GLAST

1
GLAST High Energy Astrophysics in the GeV
region F.Longo1 N.Omodei2 University of
Trieste and INFN Trieste INFN Pisa For the LAT
collaboration More details at
http//glast.gsfc.nasa.gov
http//www-glast.stanford.edu
2
Outline

• High Energy Gamma-ray sky science objectives
• GLAST Mission
• Instrument Description
• SW data analysis
• Data Challenges
• GRB with GLAST

3
GLAST Key-Features

• Two GLAST instruments
• LAT 20 MeV - gt300 GeV
• GBM 10 keV - 25 MeV
• Launch Early 2008.
• 565 km, circular orbit
• 5-year mission (10-year goal)
• International Collaboration
• Huge field of view
• LAT 20 of the sky at any instant in sky survey
  mode, expose all parts of sky for 30 minutes
  every 3 hours.
• GBM whole unocculted sky at any time.
• Huge energy range, including largely unexplored
  band 10 GeV- 100 GeV
• New generation space telescope, high-energy
  astrophysics, part of the Exploration of the
  Universe division (NASA).

4
Basics of a pair conversion telescopes

• Intent is to Measure the direction, the energy,
  and the arrival time of celestial gamma-rays

• Tracker/Converter (direction)
• detection planes high Z foils photon
  conversion and reconstruction of the
  electron/positron tracks.
• Multiple scattering vs Efficiency
• Calorimeter (energy measurement).
• Thickness (and mass) vs energy resolution
• Anti-coincidence shield (ACD) background
  rejection
• cosmic rays flux 104 higher than the gamma
  flux).
• Monolithic vs Segmented
• Signature of a gamma event
• Three-in-a-raw trigger
• No ACD signal
• 2 tracks (1 Vertex)
• Calorimeter signal (Energy)
• Low E? limit
• from pair-production threshold and PSF
  limitations from multiple scattering
• High E? limit
• from limitations on Aeff (1m2) and sharp drop
  in sources flux, e.g. (Fcrab_E?gt300GeV)x(1year)x(1
  m2)25?

?
Anticoincidence Shield
Conversion Foils
Particle tracking detectors
e
e
Calorimeter
DAQ
5
Physics Program

• GLAST will be the reference gamma-ray observatory
  
• 5 years life requirement 10 years goal
• Will provide high energy gamma-ray data (public)
  for the first time with unprecedented
  resolution/statistics
• Vast, interdisciplinary physics program and
  scientific community (astro-particle and
  traditional astrophysics)
• Multi-wavelength campaigns (AGNs)
• Networked to other space/ground facilities for
  alert (bursts and transients)

6
GLAST Science

• GLAST will have a very broad menu that includes
• Systems with supermassive black holes (Active
  Galactic Nuclei)
• Gamma-ray bursts (GRBs)
• Pulsars
• Solar physics
• Origin of Cosmic Rays
• Probing the era of galaxy formation, optical-UV
  background light
• Solving the mystery of the high-energy
  unidentified EGRET sources
• Discovery! Particle Dark Matter? Other relics
  from the Big Bang? Extra dimensions? Testing
  Lorentz invariance. New source classes.
• Huge increment in
  capabilities.

GLAST draws the interest of both the the High
Energy Particle Physics and High Energy
Astrophysics communities.
7
Technology impact angular resolution
EGRET (1991-2000) Phases 1-5

• Spark chamber
• sense electrode spacing mm
• sensitive layer depth cm
• up to 28 hit over gt1m

LAT (2007- gt2012) 1-yr simulation

• Si-strip detectors
• sense electrode spacing 0.2mm
• better single hit resolution
• sensitive layer depth 0.4mm
• up to 36 hit over 0.8m
• converter proximity to minimize MCS

