2001/07/30 by William D. Watson, Watson, William D.
Physics and Astronomy · #Astrophysics (astro-ph) #FOS: Physical sciences #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/0107572
to appear in the proceedings of IAU Symposium #206: Cosmic Masers (Mangaratiba, Brazil; March 2001); 16 pages; 5 figures; uses newpasp.sty
arxiv created 2001/07/30 · arxiv updated 2009/12/01
Theoretical research on extragalactic masers (and hence this review) is almost entirely directed toward 22 GHz water masers in circumnuclear disks with the focus being the near ideal masing disk at the nucleus of the galaxy NGC4258. The discussion here is organized around (1) the excitation and conditions for the masers, (2) the spatial and spectral appearance of the maser emission, and (3) the mass accretion rate and structure of the disk. In addition, a summary is given of the basic physics (spectral linebeadths and maser polarization) that underlies certain interpretations of these and other astrophysical masers.