1 Gamma-Ray Astronomy with GLAST May 24, 2008 Toby Burnett WALTA meeting
2 GLAST meets its spacecraft, last December GLAST meets its launch vehicle (last week)
3 Launch: from Cape Canaveral – June 3, 2008 We are #332 WALTA meeting
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GLAST already on MySpace! 5WALTA meeting
But what is gamma-ray astronomy? WALTA meeting6 relevant names: mass charge particle cosmic ray proton muon photon x-ray gamma ray radio wave visible light ultraviolet infrared wave wave length frequency fluxspectrum telescope magnetic field energyJoule (J) electron volt (eV) AAA battery kilowatt hour gallon of gas
The cosmic ray spectrum WALTA meeting7 Flux Energy Questions: 1.Which astronomical objects are the origin of cosmic rays? 2.Above the “Knee”, can we locate the origins? astronomy possible here?
Astronomy with photons WALTA meeting8 Green: E =2.5 eV =500 nm wave-likeparticle-like
The atmosphere matters! WALTA meeting9
Telescopes & particle detectors WALTA meeting10 e+e+ e–e– calorimeter (energy measurement) particle tracking detectors conversion foil anticoincidence shield Pair-Conversion Telescope WALTA meeting Optical telescope (SDSS): A fancy camera with a CCD photon detector Schematic for a gamma- ray detector
11 GAP! GLAST ( Mike Turner 1989 ) WALTA meeting
12 log 10 (E/1 MeV) E*flux, (m -2 s -1 ) galactic protons He, CNO Galactic electrons Albedo gamma secondary protons secondary e ± WALTA meeting
LAT: 20 MeV – >300 GeV GBM: 10 keV – 25 MeV 13 Large Area Telescope (LAT) GLAST Burst Monitor (GBM) An International Science Mission Large Area Telescope (LAT) GLAST Burst Monitor (GBM) Spacecraft (General Dynamics WALTA meeting
Precision Si-strip Tracker 18 XY tracking planes. Single-sided silicon strip detectors (228 m pitch) Measure the photon direction; gamma ID. Hodoscopic CsI Calorimeter Array of 1536 CsI(Tl) crystals in 8 layers. (8 X 0 ) Measure the photon energy; image the shower. Segmented Anticoincidence Detector (ACD) 89 plastic scintillator tiles. Reject background of charged cosmic rays; segmentation removes self-veto effects at high energy. Electronics System Includes flexible, robust hardware trigger and software filters. WALTA meeting14 Calorimeter e+e+ e–e– ACD Tracker 1.7 m
15 Galactic center 3C279 (blazar) Vela ( radio pulsar) Crab (radio pulsar) Geminga (radio-quiet pulsar) PKS (blazar) Isolated neutron star? SN remnant? Point things: near and far Diffuse things: CR interactions in matter Orion Cloud LMC EGRET all-sky survey (E>100 MeV) Extragalactic diffuse WALTA meeting
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GLAST’s view of the sky 17WALTA meeting
GLAST sources found (simulation) WALTA meeting18