SLAC DoE Review June 14-16, 2005 GLAST Large Area Telescope Overview Elliott Bloom SLAC - KIPAC Stanford University

GLAST Large Area Telescope: Introduction Gamma-ray Large Area Space Telescope

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. 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  25 MeV Launch: August year mission (10-year goal) Large Area Telescope (LAT) spacecraft partner: GLAST Burst Monitor (GBM)

Generic Pair Conversion Telescope Calorimeter Calorimeter (energy measurement) (energy measurement) Conversion foils  e+e+ e-e- ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ Particle tracking detectors Charged particle anticoincidence shield Principle of Operation LAT

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. 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. 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

Large Area Telescope (LAT) e+e+ e–e–  Calorimeter Tracker ACD Grid Precision Si-strip Tracker (TKR) - Italy (ASI/INFN): provide Si-strip detectors & test all detectors, assemble & test detector trays, assemble & test TKR modules - Japan: provide Si-strip detectors & oversee detector production - SU-SLAC & UCSC (USA): provide Si-strip detectors, front-end electronics, cable plant Hodoscopic CsI Calorimeter (CAL) - IN2P3 (France): mechanical structure; CEA (France): engineering model prototypes of CDEs & test equipment; - Sweden: CsI xtals & acceptance testing; - NRL (USA): front-end electronics, provide photodiodes, assemble & test CDEs and CAL modules Segmented Anticoincidence Detector including micro-meteoroid shield / thermal blanket - GSFC (USA) Electronics System - SU-SLAC & NRL (USA): global electronics and DAQ equipment; flight software Mechanical Thermal System - SU-SLAC (USA): provide LAT Grid, thermal radiators, heat pipes & ancillaries LAT I&T - SU-SLAC (USA): assembly & test of LAT; provide particle/photon test beams - NRL (USA): instrument-level environmental tests

GLAST Large Area Telescope: GLAST Organization Gamma-ray Large Area Space Telescope

GLAST MISSION ELEMENTS GN HEASARC GSFC - - DELTA 7920H White Sands TDRSS SN S & Ku LAT Instrument Science Operations Center 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 Get final version from Rob.

GLAST is an International Mission LAT Collaboration (PI: P. Michelson - SU ) –NASA - DoE Cooperation on LAT GBM Collaboration (PI: C. Meegan - UofA, Huntsville ) –Small Context instrument Spacecraft and integration - Spectrum Astro Mission Management: NASA/GSFC Germany France Sweden Italy USA Japan

LAT Collaboration totalUS Collaboration members:16175 Members: 7743 Affiliated Sci.6728 Postdocs:174 SLAC:Members:15 Affiliated:2 Postdocs:2 United States California State University at Sonoma (SSU) University of California at Santa Cruz - Santa Cruz Institute of Particle Physics (UCSC/SCIPP) Goddard Space Flight Center – Laboratory for High Energy Astrophysics (NASA/GSFC/LHEA) Naval Research Laboratory (NRL) Ohio State University Stanford University – Hanson Experimental Physics Laboratory (SU-HEPL) Stanford University - Stanford Linear Accelerator Center (SU-SLAC) Texas A&M University – Kingsville (TAMUK) University of Washington (UW) Washington University, St. Louis (WUStL) France Centre National de la Recherche Scientifique / Institut National de Physique Nucléaire et de Physique des Particules (CNRS/IN2P3) Commissariat à l'Energie Atomique / Direction des Sciences de la Matière/ Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée (CEA/DSM/DAPNIA) Italy Agenzia Spaziale Italiana (ASI) Istituto di Astrofisica Spaziale (IASF, CNR) Istituto Nazionale di Fisica Nucleare (INFN) Japan GLAST Collaboration (JGC) Hiroshima University Institute for Space and Astronautical Science (ISAS) RIKEN Swedish GLAST Consortium (SGC) Royal Institute of Technology (KTH) Stockholm University

Current LAT Organization Chart for LAT Construction and Test Principal Investigator P. Michelson Instrument Scientist S. Ritz Senior Science Advisory Committee N. Gehrels Collaboration Science Team Project Manager L. Klaisner D. Horn, Deputy P. Drell, Deputy Instrument Science Performance S. Ritz, W. Atwood D. Horn Tracker R. Johnson ACD D. Thompson DAQ & FSW G. Haller Integration &Test E. Bloom SAS R. Dubois Mechanical M. Campell ISOC R. Cameron Calorimeter N. Johnson EPO L. Cominsky Chief of Electronics G. Haller System Engineering P. Hascall Mission Assurance J. Cullinan Production B. Esty Project Controls T. Boysen P. Drell* Administration D. Nicholson L. Klaisner ITAR Management S. Williams Staff Physicist T. Himel Design Int. & Anal. M. Nordby Deputy Principal Investigator Science Operations S. Ritz Deputy Principal Investigator Instrument/ Observ. Operations N. Johnson Staff Physicist C. Young Inst/Observatory Pre-launch Operations N. Johnson * Recently stepped down

