Introduction to Radio Astronomy
Course number：031M5003H
Period：40
Credit：2.0
Course Property：Professional
Teacher：Han, Jinlin
Course Name：Introduction to Radio Astronomy
Purpose and requirements
This course is a basic lesson for master or doctoral students who are majored in astronomy, astrophysics, astronomical method and instruments or related fields. By learning this course, students should understand what are radio sources in the universe, and how the radio waves are radiated from radio sources as continuum or line emission, how we observe and understand these radiation. Students will study the principles of single dish radio telescopes and synthesis radio telescopes and get to know how they are operated.
Knowledge required
Mathematical physical method, Electromagnetic field theory
Recommended readings:
B.F. Burke & F. Graham-Smith <<An Introduction to Radio Astronomy>> Cambridge University Press, 2012
Content
1. An overview of radio astronomy:
What are the goals of astronomy; What are the main means of astronomical research today; what are the goals of radio astronomy; why do we study celestial objects by using radio wavelengths? what difference between an optical image and a radio image of the a celestial object? How many Nobel Prizes were awarded to radio astronomy for what important discoveries. Where are the big radio telescopes in the world and in China?
2. Radio radiation mechanism of celestial bodies：
Which celestial objects radiate what radio waves? Mechanisms for radio radiation: thermal free-free emission, spectral lines, masers, synchrotron radiation, and pulsar radiation. The main bands or wavelength of radio radiation produced by various celestial objects will be discussed.
3. Single dish radio telescope:
The basic components of a radio telescope and their functions; Why different types of radio telescopes have the various antenna; The basic principle of receivers; the performance of a single dish telescope: beam pattern, resolution and sensitivity; what does the angular resolution and the sensitivity of a radio telescope depends on?
4. Observations of point and extended sources by a single dish telescope:
Definition of point source and extended source. Scanning of the point sources and the beam patterns of the telescope; calibration process; observations of extended sources (the Galactic plane surveys). Polarization of radio signal.
5. Pulsars:
The basic introduction of pulsars, the characteristics of pulsar signal, how to search for unknown pulsar, the observation of individual pulses, the pulse profile. Studies of interstellar medium by pulsar observations, pulse time of arrival (TOA) measurements and its application.
6. Cosmic Microwave Background (CMB):
The Big Bang Model; the discovery of the CMB; the COBE, BOOMERANG, WMAP and PLANCK measurements of the CMB. How many milestones are there in the CMB measurement? What is the key instruments for measuring the CMB? How to use the CMB to study cosmology? What are the next generation instruments for the CMB measurement? What are the important breakthroughs?
7. Synthesis telescopes:
The limits of single dish telescopes, the resolution and sensitivity of radio telescope array, the basic principles of radio telescope array, the introduction of various radio telescope arrays, the UV coverage and interference imaging of space spectrum, and the example of imaging process. The basic principle of the imaging with a radio telescope array; what is a dirty map? How to "clean" the dirty map; what are the similarities and differences between synthesis aperture telescopes and the VLBI. What are the famous radio arrays in the world?
8. Neutral hydrogen HI in galaxies and universe:
How does the HI line emit; the physical and observational characterization of HI; what physical characteristics of clouds can be derived from HI line emission and absorption; How does the HI distribute in the spiral galaxies, especially in the Milky Way; What physics can be learned from the HI observations toward galaxies; how to use HI to study cosmology; HI surveys over the world; the rotation curves of nearby galaxies and dark matter distribution; interaction of galaxies traced by HI; Using Tully-Fisher relation to study the cosmology; HI search for dark galaxies; HI on cosmic scale: 21CMA survey
9. Molecular Clouds:
The scientific significance of molecular clouds; how do molecular clouds form? What is the composition of molecular clouds? How to observe molecular clouds? What are the best observation wavelength for molecular clouds? What spectral lines does the molecular clouds emit? What physical information can be revealed by the observations of molecular lines? How does the molecular clouds of different scales and densities maintain dynamic equilibrium? Why a star can be formed at the core of molecular clouds? What are the observational features of the star forming region? The spectrum and their physics; CO detection of molecular clouds; the magnetic field in the molecular clouds.
10. Star forming regions:
The gas, molecular cloud, and the star forming regions in the Milky way. What are the formation process of small-mass stars? What are the possible ways for massive stars to form? What spectral lines can be observed in the star forming region? The continuum observation of the cloud nucleus and SED; the spectrum diagnosis of the stellar region by spectral lines.
11. Discussions:
Reference
Teaching methods: classroom teaching and discussion
Examination: open book, written and oral test
