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High energy Astrophysics Mat Page Mullard Space Science Lab, UCL Revision lecture
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Revision lecture: This lecture: Quick race through the course! Intended to inspire you to look back through your notes!
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1: What is high energy astrophysics? High energy because: –Photons emitted above 100 eV (X-ray sources) –Large energy density in photon field or magnetic field, (eg X-ray binaries, pulsars) –Large amount of energy stored in gravitational field (eg Black holes) Unusually high concentrations of energy
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X-rays from stellar photospheres? Take the Sun. T=5800K XUIV R
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X-ray, -ray and radio skies
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2: The whole range of X-ray sources
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3: emission mechanisms
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4+5: accreting X-ray binaries
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accretion efficiency How much energy can we get from accretion compared to fusion? Energy released per unit mass of material accreted = GM/R Energy equivalent per unit rest mass = c 2 So we can consider the efficiency of accretion to be GM/(Rc 2 ) For a white dwarf this is ~ 1.5 x 10 -4 Fusion of hydrogen converts 0.007 of rest mass to energy so we could say this has an efficiency of 0.7%
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6: radio galaxies e.g. Faranoff-Riley 1 galaxy
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shell-like filled in Cas A Crab 7: supernova remnants
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8: AGN
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9: The X-ray background
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Coma cluster 10: Masses of hot gas
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11: Gamma-ray bursts
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Burst lightcurves
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12: Cosmic rays
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13: Gravitational waves
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14: The Galactic centre
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15: The future!
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