Syllabus
Introduction to radio astronomy: Definition of radio astronomy as discipline. What kind of information we can acquire - examples from various branches of astronomy. Basic radioastronomical quantities - radio flux, brightness, brightness temperature, polarisation.
Emission mechanisms: Brehmsstrahlung, gyro-synchrotron emission, plasma emission, molecular and atomic transitions at radio wavelengths. Stimulated emission and masers. Further (peculiar) radio emission mechanisms.
Antennas and antenna arrays. Antenna pattern, gain and aperture. Radio detectors from sub-mm up to metric waves. Mixers, principles of heterodyne receiver.
Non-ideal effects in radioastronomical observations: Antenna, detector and atmospheric effects to measurements; (man-made) interference of signal. Calibration of radio data - general introduction. Signal vs. noise. Limits on sensitivity of the device.
Methods of radioastronomy (an overview): Radiometry, polarimetry, single-dish imaging, radio spectroscopy, interferometry. Methods of interferometric observations: Sparse antenna rows and phased arrays, aperture synthesis, VLBI. “Active” radioastronomy - radar observations of meteors and asteroids.
Radio spectroscopy: Principles, methods and examples of utilization. Dynamic spectra of solar radio emissions - diagnostics of fast plasma processes in solar flares. Calibration of spectroscopic data.
Modern radio interferometry - aperture synthesis: Principles and utilization. Calibration of interferometric data. Interferometric synthesis/imaging: dirty and clean radio image, smallest and largest recoverable scale in the image, gridding, weighting, methods of image cleaning.
Combined observation with spectral and spatial resolution - Frequency-Agile Arrays - examples. Calibration and synthesis of multi-frequency interferometric data (multi-frequency synthesis - MFS).
Modern radioastronomical observatories - brief overview of parameters and capabilities: LOFAR, ALMA, MUSER, SKA.
Practical examples I.: How to acquire data from a modern radio observatory - case study for ALMA. Preparing observation proposal: Phase I and II. ALMA Observing Tool - your piece of SW for observing proposal preparation. Estimating the parameters of ALMA data by means of CASA simulation toolkit. How to get support fro your project - a network of ALMA Regional Centers (ARCs ) as an infrastructure connecting the user community and observatory.
Practical examples II: Calibration, imaging and analysis of observed data: Introduction to SW package CASA, case study for ALMA.
Annotation
Radioastronomy (in broader sense) is a bunch of methods of remote diagnostics of astrophysical objects by means of electromagnetic radiation at wavelengths ranging from sub-millimeters to hundreds of meters. It is a relatively young (approx. 80 years) branch of astronomy.
Namely thanks to unprecedented headway in digital technology it experiences revolutionary development in recent years as can be witnessed by newly built (LOFAR, ALMA) and planned (SKA) giant observatories. The lecture aims at introducing the audience into basic principles of methods of radioastronomy and their utilisation.