cD Galaxies
	• 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) – Mutiple nuclei in 25-50% of cDs (a very rare thing) • Regular cD clusters are systems that have relaxed into dynamical equilibirum.