Annu. Rev. Astron. Astrophys. 1991. 29: 239-274 Copyright © 1991 by Annual Reviews. All rights reserved

3. OBSERVATIONS

Progress in the observational regime has been dramatic. CCD's have dramatically improved the reach of optical telescopes, while HST allows high-resolution photometry of galactic nuclei. The Einstein satellite has opened up the way to X-ray observations of elliptical galaxies (111). Radio maps of HI are becoming readily available (351), and CO detections are increasing steadily (209).

The relevant observations for the delineation of the internal dynamical structure of elliptical galaxies are (maps of) the surface brightness distribution, radial velocity, velocity dispersion, absorption line profiles, and in some cases the velocity field of cold gas. X-ray observations provide quite independent information.