LAT Organization Chart: Science Operations Phase Current Collaboration Science Groups 1a. Catalog - Seth Digel (SU-SLAC); Isabelle Grenier (CEA/ Saclay) 1b. Diffuse (Galactic and Extragalactic) and Molecular Clouds - Seth Digel (SU-SLAC); Isabelle Grenier (CEA/ Saclay) 2. Blazars and Other AGNs –Paolo Giommi (ASI), Benoit Lott (Bordeaux) 3. Pulsars, SNRs, and Plerions - Roger Romani (Stanford); David Thompson (GSFC) 4. Unidentified Sources, Population Studies, and Other Galaxies - Patrizia Caraveo (ASI ); Olaf Reimer (Stanford) 5. Dark Matter and Exotic Physics - Elliott Bloom (SU-SLAC); Aldo Morselli (INFN–Rome) 6. Gamma-Ray Bursts - Jay Norris (GSFC); Nicola Omodei (INFN-Pisa) 7. Solar System Sources - Gerry Share (NRL) 8. Calibration and Analysis Methods - William Atwood (UCSC); Steve Ritz (GSFC) 9. Multiwavelength Coordination Group – Roger Blandford (SU – KIPAC); David Thompson (GSFC)

GLAST Large Area Telescope: LAT Performance Gamma-ray Large Area Space Telescope

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 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 s) No expendables  long mission without degradation (5 year requirement, 10 year goal). GLAST LAT High Energy Capabilities

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 - ~5 arcmin localizations, depending on brightness.

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 - GRB (100sec) - PKS flare - 3C279 flare - Vela Pulsar - Crab Pulsar - 3EG (SNR  Cygni?) - 3EG C279 lowest 5  detection - 3EG (AGN) - Mrk 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

GLAST Large Area Telescope: LAT Science Gamma-ray Large Area Space Telescope

Connections: Quarks to the Cosmos The Universe as a Laboratory Beyond Einstein and the Big Bang What powered the big bang ? What is the mysterious dark matter that binds the universe ? What is the dark energy that drives the universe apart ? What is the nature of black holes and gravity beyond Einstein ? Are there hidden space-time dimensions ?

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? - Tune Kamae will explore the discovery space further in his talk tomorrow. Recommended by the National Academy of Sciences in their 2000 decadal study as the highest priority mid-sized mission * Connections related

GLAST is on the trail of Dark Matter SLAC User’s Community KIPAC Stanford University GLAST Team

Galaxy Clusters X-ray measurements Spiral Galaxies Rotation Curves Evolution of Universe  CDM Cosmology Big Bang CMB Baryonic matter Dark matter Total matter - There Are Signs of Dark Matter Everywhere -

Cosmology: Origin of Extragalactic Diffuse Radiation ► origin is a mystery; either sources there for GLAST to resolve (and study!) OR there is a truly diffuse flux from the early Universe Elasser & Mannheim, astro-ph/ EGRET constrains blazars to be > 25% of diffuse; annihilation of cosmological neutralinos has, in principle, a distinctive spectral signature Unique science for GLAST LAT baseline background limit Energy (keV) E 2 dJ/dE (keV/(cm2-s-keV-sr) EGRET steep- spectrum quasars Seyfert II galaxies Seyfert I galaxies Type 1a Supernovae discovery space blazars normal galaxies cluster mergers primordial diffuse new physics Also see: de Boer, Astro-ph/ (2004) “EGRET data show an intriguing hint of DM annihilation”. Appears as an excess of diffuse galactic  rays. M wimp ~ 50 – 100 GeV.

Halo Dark Matter Search with GLAST Wimp Annihilations in halo Clumps (b >|10| deg): – gamma continuum from pions very hard ~100 MeV (~ E 0 ) – lines (2 ,  ) Inverse Compton scattering (IC) from pions -> electrons (Baltz & Wai 04) – >GeV IC from e + starlight – near galactic plane < 30 deg (trapping by B field) Halo substructure models (figure) (J. Taylor & Babul 03 and Baltz preliminary) – subhalos away from plane – backgrounds much reduced KK DM Scenario – electron “line” (20% Br) smeared into a sharp edge via mainly IC – >500 GeV: ~ 100e ± /year edge height (Baltz & Hooper 05) – all-sky signature!

