Page 1 - 83 basic knowledge of astronomy

Tetsuo Sasao and Andr´e B. Fletcher
Introduction to VLBI Systems
Chapter 1
Lecture Notes for KVN Students
Based on Ajou University Lecture Notes
(to be further edited)
Version 2.
Issued on February 28, 2005.
Revised on March 18, 2005.
Revised on February 4, 2006.

Basic Knowledge of
Radio Astronomy

Contents

1 ‘Windows’ for Ground–based Astronomy 3

2 Various Classifications of Astronomical Radio Sources 4

3 Spectra of Typical Continuum Radio Sources 4

4 Spectralline Radio Sources 5

5 Designations of Astronomical Radio Sources 8

6 Designations of Frequency Bands 8

7 Basic Quantities in Radio Astronomy 9
7.1 Intensity (Specific/Monochromatic Intensity) I ν or Brightness
B ν . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
7.2 Constancy of the Monochromatic Intensity I ν . . . . . . . . . 10
7.3 ‘Spectral Flux Density’ or ‘Flux Density’ or ‘Flux’ S ν . . . . . 11
7.4 Power/Energy/Radiation Flux Density S . . . . . . . . . . . . 12
. . . . . . . 12
7.5 Spectral Energy Density per Unit Solid Angle u ν
7.6 Spectral Energy Density U ν . . . . . . . . . . . . . . . . . . . 13

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