ABOUT THE COURSE:This course is intended to impart the introduce the students to the fascinating world of radio astronomy. Radio astronomy has developed a long way over the last century. Current and upcoming radio telescopes are not only an engineering marvel but also source of the biggest data that can be produced. Addressing the challenges of radio astronomy, we need brightest minds from every discipline. This course can be taken by a student who has no or little exposure to radio astronomy.PREREQUISITES: a prior knowledge about Fourier Transform and Optics might help.INDUSTRY SUPPORT: ISRO, Industries in Space Sector, Radio Astronomy Institutes, etc.
Overview
Syllabus
Week 1: Review of Electromagnetic theory: Maxwell’s equations and basics of electric and magnetic fields, Basic Electromagnetic Theory and radiation of electromagnetic waves, E & B Field Measurable quantities and Polarization.Week 2:Radio Astronomy Fundamentals: Discoveries in Radio Astronomy, Brightness, Flux density, Basics of Radiative Transfer, Black Body Radiation, Nyquist Theorem and Noise TemperatureWeek 3:Fundamentals of Antenna Theory: Hertz Dipole, Reciprocity Theorem, Far Field Radiation Pattern, Effective Area, Antenna Temperature, HPBW, Parabolic Reflector Antennas, Aperture Arrays,Week 4:Signal Processing and Receivers: Square Law Detectors, Fourier Transform, Power Spectrum, Linear Systems, Filters, Mixers, Receiver Calibration and Stability, Coherent and incoherent radiometers, Bolometers, Sampling Theorem, Spectrometers, Correlation receivers and Polarimeters.Week 5:Single Dish Observations: Calibration Procedures, Metre to cm wavelength calibration strategies, mm-wavelength calibration strategies, Source Confusion, Spectral Line Confusion, Spectroscopy, multi-pixel feeds – focal plane array.Week 6:Radio Interferometers and Aperture Synthesis: Coherence Function, Two element Interferometers, Correlators, van Cittert-Zernike Equation, Response Interferometers: finite bandwidth, source size and minimum spacing, Time and Bandwidth Smearing, Earth rotation synthesis, Right Ascension and Declination, LST and Hour Angle, Array DesignWeek 7:Interferometric Data Analysis and Calibration: Observing Strategies: Calibrators, Bad Data and Radio Frequency Interference, Gridding uv-data, Amplitude and Phase Calibrations, Bandpass Calibration, Imaging and Self calibration, CLEAN and Maximum Entropy Method. Wideband and Widefield imaging techniques, Non-coplanar Arrays, 2-D vs 3-D imaging.Week 8:Measurement Equation: Wave Polarization, The Poincare Sphere and the Stokes Parameters, Quasi monochromatic Waves, Jones Matrix Formalism, Instrumental Polarization, Calibration for Polarization, The Interferometric Measurement Equation.Week 9:Radio Sky: Emission Mechanisms of Continuous Radiation, Synchrotron Radiation, Thermal and Non-thermal Radio Sources, Radio Galaxies, Pulsars and Time domain radio astronomy, Extra-galactic Sources, Gravitational Lensing, Faraday Rotation. CosmologyWeek 10:Spectral Lines: Spectral line Fundamentals, Dipole Transition Probabilities, The 21cm line of Neutral Hydrogen, The Zeeman Effect, Diffuse Interstellar gas, Galactic neutral hydrogen, Radio Recombination lines, Molecular Line emissionWeek 11:Radio Wave Propagation Effects: i) Neutral Medium, High frequency radio observations and lower atmosphere (Troposphere), Water vapor radiometry, ii) Ionized Medium, Ionosphere, Scattering by Plasma irregularities, Low Frequency radio observations and upper atmosphere, Interplanetary medium, Interstellar Medium,Week 12:Very Long Baseline Interferometry: VLBI System, Fringe fitting, Phase stability and atomic frequency standards, Astrometry and Geodesy
Taught by
Prof. Abhirup Datta