Discovery Potential: large extra dimensions “GLAST is a new dimension search engine” -- Savas Dimopoulos Theories with large (sub-millimeter) extra dimensions: - alternative way to solve the hierarchy problem of particle physics. - move the Planck scale to near the weak scale - observed weakness of gravity due to presence of n new spatial dimensions large compared to electroweak scale (Arkani-Hamed, Dimopoulos & Dvali 1998) Hannestad & Raffelt (2002, 2003) pointed out that Super Novae would produce Kaluza - Klein gravitons that are generic for these theories. - produced non - relativistically, so many are gravitationally bound to SN core (i.e., neutron star)  KK particle halo that shines in ~ 100 MeV  rays. - KK gravitons have gravitational strength decay (  ~ 10 9 years) to nn, e + e -, and  f KK is the fraction of SN energy emitted as KK gravitons. Authors calculate potential GLAST limit of F KK < for this source for n = 2, and < 0.5x10 -7 for n =3.

Discovery Potential: Large Extra Dimensions Constraints from EGRET observations (Hannestad & Raffelt 2003;Cassé, et al, Phys.Rev.Lett. 92 (2004) ):  Hannestad & Raffelt consider limits from viewing single neutron stars.  Cassé, et. al. focus on the sum over galactic bulge neutrons stars. Limits set by Cassé, et. al. using EGRET GB diffuse observations and estimates of the excess over that expected from the pure diffuse for 100 < E  < 300 MeV. The apparent excess is ascribed to KK  rays coming from the total of neutron stars in the galactic bulge, ~ 7x10 8. For n < 5 these are the best limits on the size of extra dimensions, and for n=1, 2, and 3 the effective Planck Scale is well beyond current collider technology. GLAST will do much better!

GLAST Large Area Telescope: Integration and Test Overview Gamma-ray Large Area Space Telescope

Particle Test Organization of I&T – Overview Integration Facilities Configuration and Test (IFCT) Mechanical Ground Support Equipment (MGSE) Integration, Test, and Calibration Electrical Ground Support Equipment (EGSE) / Online Software Science Verification Analysis and Calibration (SVAC) Management Particle Test

I&T Operations All operations in I&T are controlled by released procedures that outline each operation or test in detailed steps. Job Hazard Analysis and Mitigation (JHAM) forms are developed to identify potential hazards and highlight the mitigation plans for operations contained in the procedures. The JHAM is read, discussed and signed by operators prior to procedure execution as a review of potential hazards. Procedures for mechanical integration and electrical test are developed, and practiced with engineering models and mock-ups prior to use with flight hardware. A detailed LAT I&T daily schedule is updated and reviewed twice daily with the team to communicate planned activities and program priorities. A weekly meeting is held to provide a two week look ahead for subsystems to plan resources and identify shortages.

GLAST LAT Technical Status 14 CAL modules at SLAC. ACD being tested at GSFC. Delivery to SLAC in July. 7 SLAC. ~80m 2 of silicon detectors in hand. Two Towers in the GRID 04/11/05 Six Towers in the GRID by Tuesday 6/14/05

Almost Instant 4-Tower Gratification (SVAC)

A Two-Tower Gamma Ray Candidate

GLAST Large Area Telescope: Science Analysis Software (SAS) Gamma-ray Large Area Space Telescope

LAT Data Challenges Brings the collaboration together to work on science related activities, and encourages LAT collaborators to really focus on the science that the LAT will do. This provides a taste for what things might be like after launch. Drives a detailed study of the high level performance of the LAT. A detailed description of the instrument response over all energies and inclination angles is necessary for the high level analysis tools. “End-to-end” test of the simulation and analysis software all the way from low level detector simulations through to high level science analysis and source catalog generation. Design a progression of studies: –DC1. Modest goals. Contains most essential features of a data challenge. –DC2 in early More ambitious goals, incorporate lessons learned from DC1. ~One simulated month. –DC3 in Support for flight science production.

DC Components Focal point for many threads –Orbit, rocking, celestial coordinates, pointing history –Plausible model of the sky –Background rejection and event selection –Instrument Response Functions –Data formats for input to high level tools –First look at major science tools – Likelihood, Observation Simulator –Generation of datasets –Populate and exercise data servers at SSC & LAT –Code distribution on windows and Linux Involve new users from across the collaboration Teamwork! R.Dubois see

The Simulated DC1 Sky Extragalactic diffuse Galactic diffuse EGRET 3EG Fiddling 3C273/279 Our Sky R.Dubois

GLAST Large Area Telescope: Schedule and Conclusions Gamma-ray Large Area Space Telescope

The GLAST mission is completing the fabrication phase and is well into integration. LAT, GBM, and spacecraft assembly complete by January Delivery of the LAT and GBM instruments for observatory integration spring Observatory integration and test spring 2006 through summer CY07. Major scientific conference, the First GLAST Symposium, being planned for Launch in August 2007… Science Operations begin within 60 days … Join the fun! THE LOOK AHEAD Fabrication Instrument & S/C I&T Observatory I&T Launch

Extra Slides Follow

3 rd EGRET Catalog GLAST Survey: ~300 sources (2 days) GLAST Survey: ~10,000 sources (2 years) AGN - blazars unidentified pulsars LMC