The Environments of Astronomical Masers

Abstract

This chapter provides an overview of the various astronomical environments where maser action takes place, serving as an introduction to the more detailed descriptions of various maser sources in the following chapters. The discussion here is necessarily brief, and concentrates on concepts and processes with the most relevance to maser operation. This astronomical background material can be supplemented by the following references: the book Physical Processes in the Interstellar Medium by Spitzer (1978); the proceedings Physical Processes in Red Giants (Iben and Renzini 1981), Masers, Molecules and Mass Outflows in Star Forming Regions (Haschick 1986), Interstellar Processes (Hollenbach and Thronson 1987) and Molecular Astrophysics (Hartquist 1990); and reviews by Cohen (1989), Herman and Habing (1985a), Iben and Renzini (1983), Litvak (1974), Mathis (1990), McKee and Hollenbach (1980), Moran (1990), Reid and Moran (1981, 1988), Shu, Adams and Lizano (1987), and Yorke (1986).