Science Capabilities - Summary

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Science Capabilities - Summary
100 s 1 orbit 1 day
200 ? bursts per year ? prompt emission
sampled to gt 20 µs AGN flares gt 2 mn ? time
profile ?E/E ? physics of jets and
acceleration ? bursts delayed emission all
3EG sources 80 new in 2 days ? periodicity
searches (pulsars X-ray binaries) ? pulsar
beam emission vs. luminosity, age, B 104
sources in 1-yr survey ? AGN logN-logS, duty
cycle, emission vs. type, redshift,
aspect angle ? extragalactic background light
(? IR-opt) ? new ? sources (µQSO,external
galaxies,clusters)
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Active Galactic Nuclei - Cosmic Linear
Accelerator -

• Synchrotron and inverse Compton radaition emitted
  by ultra relativistic flow of electron-positron
  plasma along the axis of the distant rotating
  super-massive black hole (Quasar PKS 0637-752)

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Active Galactic Nuclei New Way to Study

• Measure the spectra above 100 MeV from AGN
  (based on blazar logN-logS extrapolations)
• Explore low-energy spectrum where many AGN have
  peak emission
• Monitor variability and notify flares
• Study of AGN evolution and history of
  star-forming activity
• Overlap with ground-based gamma-ray observations

Study of time correlation Btwn X-ray and g-ray.
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Active Galactic Nuclei Time Variability
GLAST monitors all-sky continuously with high
sensitivity, detects many AGN flare-ups before
anyone else, and records their entire history for
the first time.
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Active Galactic Nuclei Spectrum
GLAST will detect 3000 AGNs, reaching to z4-5.
Thus we will detect cosmological evolution of
AGNs and their role in the galaxy formation.
Extragalactic IR-UV background light (EBL) by
star-forming activity absorbs high energy
gamma- rays by gg gt ee-. Thus GLAST will
measure history of star-formation in z1-5.
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Accelerating Shock Fronts- Cosmic Random Phase
Synchrotron -

• Super Nova Remnant 1006 seen by ASCA (X-ray
  band)
• Image of synchrotron radiation by high energy
  (200TeV) electrons in the
• accelerating shock front in SN1006

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Accelerating Shock Fronts- Cosmic Random Phase
Synchrotron -

• Super Nova Remnant 1006 seen by Cangaroo (TeV
  gamma-ray)
• Image of photons (CMB) scattered by high
  energy (200TeV) electrons
• in the accelerating shock front of SN1006.

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Pulsars (Rotating Neutron Stars)- Cosmic
Betatron -

• Synchrotron emission (X-ray) by high energy
  electrons (100GeV) from the neutron stars
  magnetosphere (Magnetic induction Pulsed)
• Synchrotron emission (X-ray) by high energy
  electrons (100TeV) from the nebula around the
  neutron stars magnetosphere (Accelerating shock
  front Unpulsed)

The bell-shaped synchrotron nebula around the
Crab pulsar (the small dot at the center of the
opening of the bell-shaped nebula). A
string-like flow of electrons along its rotation
axis is also visible.
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Pulsars Radio-Quite Brothers (NS)

• Until recently, all pulsars have been discovered
  in Radio Band, with one exception of Geminga.
• In the past 5 years several pulsars have been
  discovered in X-ray. They are generally very
  weak in Radio Band. Many
  radio-quiet pulsars to be discovered
• We now expect to find many radio-quiet pulsars.
  We can see throught the Galaxy with gamma-rays
  but not with radio wave. So we will study
  distribution of pulsars (ie. NSs) in the Galaxy.
  History of star-formation activity
  in our Galaxy.

