SLAC DoE Review June 14-16, 2005

GLAST Large Area Telescope OverviewElliott BloomSLAC - KIPACStanford University

GLAST Large Area Telescope:GLAST Large Area Telescope:

IntroductionGamma-ray Large Gamma-ray Large Area Space Area Space TelescopeTelescope

Why studyWhy study’s?’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 2007

5-year mission (10-year goal)

Large Area Telescope (LAT)

spacecraft partner: GLAST Burst Monitor (GBM)

Generic Pair Conversion TelescopeGeneric Pair Conversion Telescope

CalorimeterCalorimeter (energy measurement)(energy measurement)

Conversion Conversion foilsfoils

e+ e-^̂̂̂̂̂̂̂ ^̂^̂

^̂ ^̂̂̂̂̂

Particle Particle tracking tracking detectorsdetectors

Charged particle Charged particle anticoincidence anticoincidence shieldshield

Principle of OperationPrinciple of Operation

LAT

Overview of LATOverview of LAT• Precision Si-strip Tracker (TKR) Precision Si-strip Tracker (TKR)

~80 m2 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 Segmented Anticoincidence Detector (ACD)Detector (ACD) 89 plastic scintillator tiles. Reject background of charged cosmic rays; segmentation removes self-veto effects at high energy.

• Electronics System Electronics System Includes flexible, robust hardware trigger and software filters.

Systems work together to identify and measure the flux of cosmic gamma Systems work together to identify and measure the flux of cosmic gamma rays with energy 20 MeV - >300 GeV.rays with energy 20 MeV - >300 GeV.

e+ e–

Calorimeter

Tracker

ACDGrid

Large Area Telescope (LAT)Large Area Telescope (LAT)

e+ e–

Calorimeter

Tracker

ACDGrid

• 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 Large Area Telescope:

GLAST OrganizationGamma-ray Large Gamma-ray Large Area Space Area Space TelescopeTelescope

GLAST MISSION ELEMENTSGLAST MISSION ELEMENTS

GN

HEASARCGSFC

-

-

DELTA7920H •

White Sands

TDRSS SNS & Ku

LAT Instrument Science Operations

Center

GBM Instrument Operations Center

GRB Coordinates Network

• Telemetry 1 kbps•

-•

S

Alerts

Data, Command Loads

Schedules

Schedules

ArchiveMission Operations Center (MOC)

GLAST Science Support Center

• sec•

•

•

GLAST Spacecraft

Large Area Telescope& GBMGPS

GLAST MISSION ELEMENTS

Get final version from Rob.

GLAST is an International MissionGLAST 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

FranceSweden Italy

USA Japan

LAT CollaborationLAT Collaboration

total USCollaboration members: 161 75

Members: 77 43Affiliated Sci. 67 28Postdocs: 17 4

SLAC: Members: 15Affiliated: 2Postdocs: 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 Current LAT Organization Chart for LAT Construction and TestConstruction and Test

Principal InvestigatorP. Michelson

Instrument ScientistS. Ritz

Senior Science Advisory CommitteeN. Gehrels

Collaboration Science Team

Project ManagerL. Klaisner

D. Horn, DeputyP. Drell, Deputy

Instrument Science PerformanceS. Ritz, W. Atwood

D. Horn

TrackerR. Johnson

ACDD. Thompson

DAQ & FSWG. Haller

Integration &TestE. Bloom

SASR. Dubois

MechanicalM. Campell

ISOCR. Cameron

CalorimeterN. Johnson

EPOL. Cominsky

Chief of ElectronicsG. Haller

System EngineeringP. Hascall

Mission AssuranceJ. Cullinan

ProductionB. Esty

Project ControlsT. Boysen

P. Drell*

AdministrationD. Nicholson

L. Klaisner

ITAR ManagementS. Williams

Staff PhysicistT. Himel

Design Int. & Anal.M. Nordby

Deputy Principal InvestigatorScience Operations

S. Ritz

Deputy Principal InvestigatorInstrument/ Observ. Operations

N. Johnson

Staff PhysicistC. Young

Inst/Observatory Pre-launch Operations N. Johnson

* Recently stepped down

LAT Organization Chart: Science Operations PhaseLAT Organization Chart: Science Operations PhaseCurrent 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:GLAST Large Area Telescope:

LAT PerformanceGamma-ray Large Gamma-ray Large Area Space Area Space TelescopeTelescope

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 < 10 GeV, and >100 at higher Results in factor > 30 improvement in sensitivity below < 10 GeV, and >100 at higher energies.energies.

• Much smaller deadtime per event (27 sec, factor ~4,000 better than EGRET - 0.1 s)

• No expendableslong mission without degradation (5 year requirement , 10 year goal).

