Spectroscopy with Single Dish Radio Telescopes

Abstract

This chapter is in three parts. The first presents the fundamental equations of level populations and radiative transfer which govern spectral line emission and absorption. Lines in the cm-wave band have similarities which allow us to simplify the equations. The further simplification of a two level system (a good approximation for H I gives the familiar formulae for the 21-cm line. The second part of the lesson deals with mapping, and the combination of single dish and interferometer data. We consider the effect of gridding single dish data using a convolving function. Mapping speeds and techniques are discussed. The third part discusses the spectral line cube and its moments. The use of the first moments to determine the dynamical structure of a disk is discussed.