Goddard Space Flight Center – Laboratory for High Energy Astrophysics –Naval Research Laboratory –Ohio State University –Stanford University (SLAC and HEPL/Physics) –University of Washington –Washington University, St. Louis Cooperation between NASA and DOE, with key international contributions from France, Italy, Japan and Sweden. Managed at Stanford Linear Accelerator Center (SLAC). Principal Investigator: Peter Michelson Peter Michelson (Stanford & SLAC) ~225 Members (includes ~80 Affiliated Scientists, 23 Postdocs, and 32 Graduate Students)

6. EGRET on CGRO firmly established the field of high-energy gamma-ray astrophysics and demonstrated the importance and potential of this energy band. GLAST is the next great step beyond EGRET, providing a leap in capabilities: Very large Field of View (FOV) (~20% of sky), factor 4 greater than EGRET Broadband (4 decades in energy, including the essentially unexplored region E > 10 GeV) Unprecedented Point Spread function (PSF) for gamma rays (factor > 3 better than EGRET for E>1 GeV). On axis >10 GeV, 68% containment < 0.12 degrees (7.2 arc-minutes) Large effective area (factor > 5 better than EGRET) Results in factor > 30 improvement in sensitivity below 100 at higher energies.Results in factor > 30 improvement in sensitivity below 100 at higher energies. Much smaller deadtime per event (27  sec, factor ~4,000 better than EGRET - 0.1 s) No expendables  long mission without degradation (5 year requirement, 10 year goal). GLAST LAT High Energy Capabilities

7. Cygnus region (15x15 deg) Dramatic Improvement in P oint S pread F unction and Source Localization over EGRET EGRET source position error circles are ~0.5°, resulting in counterpart confusion. GLAST will provide much more accurate positions, with ~30 arcsec to ~5 arcmin localizations, depending on brightness.

8. High energy source sensitivity: all-sky scan mode 100 sec * 1 orbit * ^ 1 day^ ^“rocking” all-sky scan: alternating orbits point above/below the orbit plane EGRET Fluxes - GRB940217 (100sec) - PKS 1622-287 flare - 3C279 flare - Vela Pulsar - Crab Pulsar - 3EG 2020+40 (SNR  Cygni?) - 3EG 1835+59 - 3C279 lowest 5  detection - 3EG 1911-2000 (AGN) - Mrk 421 - Weakest 5  EGRET source During the all-sky survey, GLAST will have sufficient sensitivity after O(1) day to detect (5  ) the weakest EGRET sources. *zenith-pointed

9. GLAST addresses a broad science menu of interest to both the High Energy Particle Physics and High Energy Astrophysics communities. Systems with super massive black holes & relativistic jets Gamma-ray bursts (GRBs) Pulsars Origin of Cosmic Rays Probing the era of galaxy formation Discovery! Particle Dark Matter? Other relics from the Big Bang? Extra dimensions? New source classes? Recommended by the National Academy of Sciences in their 2000 decadal study as the highest priority mid-sized mission

14. Gammas from lines  For  Line, energy = WIMP mass  For WIMP masses > M Z /2 can also have  Z 0 line  Measurement of line branching fractions would constrain particle theory   γ γ ? time   γ Z0Z0 ? Branching fractions are in the range 10 -2 - 10 -4

16. Where should we look for WIMPs with GLAST? Galactic center Galactic satellites Galactic halo Extra-galactic

19. The Galaxy Shinning in High Energy Gammas from the Annihilation of Dark Matter

20. http://glast.gsfc.nasa.gov/science/symposium/2007/program.html

23. GLAST LAT Mounted to Space Craft at General Dynamics in Gilbert, AZ. First communication with MOC on February 25, 2007.

24. Major scientific conference, the First GLAST Symposium, held February 1-4, 2007 at Stanford University. Observatory integration and test through late summer 2007. Launch in late fall 2007… Science Operations begin within 60 days THE LOOK AHEAD 2007 20062005 Fabrication Instrument & S/C I&T Observatory I&T Launch