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

Jennifer Carson - GLAST2 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 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).

Jennifer Carson - GLAST3 GLAST Burst Monitor (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 NaI crystals (12) low-energy spectral coverage 8 keV to 1 MeV BGO crystals (2) high-energy spectral coverage 150 keV to 30 MeV Status: Being integrated onto spacecraft! PI: Dr. Charles Meegan (MSFC) GBM

Jennifer Carson - GLAST4 Large Area Telescope (LAT) Anti-coincidence detector: - Segmented - Vetos CR background Tracker (16 towers): - Facilitates pair conversion  Tungsten conversion foils - Measures e - /e + track  18 layers of Si strips  87 m 2 of Si! Calorimeter: - Measures photon energy  1536 CsI crystals ~20 MeV < E < ~300 GeV2.4 sr FoV

Jennifer Carson - GLAST5 LAT Features & Status Status: - All vibration tests completed - Currently in thermal vacuum testing - Detector response tests underway at CERN - Ships for integration onto spacecraft: 9/15/06 3  cm -2 s -1 in 1 yr ~10,000 sources! Src loc.: ~0.4’ – 10’ < 0.1° at E = 10 GeV < 0.35° at E = 1 GeV Angular Resolution (per  ) Point-source sensitivity Effective Area 10 4 cm 2 at 10 GeV 1 year 5 years thin thick all layers

Jennifer Carson - GLAST6 In 1 day, detect (at 5  ) the weakest EGRET sources. In 2 weeks, detect # of photons that EGRET detected in entire mission. Source Sensitivity: All-sky Scan Mode EGRET Fluxes - GRB (100sec) - PKS flare - 3C279 flare - Vela Pulsar - Crab Pulsar - 3EG (SNR g Cygni?) - 3EG C279 lowest 5s detection - 3EG (AGN) - Mrk Weakest 5  EGRET source 100 seconds 90 minutes (1 orbit) 1 day

Jennifer Carson - GLAST7 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 - GLAST8 Monitoring Variability with GLAST DC2 input model Likelihood output  Input models: - broken PL - Flux /  correlation - quiescence + moderate flare  Likelihood model: - single PL - daily averages during low/moderate flux levels Threshold for 1 st year public data release (~2/month)

Jennifer Carson - GLAST9 Monitoring Variability with GLAST DC2 input model Likelihood output Daily hardness ratios

Jennifer Carson - GLAST10 Monitoring Variability with GLAST DC2 input model Likelihood output Twelve-hour exposures

Jennifer Carson - GLAST11 Monitoring Variability with GLAST DC2 input model Likelihood output Six-hour exposures

Jennifer Carson - GLAST12 Courtesy of J. Chiang LATX-ray Snapshot SEDs with GLAST Hardness ratios SED evolution w/ synch. cooling  Light curves on few-hour timescales  R b /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 Twelve-hour exposures

Jennifer Carson - GLAST13 Time-averaged SEDs: Past Efforts Petry et al  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 R B  e - distribution (n e, p,  1,  2 )  Data cannot constrain B and  1  Need complete, simultaneous HE coverage! Low state High state Mrk 501

Jennifer Carson - GLAST14 Time-averaged SEDs with GLAST VERITAS sensitivity Simulated data Unbinned analysis LAT Mrk 501

Jennifer Carson - GLAST15 Time-averaged SEDs with GLAST VERITAS Unbinned analysis BeppoSAX LAT 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: R b, B, n e, p,  1,  2 Mrk 501

Jennifer Carson - GLAST16 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 - GLAST17 Backup Slides

Jennifer Carson - GLAST18 Survey Mode: LAT Sensitivity & Exposure Point source sensitivity in survey mode Exposure comparison: Survey vs. pointed (position of Mrk 421) 100 seconds 90 minutes (1 orbit) 1 day Courtesy of J. McEnery Point source detection limit Survey mode Pointed mode Exposure Pointed Survey Time (days)Time (minutes)