Cygnus region (150 x 150), Eg gt 1 GeV
8
GLAST LAT High Energy Capabilities

• EGRET on GRO 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 huge leap in capabilities
• Very large FOV (20 of sky), factor 4 greater
  than EGRET
• Broadband (4 decades in energy, including
  unexplored region E gt 10 GeV)
• Unprecedented PSF for gamma rays (factor gt 3
  better than EGRET for Egt1 GeV)
• Large effective area (factor gt 5 better than
  EGRET)
• Results in factor gt30-100 improvement in
  sensitivity
• Much smaller deadtime per event (25 microsec,
  factor gt4,000 better than EGRET)
• No expendables long mission without
  degradation

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Resolving the background

• With a best PSF arcmin new can
• complete EGRET catalog (unidentified sources)
• build a LAT catalog
• resolve diffuse into sources
• identify new classes of sources and possibly DM
  sources (NO radio partner)

AO PSF vs Energy Improvements expected and under
evaluation due to converter reduction
10
Technology impact sensitivity

• HEP detectors and electronics for
• low aspect ratio for enhanced FOV
• low noise detectors for self-trigger capability
  and high data rate - L0T 10KHz
• highly efficient ACD and on-board computing
  power for background reduction - up to 104
• fast detectors and electronics for reduced dead
  time - 26ms

Integral Flux (Egt100 MeV) cm-2s-1
EGRET - 5 years map
GLAST 1 year sky-survey simulation
Populate large catalog of sources to subtract
from residual background ? particularly relevant
for extra-galactic DM search
11
EGRET ? GLAST
LAT 1st Catalog gt9000 sources possible
EGRET 3rd Catalog 271 sources
12
GLAST MISSION ELEMENTS
GLAST MISSION ELEMENTS
Large Area Telescope GBM
m

sec
GPS

-

Telemetry 1 kbps
GLAST Spacecraft

TDRSS SN S Ku
DELTA 7920H


S
-
-

GN

LAT Instrument Science Operations Center
White Sands
Schedules
HEASARC GSFC
Mission Operations Center (MOC)
GLAST Science Support Center
Schedules
GBM Instrument Operations Center
GRB Coordinates Network
Alerts
Data, Command Loads
13
GBM Detectors
Provides spectra for GRB from 10 keV to 30
MeV. Provides wide sky coverage (8 sr), enables
autonomous repoints to allow for high energy
afterglow observations with the LAT.
14
GBM Collaboration
National Space Science Technology Center
University of Alabama in Huntsville
NASA Marshall Space Flight Center
Max-Planck-Institut für extraterrestrische Physik
Giselher Lichti (Co-PI) Andreas von
Keinlin Volker Schönfelder Roland Diehl Jochen
Greiner Helmut Steinle
Michael Briggs William Paciesas Robert
Preece Narayana Bhat Marc Kippen (LANL)
Charles Meegan (PI) Gerald Fishman Chryssa
Kouveliotou Robert Wilson
On-board processing, flight software, systems
engineering, analysis software, and management
Detectors, power supplies, calibration, and
analysis software
15
Key GBM Science Performance Requirements Summary
16
The GLAST Large Area Telescope

• Precision Si-strip Tracker (TKR)
  18 XY tracking planes. 228 ?m pitch). High
  efficiency. Good position resolution (ang.
  resolution at high energy) 12 x 0.03 X0 front
  end gt reduce multiple scattering. 4 x 0.18
  X0 back-end gt increase sensitivity gt1GeV
• CsI Calorimeter(CAL)
• Array of 1536 CsI(Tl) crystals in 8 layers.
  Hodoscopic gt Cosmic ray rejection.
• gt shower leakage
  correction.
• 8.5 X0 gt Shower max contained lt100 GeV
• Anticoincidence Detector (ACD)
• Segmented (89 plastic scintillator tiles)
  
• gt minimize self veto,
• Reject background of charged cosmic rays
• Electronics System Includes flexible, robust
  hardware trigger and software filters.

Height/Width 0.4 gt Large field of view
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From EGRET to GLAST
GLAST 2008 on ..
30Mev-30GeV Peak Aeff 1500cm2 (on-axis)
EGRET 1991-2000
20Mev-300GeV Peak Aeff 10000cm2
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The LAT instrument how we built it

• Overall modular design
• 4x4 array of identical towers - each one
  including a Tracker, a Calorimeter and an
  Electronics Module.
• Surrounded by an Anti-Coincidence shield (not
  shown in the picture).

