Course Outline:
Radio signals, which span nearly five decades of the electromagnetic spectrum, provide a unique diagnostic tool for probing the universe. All astrophysical objects and phenomena either emit or absorb radio waves in a characteristic way. Radio astronomy involves the detection, analysis and interpretation of cosmic radio signals with the aim of studying the physics and chemistry of the objects and phenomena. This course will describe the instruments and techniques used by radio astronomers, and will introduce the various cosmic phenomena that are studied by observing their radio signatures. Extensive use will be made of material from other NASSP courses.
Syllabus:
- Introduction:
Brief history of radio astronomy and an overview of cosmic radio emission. - Radio source mechanisms:
Very brief review of electrodynamics, radiative transfer, thermodynamics, atomic and molecular spectra. Thermal and non-thermal continuum mechanisms, thermal line emission and absorption, non-equilibrium line emission. - Solar system radio sources:
Earth, Moon, Venus, Sun, Jupiter, artificial satellites, radio frequency interference (RFI). - Galactic radio sources:
Supernova remnants (SNR), diffuse non-thermal galactic emission, galactic HI, HII regions, interstellar and circumstellar masers, pulsars, active photospheres and accretion disks. - Extra-galactic radio sources:
Cosmic microwave background radiation (CMBR), normal galaxies, radio galaxies, quasars, era of reionization (EoR). - Radio telescope antennas:
Fourier optics, aperture illumination, beam polar pattern, descriptive parameters. - Radio telescope receivers:
Noise temperature, low noise amplifiers (LNAs), filters, waveguide components, mixers and heterodyne systems. - Radiometry:
Continuum radiometers, pulsar radiometers, polarimeters, spectrometers. - Interferometry and aperture synthesis:
Mutual coherence function, van Cittert-Zernike theorem, two-element interferometers, aperture synthesis. - Practical work
Exploration of and familiarization with typical radio telescope components and systems. Laboratory experiments with receiver systems. Telescope calibration and characterization measurements. Continuum observations of thermal and non-thermal celestial objects. Spectral line observations of an HII region and a dark cloud. Mapping observations of the Sun and the Moon. Timing observations of a radio pulsar.