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 binarie s. Accretion disk (thin accretion disk) Theory: Basic concepts --- Structure of thin disk --- The emitted spectrum of steady α -disk --- Time dependence and stability --- the the rmal disk instability model (dwarf novae) --- wind accretion --- Disk around young stars --- confrontation with observations.

Introduction : How radiation affects the flow of ma tter -- Cooling, Heating, Momentum transfer, Matter density variation due to annihilation/pair-p roduction. Review of gas dynamics: Ideal fluids, Transport terms - Viscosity & heat conducti on, Sound waves, Shocks - Rankine-hugoniot relations. Review of radiation physics : Intensity, Flux, Energy density, Stress tensor, Transport equations, Diffusion approximation, Coupling terms in Euler's equations.

Imaging and detector basics - resolution, sensitivi ty, noise, dynamic range, efficiency, linearity - image formation at focal plane - Fourier transform - Deconvolution and Image reconstruction - Photography, CCD -- Large optical / IR telescopes a nd their designs - thin lens - segmented mirrors - Active optics - Designs of few upcoming l arge telescopes (eg.

The interstellar medium and its phases - dust - mol ecular clouds - virial theorem analysis. Star clusters - OB associations - T and R associations - initial mass function. Heating and cooling of clouds - cloud thermal structure - build up of mole cules - molecular transitions of H2, CO. Cloud equilibrium and stability - Jeans mass - isothermal spheres - basic magnetohydrodynamics - magnetic support - ambipolar diffusion - inside-out collapse - rotational effects.

Elements of probability theory - random variables-G aussian distribution-stochastic processes- characterizations and properties-Gauss-Markov proce sses-Brownian motion process-Gauss- Markov models - Optimal estimation for discrete-tim e systems - fundamental theorem of estimation-optimal prediction. Optimal filtering - Weiner approach-continuous time Kalman Filter-properties and implementation- steady-state Kalman Filter-discrete-time Kalman Filter- implementation-sub-optimal steady-state Kalman Filt er-Extended Kalman Filter-practical applications.

Radiation-matter interaction – Sources of high ener gy (UV-gamma rays) radiation in the universe - Detectors for high energy particles, X-r ays, gamma rays and neutrinos – Space astronomy - Elements of General Relativity - compac t stars – magnetospheric processes around neutron stars (pulsars and magnetars) – inte racting binaries – Roche potential and accretion – Shkura-Sunyaev thin disk model – accret ion phenomenology around compact objects – stellar mass black holes vs supermassive black holes – AGN phenomenology and unified scheme – Jet production and superluminal mo tion – Supernova

Occurrence and state of cosmic diffuse matter – ion ized, atomic, molecular gas and dust – heating and cooling, equilibrium phases – probes of diffuse matter (line and continuum radiations at various wavelengths) – Thermal and io nization equilibrium of HII regions – UV shielding in molecular gas – extinction/reddening/p olarization due to dust – dust heating and IR emission – star forming regions - cosmic rays and n on-thermal synchrotron emission – recombination and re-ionization of IGM – Lyman alph a forest, Mg absorption systems – Gunn Peterson effect – Heating of intracluster gas – Sun

Conservation laws – Euler’s Equations – Common Equa tions of State – Hydrostatic Equiibrium – Isothermal sphere – Virial Theorem – linear pertu rbation theory – acoustic waves – Jeans’ instability – Rayleigh Taylor instability – de Lava l nozzle - Parker wind solution – Bondi accretion – Shock waves– Sedov solution – elements of plasma physics - Debye screening – orbit theory - elements of MHD – flux freezing – Alfven waves - Langmuir oscillations –dispersion relation of electromagnetic waves propagating in plasmas- plasm a instabilities - transport phenomena