• Tracker/Converter (TKR)
• Silicon strip detectors (single sided, each
  layer is rotated by 90 degrees with respect to
  the previous one)
• W conversion foils
• 80 m2 of silicon
• 106 electronics chans
• fully digital electronics
• High precision tracking, small dead time

• Anti-Coincidence (ACD)
• Segmented (89 tiles)
• Self-veto _at_ high energy limited
• 0.9997 detection efficiency (overall)

• Calorimeter (CAL)
• 1536 CsI crystals
• Analog 4 range readout
• 8.5 X0
• Hodoscopic
• Shower profile reconstruction (leakage
  correction)

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Italian responsibilities for the LAT-TKR
construction
delivery of the GLAST TKR detector,16 towers,
assembled and tested, by 09/2005
SSD procurement and test (INFN/ASI)
Ladder assembly (GA/Mipot) and test (INFN/ASI)
Trays panels production (Plyform)
Trays panels structural test (ESPI/static)
(INFN-Pisa)
Trays panels thermal-vacumm test (INFN/ASI)
Trays panels integration with ladders and
electronics (GA)
Trays functional test (INFN/ASI)
Trays C.R. burn-in test (INFN/ASI)
Tower assembly (INFN/ASI)
Tower functional test (INFN/ASI)
Tower environmental test (Alenia/INFN/ASI)
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cucina italiana I tower ingredients
38 C-fiber facesheets

• 576 SSD
• 55K channels
• 228 mm pitch

19 Al honeycomb
38 C-C MCM closeouts
38 C-C structural closeouts
36 Multi-Chip Modules
4 C-fiber sidewalls
8 kapton flex cables
36 kapton bias circuits
1000 screws (several types)
192 3 X0 W tiles 64 12 X0 W tiles
glue, paint, tape
21
Tracker construction workflow
Module Structure Components SLAC Ti parts,
thermal straps,fasteners. Italy (Plyform)
Sidewalls
18
Tracker Module Assembly and Environmental Test
Italy (INFN, Alenia Spazio)
342
Tray Assembly and Test Italy (INFN, GA)
inter-tower stay-clear 2mm
Electronics Fabrication, burn-in, Test UCSC,
SLAC (Teledyne)
inter-ladder // 100mm
648
Readout Cables UCSC, SLAC (Parlex, Pioneer)
22
May 17, 2005
May 19, 2005
April 8, 2005
October 3, 2005
September 20, 2005
June 6, 2005
October 19, 2005 TKR integration complete!
October 10, 2005
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LAT Milestones

• 12-2004 delivery of flight unit from subsystems
  start
• 12-2005 LAT integration completed
• TKR, CAL, ACD, ELX
• 9-2006 LAT environmental test cycle
• vib, EMI-EMC, TVAC
• no performance degradation
• 12-2006 GLAST observatory integration completed
• 6-2007 GLAST observatory environmental test
  cycle
• 10-2007 ship to launch site

All flight modules (Si TKR CsI CAL) integrated
in the flight grid
ACD being installed on the LAT
24
The LAT Tracker numbers
11500 sensors 360 trays 1M channels 83 m2 Si
surface gt 240K functional test recorded in DB
30M strip tested (30 test/strip avg)
gt 60 physicist and engineers involved in the
italian teams from INFN in partnership with ASI
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16 Towers with ACD
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Triggering and Onboard Data Flow
Hardware Trigger
On-board Processing
Onboard filters reduce data to fit within
downlink, provide samples for systematic studies.
Hardware trigger based on special signals from
each tower initiates readout Function did
anything happen? keep as
simple as possible

