•M87 is a cD galaxy,
technically. Kormendy (1982)
distinguishes these from being merely giant ellipticals.
–Extensive stellar
envelope up to 100 kpc
–Only in regions of
enhanced galaxy density (a factor of 100 denser than
the average)
–Multiple nuclei in
25-50% of cDs (a very rare thing)
•
•Regular cD clusters are
systems that have relaxed into dynamical
equilibrium.
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