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  • 3:37 PM, Sunday, 24 Oct 2021

Course Dual Degree (B. Tech + M.S / M.Tech)
Semester Electives
Subject Code ESA468
Subject Title Accretion Physics


Introduction: Accretion as a source of energy – observational consequences. Accretion in binary system: Introduction – Interacting binary system – Roche lobe overflow – Disk formation – Viscous torque – The α disk viscosity – Low and high-mass X-ray binaries. Accretion disk (thin accretion disk) Theory: Basic concepts – Structure of thin disk – The emitted spectrum of steady α-disk – Time dependence and stability – the thermal disk instability model (dwarf novae) – wind accretion – Disk around young stars – confrontation with observations. Accretion on to compact object: Boundary layers – Accretion on to magnetized neutron star and white dwarf – accretion column – accretion on to black hole. Accretion disks in AGN: AGN models – Radio, millimeter and infrared emission – optical, UV and X-ray emission – broad and narrow line region – Extended and compact radio sources – The Blandford-Znajek model. Thick discs: The limiting luminosity – accretion tori – self-gravitating disks and their stability – astrophysical implication. Accretion flows: The governing equations – A unified description of steady flow – advection- dominated flows – general transonic accretion solution in presence of heating and cooling.

Text Books

1. Accretion Power in Astrophysics by Juhan Frank, Andrew King, Derek Raine (Cambridge University Press)

2. Accretion Processes in Star Formation by Lee Hartmann (Cambridge Astrophysics)

3. Theory of Transonic Astrophysical Flow by Sandip K. Chakrabarti (World Scientific)


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