• flexible, loose cuts, hierarchical
• The FSW filter code is wrapped and embedded in
  the full detector simulation
• leak a fraction of otherwise-rejected events to
  the ground for diagnostics, along with events ID
  for calibration

signal/background can be tuned
? rate a few Hz
Combinations of trigger primitives
TKR - 3 xy in a row workhorse g trigger

• CAL
• LO 100MeV
• HI 1GeV
• ACD g-veto, HI trigger

Total Downlink Rate lt400 Hzgt
On-board science analysis transient detection
(bursts)
Upon a trigger, all subsystems are read out in
27ms
Spacecraft
Instrument Total Rate lt3 kHzgt
using ACD veto in hardware trigger
current best estimate, assumes compression, 1.2
Mbps allocation.
27
Simulation and Analysis
Simulation
Real LAT Data
gamma-ray sky model
background fluxes
Particle Generation and Tracking
Instrument Response(Digitization), Formatting
Trigger and OnboardFilter (wrapped FSW)
Event Reconstruction
Detector Calibration
High-level Science Analysis
Event Classification
Performance
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GLEAM
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Structure for celestial source simulators

• The development of a celestial source model for
  GLAST/LAT software implies
• Capability to use the models within the full
  Monte Carlo of the LAT instrument (GLEAM)
• Capability to use the models within
  observationSim, the science simulator.
• Source simulators
• the GRB physical model
• GRB phenomenological model
• High level Pulsars simulations (polar cap -
  outer gap model)
• Sources have been using by the GLAST community
  and are included in the next Data Challenges.

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Source and Background Flux

• Sky Simulation
• J.McEnery et al., GLAST symposium
• Galactic Diffuse
• AGN, GRB, DM
• Galactic populations (PSR, SNR, MuQSO)
• Extragalactic Diffuse
• Sun and Moon

• Background Flux
• J. Ormes et al., GLAST symposium
• Albedo ee- flux from AMS and Marya (but AGILE!)
• Primary cosmic proton flux
• New Albedo ? flux
• Waiting for PAMELA results

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.
31
Geometry Repository

• A complex instrument GLAST geometry is formed
  by more than 40000 different kind of volumes.
• A typical problem in HEP experiments (and GLAST
  is not so big)
• The geometry database in GLAST is in XML, a quite
  common choice (LHCb, Atlas and more) today
• detModel is a set of C classes to parse and
  represent in memory such XML description
• Used by various clients (reconstruction
  algorithms, MonteCarlo simulation, graphics etc.
  etc)

32
LAT GeometrySimulation and Reconstruction
33
Simulation Based on GEANT4
High-energy ? interacts in LAT
Geometry Detail Over 45,000 volumes, and
growing! Includes tracker electronics boards
mounting holes in ACD tiles
spacecraft details
and much more Interaction Physics QED
derived from GEANT3 with extensions to
higher and lower energies (alternate models
available) Hadronic based on GEISHA
(alternate models available) Propagation
Full treatment of multiple scattering
Medium-dependent range cut-off
Surface-to-surface ray tracing. Includes
information from actual LAT tests detailed
instrument response dead channels noise
etc. Overall Deadtime Effects
Black Charged particles White Photons Red
Deposited energy Blue Reconstructed
tracks Yellow Inferred ? direction
34
Tracker Simulation / Digitization
Geant4 treats the entire silicon plane as a unit.
Energy is deposited with landau fluctuations.
Using this information, the digitization
algorithm then determines which strips are hit.
(below threshold)
35
Event Reconstruction

• Sequence of operations, each implemented by one
  or more Algorithms, using TDS for communication
• Trigger analysis is there a valid trigger?
• Preliminary CAL to find seed for tracker
• Tracker recon pattern recognition and fitting to
  find tracks and then photons in the tracker
  (uses Kalman filter)
• Full CAL recon finds clusters to estimate
  energies and directions
• Must deal with significant energy leakage since
  only 8.5 X0 thick
• ACD recon associate tracks with hit tiles to
  allow rejection of events in which a tile fired
  in the vicinity of a track extrapolation
• Background rejection consistency of patterns
• Hits in tracker
• Shower in CAL alignment with track, consistency
  with EM shower

