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G amma-ray L arge A rea S pace T elescope: Physics Goals and Instrument Status

Learn about the GLAST mission goals, instrument overview, international collaborations, scientific capabilities, and current status. Explore the physics objectives and key features of the Gamma-ray Large Area Space Telescope.

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G amma-ray L arge A rea S pace T elescope: Physics Goals and Instrument Status

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  1. Gamma-ray Large Area Space Telescope: Physics Goals and Instrument Status LAT Jennifer Carson SLAC/KIPAC for the GLAST LAT collaboration GBM GLAST lifetime: 5+5 years Launch date: Fall 2007

  2. GLAST LAT Collaboration Principal Investigator: Peter Michelson (Stanford & SLAC) ~225 Members (~80 Affiliated Scientists, 23 Postdocs, and 32 Graduate Students) Cooperation between NASA and DOE, with key international contributions from France, Italy, Japan and Sweden. Managed at Stanford Linear Accelerator Center (SLAC). • 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 Jennifer Carson - GLAST

  3. GLAST Burst Monitor (GBM) PI: Dr. Charles Meegan (MSFC) NaI crystals (12) low-energy spectral coverage 8 keV to 1 MeV BGO crystals (2) high-energy spectral coverage 150 keV to 30 MeV GBM http://f64.nsstc.nasa.gov/gbm/ 8 keV < E < 30 MeV (overlaps w/ LAT) FoV = 9.5 sr 12% energy resolution at 511 keV On-board localization: < 15° in 1.8s 2-3° localization in ~10s – minutes ~200 GRBs/year, > 50 in LAT FoV Status: Being integrated onto spacecraft! Jennifer Carson - GLAST

  4. Large Area Telescope (LAT) ~20 MeV < E < ~300 GeV 2.4 sr FoV • Tracker (16 towers): • Facilitates pair conversion •  Tungsten conversion foils • Measures e-/e+ track •  18 layers of Si strips •  87 m2 of Si! Anti-coincidence detector: - Segmented - Vetos CR background Calorimeter: - Measures photon energy  1536 CsI crystals Jennifer Carson - GLAST

  5. Angular Resolution (per ) < 0.1° at E = 10 GeV < 0.35° at E = 1 GeV Effective Area 104 cm2 at 10 GeV LAT Features & Status Point-source sensitivity thick 1 year thin 5 years 3  10-9 cm-2 s-1 in 1 yr ~10,000 sources! Src loc.: ~0.4’ – 10’ http://www-glast.slac.stanford.edu/software/IS/glast_lat_performance.htm • Status: • - All vibration tests completed • Currently in thermal vacuum testing • - Detector response tests underway at CERN • - Ships for integration onto spacecraft: 9/15/06 all layers Jennifer Carson - GLAST

  6. Source Sensitivity: All-sky Scan Mode 100 seconds EGRET Fluxes • - GRB940217 (100sec) • - PKS 1622-287 flare • - 3C279 flare • - Vela Pulsar • - Crab Pulsar • - 3EG 2020+40 (SNR g Cygni?) • - 3EG 1835+59 • - 3C279 lowest 5s detection • - 3EG 1911-2000 (AGN) • - Mrk 421 • - Weakest 5 EGRET source 90 minutes (1 orbit) In 1 day, detect (at 5) the weakest EGRET sources. In 2 weeks, detect # of photons that EGRET detected in entire mission. Jennifer Carson - GLAST 1 day

  7. 55 Days of GLAST Science Catalogs Diffuse Emission AGN Pulsars & SNRs UIDs Galaxies Dark Matter GRBs Solar System Sources Realistic! Uncertainty in instrument response & background, + realistic science models Jennifer Carson - GLAST

  8. DC2 input model Likelihood output Monitoring Variability with GLAST • Input models: - broken PL - Flux / correlation - quiescence + moderate flare • Likelihood model: - single PL - daily averages during low/moderate flux levels Threshold for 1st year public data release (~2/month) Jennifer Carson - GLAST

  9. DC2 input model Likelihood output Monitoring Variability with GLAST Daily hardness ratios Jennifer Carson - GLAST

  10. DC2 input model Likelihood output Monitoring Variability with GLAST Twelve-hour exposures Jennifer Carson - GLAST

  11. DC2 input model Likelihood output Monitoring Variability with GLAST Six-hour exposures Jennifer Carson - GLAST

  12. Courtesy of J. Chiang X-ray LAT Snapshot SEDs with GLAST SED evolution w/ synch. cooling  Light curves on few-hour timescales  Rb/D  If cool ~ days (c.f. Böttcher & Chiang 2002)… - 12-hour exposures: F/F < 10%, / < 5%   track particle cooling after flares  measure  as e-s cool constrain B, 1, 2, p 12-hr exp  snapshot SEDs during cooling Expect dozens of srcs w/ these measurements Hardness ratios Twelve-hour exposures Jennifer Carson - GLAST

  13. Time-averaged SEDs: Past Efforts Petry et al. 2000 • Simultaneous Mrk 501 data (1997) - RXTE, BATSE, HEGRA - Two epochs (1 week each) • Non-simultaneous EGRET data • One-zone, time-ave. SSC model: magnetic field B  blob radius RB  e-distribution (ne, p, 1, 2) • Data cannot constrain B and 1 • Need complete, simultaneous HE coverage! Mrk 501 Low state High state Jennifer Carson - GLAST

  14. Time-averaged SEDs with GLAST Unbinned analysis Simulated data LAT VERITAS sensitivity Mrk 501 Jennifer Carson - GLAST

  15. Time-averaged SEDs with GLAST With joint LAT/TeV observations, cover the entire HE peak…  Constrain 1 & B Plus X-ray observations…  Probe relative contributions of Synch. & IC cooling  Measure all parameters: Rb, B, ne, p, 1, 2 Unbinned analysis BeppoSAX LAT VERITAS Mrk 501 Jennifer Carson - GLAST

  16. Summary • The instruments - GBM is undergoing integration with the spacecraft - LAT is completing thermal vacuum tests, spacecraft integration begins soon • The strategy - Survey mode  entire sky every three hours - Thousands of new sources expected! • Examples of the (AGN) science - Track variability on hourly timescales during bright states - Snapshot SEDs of bright flares - Daily averages during moderate and low states - Time-averaged SEDs during quiescence  Test emission models, measure physical parameters First GLAST Science Symposium: February 2007 at Stanford! Jennifer Carson - GLAST

  17. Backup Slides Jennifer Carson - GLAST

  18. Survey Mode: LAT Sensitivity & Exposure Point source sensitivity in survey mode Point source detection limit 100 seconds 90 minutes (1 orbit) 1 day Courtesy of J. McEnery Exposure comparison: Survey vs. pointed (position of Mrk 421) Exposure Pointed Survey Time (minutes) Time (minutes) Time (days) Pointed mode Survey mode Jennifer Carson - GLAST

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