Colliders To Cosmic Rays, Lake TahoeFebruary 25 – March 1, 2007

GLAST Large Area Telescope OverviewElliott BloomSLAC - KIPACStanford University

Representing the GLAST Collaboration

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 (z~700). 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 30 MeV

Launch: Fall 2007

5-year mission (10-year goal)

LEO @ 550km, ~26o

Large Area Telescope (LAT)

spacecraft partner: GLAST Burst Monitor (GBM)

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 Detector Segmented Anticoincidence Detector (ACD)(ACD) 89 plastic scintillator tiles and 8 ribbons. 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 in flight software.

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

16 towers-TKR+CAL+DAQ

GLAST MISSION ELEMENTSGLAST MISSION ELEMENTS

GN

HEASARCGSFC

-

-

DELTA7920H •

White Sands

TDRSS SNS & Ku

LAT Instrument Science Operations

Center (SLAC)

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

GLAST LAT CollaborationGLAST 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

Cooperation between NASA and DOE, with key international contributions from

France, Italy, Japan and Sweden.

Managed at Stanford Linear Accelerator Center (SLAC).

Principal Investigator: Principal Investigator: Peter MichelsonPeter Michelson (Stanford & SLAC)

~225 Members (includes ~80 Affiliated Scientists, 23 Postdocs,

and 32 Graduate Students)

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 the essentially 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 expendables long 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 to ~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 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?

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

Gammas from linesGammas from lines

For Line, energy = WIMP mass For WIMP masses > MZ /2 can also have Z0 line

Measurement of line branching fractions would constrain particle theory

γ

γ

?

time

γ

Z0

?

Branching fractions are in the range 10-2 - 10-4

Where should we look for WIMPs with GLAST?Where should we look for WIMPs with GLAST?

• Galactic center

• Galactic satellites

• Galactic halo• Extra-galactic

The Galaxy Shinning in High Energy Gammas The Galaxy Shinning in High Energy Gammas from the Annihilation of Dark Matterfrom the Annihilation of Dark Matter

http://glast.gsfc.nasa.gov/science/symposium/2007/program.html

GLAST LAT Mounted toSpace Craft at General Dynamics in Gilbert, AZ. First communication with MOC on February 25, 2007.

• Major scientific conference, the First GLAST Symposium, held February 1-4, 2007 at Stanford University.

• Observatory integration and test through late summer 2007.

• Launch in late fall 2007… Science Operations begin within 60 days

THE LOOK AHEADTHE LOOK AHEAD

200720062005

Fabrication

Instrument & S/C I&T

Observatory I&T Launch