Astrophysics of the High-Energy Universe 10-14 August 2015 Instituto Nacional de Astrofísica Optica y Electrónica (INAOE) Puebla, Mexico Charles Dermer (Naval Research Laboratory) Dr. Charles D. Dermer Naval Research Lab, Code 7653 Washington, DC 20375‐5352 USA 202‐767‐2965 [email protected]Lecture 1. The High-Energy Universe The most energetic and powerful radiations in nature are made by particles accelerated through Fermi processes in black‐hole jets powered by rotation.
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Astrophysics of the High-Energy Universe - INAOE€¦ · Telescopes (MAGIC) (Canary Islands; 2004) 5. Fermi Gamma-ray Space Telescope ( 2008) 6. High Altitude Water Cherenkov (HAWC)
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Astrophysics of the High-Energy Universe10-14 August 2015
Instituto Nacional de Astrofísica Optica y Electrónica (INAOE)Puebla, Mexico
Charles Dermer (Naval Research Laboratory)
Dr. Charles D. DermerNaval Research Lab, Code 7653
Precision Si-strip Tracker (TKR) Measure the photon direction; gamma ID. pitch = 228 m, 8.8×105
channels, 18 planes
Hodoscopic CsI Calorimeter (CAL) Measure the photon energy; image the shower.
Segmented Anticoincidence Detector (ACD) Reject background of charged cosmic rays; segmentation removes self-veto effects at high energy.
Electronics System Hardware trigger, software filters
Systems work together to identify and measure the flux of cosmic gamma rays with energy 20 MeV - >300 GeV
Calorimeter
Tracker
ACD
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Operations and observing modes
Almost all observations in survey mode - the LAT observes the entire sky every two orbits (~3 hours), each point on the sky receives ~30 mins exposure during this time.
– 39 deg rocking angle to Sept 2, 50 deg after September 3, 2009. Very high ontime! , Autonomous Repointing
– In response to bright GBM-detected GRBs, LAT-triggered GRBs Dedicated Pointings
– Crab flares, bright blazars, -ray novae
LAT sensitivity on 4 different timescales: 100 s, 1 orbit (96 mins), 1 day and 1 year
Optical transients– Meteors, Comets– Supernovae
Hammer-Aitoff Projection of the Full Sky
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Gamma-ray transients– Blazars– Gamma Ray Bursts
All-sky/Large field-of-view coverage provided by Fermi and HAWC
Large Field-of-View vs. Pointing (Narrow-Field) InstrumentsSources of Background
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The Fermi LAT (3 month) Sky
Fermi >1 GeV 5 Year Sky Map
Fermi: >10 GeV Skymap
Calibration and AnalysisCatalogsGalactic SourcesDiffuse and Molecular Clouds (and Other Galaxies) Sources in the Solar SystemBlazars and other AGNsGamma Ray BurstsDark Matter and New Physics
HAWC, successor of Milagro, is a large‐field‐of‐view TeV telescope.
Fermi ‐ray sky
• >100 MeV, 36 months• Galactic ‐ray glow:
accelerated particles meet target gas and photons
• ~80% of the emission is diffuse
• Transient and flaring sources
• Normal and ms pulsars• Blazars• GRBs• Other ‐ray galaxies• Unidentified sources
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Sample of Early Discoveries from Fermi
W44
Crab Nebula
GRB090902All sources Blazars
Populations
3C279
Energy Units
Microphysical quantities related to electron mass and energy
2cmE e
F Spectra: Point Sources
Photon flux:
Energy flux (density):
Flux density F in Jansky1 Jy = 10-23 erg cm-2 s-1 Hz-1
Energy Flux:
F in Jansky-Hertz or erg cm-2 s-1
Notation:
Blazar 3C 454.3
dAdtddN
)(
)(
z = 0.858
Ned Wright’s cosmology calculator z = 0.859 dL =1.7e28 cm 13.7 Gyr *c = 1.3e28 cm
SUN
Solar constant: 1400 Watt/m2
1.4x106 erg/s‐cm2
Earth‐Sun distance: (1 AU): 1.5x1013 cm
Solar luminosity: 4x1033 erg/s
Solar mass: 2x1033 gm
Macrophysical quantities related to Sun
Optical Energy Fluxes
25th magnitude star has energy flux 10-15 erg cm-2 s-1