The Gammaray Large Area Space Telescope GLAST and Your Favorite Topic

1
The Gamma-ray Large Area Space Telescope (GLAST)
and Your Favorite Topic
Author(Institution), Author(Institution) on
behalf of the GLAST Mission Team
Abstract The Gamma-ray Large Area Telescope
(GLAST) is a satellite-based observatory to study
the high-energy gamma-ray sky. The Large Area
Telescope, the main instrument, is a
pair-conversion telescope which will survey the
sky in the energy range 20 MeV to greater than
300 GeV. The LATs wide field of view (gt2 sr),
large effective area and low deadtime combine to
provide excellent high-energy gamma-ray
observations of GRB. To tie these frontier
high-energy observations to the better-known
properties at lower energies, a second
instrument, the GLAST Burst Monitor (GBM) will
provide important spectra and timing in the 8 keV
to 30 MeV range. Upon detection of a GRB by the
LAT or the GBM, the spacecraft can autonomously
repoint to keep the GRB location within the LAT
field of view, allowing high-energy afterglow
observations. We describe how the instruments,
spacecraft, and ground system work together to
provide observations of gamma-ray bursts from 8
keV to over 300 GeV and provide rapid
notification of these observations to the wider
gamma-ray burst community. Complementarity and
opportunities for cooperation with Swift are also
discussed briefly.

• GRBs and GLAST
• GeV burst observations are important closer to
  underlying GRB engine energy scale and observable
  to high redshift. Little is known about the
  high-energy behavior of bursts. The few results
  from EGRET are tantalizing, making GLAST
  observations even more important
• observations of the prompt phase from 8 keV to
  gt300 GeV (gt7 decades in energy!)
• GBM will detect 200 GRB/year, with 60 of these
  within the canonical LAT FoV.
• autonomous repoint capability will allow
  high-energy afterglow studies
• GRB locations determined onboard by either the
  GBM (several degrees) or the LAT (sub degree),
  depending on burst properties, are sent in near
  real time to GCN.

• Swift and GLAST
• Joint observations of bursts by both Swift and
  GLAST will be extremely valuable as the two
  missions provide fundamentally different, but
  complementary, observations of GRB.
• BAT, GBM and LAT will provide observations of
  the prompt phase over a huge energy range
• The GLAST LAT and Swift XRT and UVOT will
  provide afterglow observations at optical, X-ray
  and high energy gamma-ray wavebands.
• Assuming a Swift GRB detection rate of 100
  GRB/year, if the GLAST and Swift pointing
  directions are uncorrelated, then we expect 20
  Swift-detected GRBs/year to occur within the LAT
  FoV. The fraction of these actually detected by
  LAT, and their characteristics, are important
  questions for GLAST to answer.

• GLAST Science
• 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 huge leap in capabilities.
• GLAST will have a major impact on many topics,
  including
• 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 sources
• Discovery! Particle Dark Matter? Other relics
  from the Big Bang? Testing Lorentz invariance.
  New source classes.
• Important overlap and complementarity with the
  next-generation ground-based gamma-ray
  observatories.