Gemingas pulse profile by EGRET
Radio-loud
GLAST Radio-quiet
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Gamma-ray Bursts

• LAT
• Capture gt 25 of GRBs in LAT FOV (2 sr or more)
• Deadtime of lt 100 msec per event
• Spectral resolution lt 20, especially at energies
  above 1 GeV
• GBM
• Monitor energy range 10 keV - 20 MeV
• Monitor FOV of 8 sr (shall overlap
• that of the LAT)
• Notify observers world-wide
• Recognize bursts in realtime
• Determine burst positions to few degree
• accuracy
• Transmit (within seconds) GRB
• coordinates to the ground
• Re-point the main instrument to GRB
• positions within 10 minutes

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Gamma-Ray Bursts Wide Energy Coverage

• Cover the classical gamma-ray band where most of
  the burst photons
• are emitted by GLAST Gamma-ray Burst Monitor
  (GBM)
• Monitor all of the sky visible from Low-Earth
  Orbit ( 10keV-30MeV)
• Monitor 40 of the sky visible from LEO
  (20MeV-500GeV)
• Identify when and where to re-point the
  spacecraft to optimize
• observations and notify other observers

Simulation Spectrum of an intense GRB by GLAST
10 keV
10 GeV
10 MeV
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Gamma-Ray Bursts at gt 20 MeV

• EGRET discovered high energy GRB afterglow
• only one burst
• dead time limited observations
• GLAST will observe many more high energy
  afterglows
• strong constraint to GRB models

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Gamma-Ray Bursts at gt 20 MeV

• Spatial
• Monitor gt 2 sr of the sky at all times
• Localize sources to with gt 100 photons to lt 10
  arcmin
• Temporal
• Perform broad band spectral studies and search
  for spectral structure
• Find correlation between 10 keV - 20 MeV and gt 20
  MeV photons
• Determine characteristics of gt 20 MeV afterglow

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Gamma-Ray Bursts Correlation btwn X-ray and g-ray
Standard wisdom about GRB is the more energetic,
the closer to the central energy source. GLAST
measures both in X-ray/soft g-ray (GBM) and high
energy g-ray (LAT), arrowing to study temporal
correlation between them.
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Cosmic Ray Interaction with Inster Stellar Matter
(1)
Inner Galaxy (llt60o,blt10o) by EGRET. Elect.
Brems., Inv. Compton, Isotr. Diff., and N-N
int. (pi-zero).
SNR IC443 by EGRET and GLAST (simulation). Elect.
Brems., Inv. Compton, and N-N int.
(pi-zero). Note that electron contri. dominates
in SNRs.
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Cosmic-Ray Flux and Composition in SNRs, GMCs,
Galactic Plane/Bulge, Nearby galaxies, Nearby
Clusters

• Separation of electron contribution (brems. and
  IC) and proton contribution (pi-0)
• is important. Association of SNRs, history of
  the galaxy or the cluster
• Even in galactic level, the total energy of
  cosmic-ray is non-negligible. It can be very
  important in cluster level.

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Cosmic Ray Interaction with Inster Stellar Matter
(2)
Gamma Cygni SNR Pulsar, SNR, and cosmic-ray
interaction with ISM
Measurement on cosmic-ray proton and electron
fluxes
Radio image of Molecular H line (21cm)
EGRET image
GLAST image (simulation)
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Cosmic Ray Contents in Nearby Galaxies
GLAST will measure cosmic electron and proton
fluxes for LMC, SMC and M31
Past SN rate, past history of galaxies, stability
of galaxies
LMC by GLAST (simulation)
LMC in IR (IRAS)
LMC by EGRET
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Galactic Diffuse Emission Galaxy Simulator
Project

• Objectives
• Separate pi-zero and electron brems.
  contributions
• Determine total mass of nearby GMCs
  C/H ratio
• Galactic electron distribution SNR
  association?
• Galactic arm structure What are between
  arms?
• Correlation with radio, X hard-X observations
• Galactic magnetic field strength and large scale
  structure
• Determine total amount of cold dark baryonic
  matter

Giant Molecular Clouds in Cygns region (galactic
arm structure?)
Pi-zero flux measurement by GLAST will determine
the total mass in the GMCs and their C/H.
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Schedule of the GLAST Mission
Calendar Years
2010
2000
2002
2003
2005
2001
2004
Inst. Delivery
Launch
M-CDR
I-CDR
SRR
NAR
PDR
Formulation
Implementation
Ops.
Build Test Engineering Models
Build Test Flight Units
Inst. IT
Inst.-S/C IT
Schedule Reserve
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Thank you for attention. Please wait for launch
in 2005