An easy rejection
36
The Illustrated Tracker Reconstruction
Tkr Clustering Associate adjacent hit strips to
form strip clusters (corrected for hot and dead
strips)
Pattern Recognition Associate strips to form
candidate tracks (Combinatoric pattern
recognition using Kalman Filter to accept/reject
candidate hits)
Track Fit Take candidate tracks and track energy
estimate and fit using a Kalman Filter
Vertexing Combine fit tracks to form common
vertex point- If one track, vertex is head of
track - If two tracks dont combine well, keep
as separate vertices
37
LAT reconstruction
Hit ACD tile
1-GeV g
Thin-converter hits
Gap dead material between tracker towers
Thick-converter hits
Blank-converter hits
Energy lost in tracker
Gap between CAL towers
Calorimeter crystals
Energy lost in CAL
Leakage out the back of the CAL
38
Backgrounds
Reentrant positrons
Primary protons
log10(E/MeV)
39
Remove Irreducible Background from CT Training
Sample
A large portion of the residual backgrounds are
unavoidable. These are photons produced in the
material outside the ACD. These pollute the
training sample with "signal" in the background
sample.
Residual Background
Direction Correlated Events
Blanket Conversion
Tile Conversion
Remove All e with McZDir lt -.2 from Training
Sample
40
First Irreducible Back Grounds
Uncorrelated
Correlated
e Blanket Conversion
Proton - Blanket Interaction
gt 60 Remaining background are from gs produced
locally They are Irreducible
41
Full sky simulation of GLAST Science
Catalogs Diffuse Emission AGN Pulsars
SNRs UIDs Galaxies Dark Matter GRBs Solar System
Sources
Realistic 55 days (precession period) of LAT
obs! Uncertainty in instrument response
background, realistic science models See APOD
May 31, 2006
42
Data Challenges
Data challenges provide excellent testbeds for
science analysis software. Full observation,
instrument, and data processing simulation. Team
uses data and tools to find the science. Truth
revealed at the end.

• A progression of data challenges.
• DC2 NOW (closeout 31 May - 02 June). 55
  simulated days all-sky survey.
• first catalog
• add source variability (AGN flares, pulsars).
  add GBM. benchmark data processing/volumes.
• closeout end of May (gt100 participants)
• DC1 in 2004. 1 simulated week all-sky survey
  simulation, very successful.
• find the sources, including GRBs
• a few physics surprises
• DC3 in 2007. Support for flight science
  production.

43
Purposes of the Data Challenges

• End-to-end testing of analysis software.
• Familiarize team with data content, formats,
  tools and realistic details of analysis issues
  (both instrumental and astrophysical).
• If needed, develop additional methods for
  analyzing LAT data, encouraging alternatives that
  fit within the existing framework.
• Provide feedback to the SAS group on what works
  and what is missing from the data formats and
  tools.
• Uncover systematic effects in reconstruction and
  analysis.

Support readiness by launch time to do all
first-year science.
44
The GLAST Observatory
Meegan Michelson Ritz Atwood
Blackwood Harnden Johnson
http//glast.gsfc.nasa.gov/public/resources/images
/
45
GLAST LAT Collaboration

• 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
• France
• IN2P3, CEA/Saclay
• Italy
• INFN, ASI, INAF
• Japanese GLAST Collaboration
• Hiroshima University
• ISAS, RIKEN
• Swedish GLAST Collaboration
• Royal Institute of Technology (KTH)
• Stockholm University

PI Peter Michelson (Stanford SLAC) 225
Members (including 80 Affiliated Scientists,
plus 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).