GLAST LAT High Energy CapabilitiesGLAST LAT High Energy Capabilities

Cygnus region (15x15 deg)

Dramatic Improvement in PDramatic Improvement in Point oint SSpreadpread F Functionunction and and Source Localization over EGRETSource 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 modeHigh energy source sensitivity: all-sky scan mode

100 sec

1 orbit**

1 day^̂

^“rocking” all-sky scan: ^“rocking” all-sky scan: alternating orbits point alternating orbits point above/below the orbit planeabove/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 *zenith-pointed

GLAST Large Area Telescope:GLAST Large Area Telescope:

LAT ScienceGamma-ray Large Gamma-ray Large Area Space Area Space TelescopeTelescope

Connections:Connections: Quarks to the Cosmos Quarks to the CosmosThe Universe as a LaboratoryThe 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 GLAST addresses a broad science menu of interest to both the High Energy Particle Physics and High to both the High Energy Particle Physics and High

Energy Astrophysics communities.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 Recommended by the National Academy of Sciences in their 2000 decadal study as the highest priority mid-sized mission2000 decadal study as the highest priority mid-sized mission

* Connections related

GLAST is on the trail of Dark MatterGLAST is on the trail of Dark Matter SLAC

User’s Community

KIPAC Stanford University

GLAST Team

Galaxy ClustersX-ray measurements

Spiral GalaxiesRotation Curves

Evolution of UniverseCDM Cosmology

Big Bang CMB

Baryonicmatter

Dark matter

Totalmatter

- There Are Signs of Dark Matter Everywhere -- There Are Signs of Dark Matter Everywhere -

Cosmology: Origin of Extragalactic Diffuse RadiationCosmology: 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/0405235-040605

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)

E2 d

J/dE

(keV

/(cm

2-s

-keV

-sr)

EGRET

steep-spectrum quasars

Seyfert II galaxies

Seyfert I galaxies

Type 1a Supernovae

discovery spacediscovery space• blazars• normal galaxies• cluster mergers• primordial diffuse• new physics

Also see: de Boer, Astro-ph/0412620 (2004)“EGRET data show an intriguing hint of DM annihilation”. Appears as an excess of diffuse galactic rays. Mwimp ~ 50 – 100 GeV.

Halo Dark Matter Search with GLASTHalo Dark Matter Search with GLAST• Wimp Annihilations in halo Clumps (b >|10| deg):

– gamma continuum from pions• very hard spectrum @ ~100 MeV (~ E0)

– 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 dimensionsDiscovery 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

( ~ 109 years) to nn, e+e-, and

fKK is the fraction of SN energy emitted as KK gravitons. Authors calculate potential GLAST limit of FKK < 10-7 for this source for n = 2, and < 0.5x10-7 for n =3.

Discovery Potential: Large Extra DimensionsDiscovery Potential: Large Extra DimensionsConstraints from EGRET observations (Hannestad & Raffelt 2003;Cassé, et al,

Phys.Rev.Lett. 92 (2004) 111102): 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, ~ 7x108. 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:GLAST Large Area Telescope:

Integration and TestOverview

Gamma-ray Large Gamma-ray Large Area Space Area Space TelescopeTelescope

Particle TestOrganization of I&T – OverviewOrganization 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

SoftwareScience Verification

Analysis and Calibration (SVAC)

Management

Particle Test

I&T Operations 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 StatusGLAST LAT Technical Status

14 CAL modules at SLAC.

ACD being tested at GSFC. Delivery to SLAC in July.

7 Trackers @ SLAC.~80m2 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 GratificationAlmost Instant 4-Tower Gratification(SVAC)(SVAC)

A Two-Tower Gamma Ray CandidateA Two-Tower Gamma Ray Candidate

GLAST Large Area Telescope:GLAST Large Area Telescope:

Science Analysis Software(SAS)

Gamma-ray Large Gamma-ray Large Area Space Area Space TelescopeTelescope

LAT Data ChallengesLAT 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 2006. More ambitious goals, incorporate lessons learned from DC1. ~One simulated month.

– DC3 in 2007. Support for flight science production.

DC ComponentsDC 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 http://www-glast.slac.stanford.edu/software/Workshops/Feb04DC1CloseOut/coverpage.htm

The Simulated DC1 SkyThe Simulated DC1 SkyExtragalactic diffuse

Galactic diffuse

EGRET 3EG

Fiddling 3C273/279

Our Sky

R.Dubois

GLAST Large Area Telescope:GLAST Large Area Telescope:

Schedule and ConclusionsGamma-ray Large Gamma-ray Large Area Space Area Space TelescopeTelescope

•The GLAST mission is completing the fabrication phase and is well into integration.

•LAT, GBM, and spacecraft assembly complete by January 2006.

•Delivery of the LAT and GBM instruments for observatory integration spring 2006.

•Observatory integration and test spring 2006 through summer CY07.

•Major scientific conference, the First GLAST Symposium, being planned for 2006.

•Launch in August 2007… Science Operations begin within 60 days … Join the fun!

THE LOOK AHEADTHE LOOK AHEAD

200720062005

Fabrication

Instrument & S/C I&T

Observatory I&TLaunch

Extra Slides FollowExtra Slides Follow

33rdrd EGRET Catalog EGRET CatalogGLAST Survey: ~300 sources (2 days)GLAST Survey: ~300 sources (2 days) GLAST Survey: ~10,000 sources (2 years)GLAST Survey: ~10,000 sources (2 years)

AGN - blazars

unidentified

pulsars

LMC