Bondi/Hoyle and Shakura/Sunyaev - Max-Planck-Institut für ...

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<strong>Shakura</strong>/<strong>Sunyaev</strong> accretion • Newtonian mechanics, central potential for gravity • Hydrodynamic flow, axisymmetric disk geometry, stationarity ⇒ 1D problem • Disk is stabilized by centrifugal forces • Self-gravitation of accreted matter is neglected • Non-adiabatic, viscous fluid • Simple radiative transfer 15
Disk accretion: General features • Accreted matter may have angular momentum ⇒ high angular velocity uφ near the CO • Accretion disk consists of rings of nearly Keplerian orbits • lKepler ∝ √ r ⇒ inward motion only possible through transport of angular momentum (slow) • Thus matter has much time to radiate binding energy away • Much more efficient at generating luminosity than spherical accretion! • Viscosity has two functions here: ⋆ Transport of angular momentum ⋆ Heat generation 16
Page 1 and 2: Accretion: Bondi/Hoyle and Shakura/
Page 3 and 4: Literature • This talk is based o
Page 5 and 6: Accretion onto compact objects •
Page 7 and 8: Models of accretion • Analytical
Page 9 and 10: 2. Spherical accretion 8
Page 11 and 12: Flow description • 1D radial flow
Page 13 and 14: • u(r) at small radii: free-fall
Page 15: 3. Disk accretion 14
Page 19 and 20: Sketch of a thin accretion disk 18
Page 21 and 22: Angular momentum conservation • M
Page 23 and 24: Vertical momentum conservation •
Page 25 and 26: Viscosity law • Several physical
Page 27 and 28: Radiative transport • Transport f
Page 29 and 30: Structure of the solution • The s
Page 31 and 32: 4. General relativistic torus accre
Page 33 and 34: The torus (thick disk) model • As
Page 35: Summary • Accretion is inflow of

Bondi/Hoyle and Shakura/Sunyaev - Max-Planck-Institut für ...

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