• Join Adventure between HEP and Astrophysics

46
GLAST LAT Science

• Science Working Groups
• Calibration and Analysis Methods (L.Latronico,
  P.Bruel)
• Blazars and other AGNs (G.Tosti, B.Lott)
• Diffuse and Molecular Clouds (T.Porter I.Grenier)
• Catalogs (S.Digel, I.Grenier)
• Pulsars, SNR and Plerions (R.Romani, A.Harding)
• GRB (N.Omodei, V.Connaughton)
• Sources in the Solar System (G.Share, F.Longo)
• Unidentified sources, populations and other
  galaxies (P.Caraveo, O.Reimer)
• Dark Matter and new physics (J.Conrad, R.Johnson)
• (just rotated A.Morselli, E.Bloom)
• Satellite groups
• IRF Working Group (R.Rando)
• IRF Monitoring (ISOC) (C.Cecchi)
• Beam Test Analysis (L.Latronico, P.Bruel)

47
Key LAT Science Performance Requirements Summary

• LAT meets all requirements, and many analysis
  improvements are underway.
• See http//www-glast.slac.stanford.edu/softwa
  re/IS/glast_lat_performance.htm

48
LAT Performance
http//www-glast.slac.stanford.edu/software/IS/gla
st_lat_performance.htm
Energy dispersion
relative Aeff vs g angle at 10GeV
68 containment of the PSF
update before pre-launch package
Energy dispersion vs g angle
on-axis effective area
PSF vs g angle at 10GeV
49
Gamma-Ray Bursts

• Serendipitously discovered in the 1969-70 by the
  Vela satellites
• Rapid flashes of high energy. Variable sources,
  non repetitive (destructive).
• Big statistics (gt2700 GRBs) collected by
  CGRO/BATSE detector (25 keV- 1 MeV)
• The discovery of the afterglow revealed the host
  galaxy extragalactic origin directed observed!
• Swift GRB 050904 z 6.29 0.01!!
• Their nature is still unclear, destructive
  phenomena, probably associated with the
  explosions of massive stars.

Isotropic distribution of GRB in the sky
(BATSE). This was the first proof of their
Extragalactic origin.
50
Gamma Ray Bursts

• GRBs phenomenology
• Dramatic variations in the light curve on a very
  short time scale
• Isotropic distribution in the sky (basically
  from BATSE, on board CGRO, but little data _at_
  energies gt 50 MeV)
• Non repeating (as far as we can tell)
• Spectacular energies ( 1051 1052 erg)

• GRBs physics
• GLAST should detect 50 GRBs/year above 100 MeV
  (a good fraction of them localized to better than
  10 in real time)
• 10 keV-300 GeV coverage from GBMLAT
  spectroscopy and timing studies to identify
  acceleration mechanism
• Quantum gravity effects from time dispersion of
  light curve vs Z
• large energy lever arm
• minimal dead time

Simulated GRB spectrum
GBM NaI
GBM BGO
LAT
100GeV
10KeV
100MeV
51
Gamma Ray Bursts
Highest-energy emission from bursts is intriguing
EGRET detected a 20 GeV photon 75 minutes after
the start of a burst
Hurley et al., 1994
Future Prospects GLAST will provide definitive
information about the high energy behavior of
bursts LAT and GBM together will measure
emission over gt7 decades of energy. Place your
bets on TeV burst detections!
52
GRB941017

• Gonzalez et al.

Compare data from EGRET and BATSE Distinct
high-energy component has different time
behavior. What is the high-energy break and total
luminosity? Need GLAST data! Learn important
lessons from the past.
-18 to 14 sec 14 to 47 sec 47 to 80 sec
80-113 sec 113-211 sec
53
Gamma-Ray Bursts at High Energy

• Little is known about GRB emission in the gt 50
  MeV energy regime.
• EGRET detected 5 high-energy bursts, but
  suffered from
• Small field of view (40), so few bursts were
  detected
• Small effective area (1000 cm2), so few detected
  photons per burst
• Large deadtime (100 ms/photon), so few prompt
  photons were detected
• Prompt GeV emission with no high-energy cutoff
  (combined with rapid variability) implies highly
  relativistic bulk motion at source ? gt 102
  103

Extended or delayed GeV emission may require more
than one emission mechanism, and remains one of
the unsolved problems.
54
GLAST GRB
MOC -gt ISOC -gtGSSC
TDRSS

• BATSE like population of bursts
• Spectrum Extrapolated at high energies

1/month with good localization(lt0.1 deg)

• 40-60 LAT burst/yr year
• 1/month with good statistics
• 1/yr 1000 counts

55
GBM

• provides spectra for bursts from 10 keV to 30
  MeV, connecting frontier LAT high-energy
  measurements with more familiar energy domain
• provides wide sky coverage (8 sr) -- enables
  autonomous repoint requests for exceptionally
  bright bursts that occur outside LAT FOV for
  high-energy afterglow studies (an important
  question from EGRET)
• provides burst alerts to the ground.

Simulated GBM and LAT response to time-integrated
flux from bright GRB 940217 Spectral model
parameters from CGRO wide-band fit 1 NaI (14 º)
and 1 BGO (30 º)
56
Predictions
GRB detectable by GLAST LAT
57
Predictions
58
Predictions
59
Predictions
60
Burst Advocate
61
GBM
GCN Notices
Alert messages
LAT
10-15s
10-15s
Alert messages (1Alert lt10 Update 1Closeout)
T0
(Ground Analysis 10)
Paging System
Real Time Operations Found special GRB DS /
BA / Other (Telecon)
10-15s
Password Protected web page
1hr (30 Goal)
1st GCN Circular
ASP Automated Science Processing HSP Human
Science Processing
62
Pool of burst advocate

• Pool of burst advocate (was two per days in
  oktober test)
• Now making the one for the LaunchEarlyOrbit 55
  days Sim

63
our first simulated experience
Delivery of alerts via e-mail (GCN-Like) LAT
notices GBM notices Swift notice
GRB090103a
Burst Advocate awake Call a EVO meeting
We met in EVO (20 after the burst), Evaluation
of the alerts messages First Circular (90 after
the burst)
A wiki page for this burst was made available,
tracking all the notices, and all the analysis
LAT Downlink (3hr after) ASP automatically runs
on received notice ASP also searches for other
burst
We met in a 2nd EVO (6hr after the burst), LAT
analysis done Issue reported by the Duty
Scientist
B/A - D/S interaction must be improved Usually
only 2 meetings should be needed
GBM data available (20 hr after the burst)
All the analysis into confluence
We met in a 3rd EVO (25hr after the burst), LAT
GBM analysis done 2nd Circular Sent
64
Summary

• GLAST, together with the other gamma-ray
  observatories, will address many important
  questions
• How do Natures most powerful accelerators work?
• What are the unidentified sources found by EGRET?
• What is the origin of the diffuse background?
• What is the origin of cosmic rays?
• What is the high energy behavior of gamma ray
  bursts?
• When did galaxies form?
• What else out there is shining gamma rays? New
  sources (e.g., galaxy clusters)? Are there
  high-energy relics from the Big Bang? Are there
  further surprises in the poorly-measured energy
  region?
• Huge leap in key capabilities enables large menu
  of known exciting science and large discovery
  potential.
• Part of the bigger picture of experiments at the
  interface between particle physics and
  astrophysics.

Much to do join the fun!!
65
Conclusions

• The GLAST LAT is the largest satellite g-ray
  observatory for the next decade
• The Astrophysics-HEP partnership provided state
  of the art detectors for a high performing
  instrument
• The INFN-ASI partnership was extremely successful
  in constructing, testing and delivering the LAT
  Tracker
• The INFN-ASI community has a leading role for the
  LAT calibration and operation and science
  exploitation of the mission
• Launch scheduled 29-may-2008

66
GLAST launch 5/2008

• GLAST is the next generation satellite g-ray
  observatory
• prime physics on a wide range of topics,
  including DM and new physics searches, is
  expected (10 active science working groups)
  thanks to excellent instrument performance
• GLAST put together the HEP and astrophysics
  communities to build a high performance detector
  for a first rank physics program hopefully the
  shared scientific interest on the nature of Dark
  Matter will see revolutionary discoveries