Astronomy & Astrophysics

**Table 5:** Classification of the compact groups and neighbouring large scale structures. The radius in Mpc is the median radius of each group, while the value given in parenthesis is the physical radius in Mpc corresponding to 15 $\hbox {$^\prime $ }$ . Column 4 shows the logarithm of the galaxy number density for the original galaxies in the SCGs, while in Col. 5 we show the logarithm of the galaxy number density obtained by including all galaxies within a circle of 15 $\hbox {$^\prime $ }$ radius. It is worth to note the remarkable galaxy density of SCG0018-4854.
Group name	Class	R	Galaxy number density	Galaxy number density (all galaxies)	Notes
		(Mpc)	(gal $\times$ Mpc^-3)	(gal $\times$ Mpc^-3)
SCG2159-3210	B	0.0436 (0.081)	4.06	3.60	core+halo system
SCG2353-6101	A	0.0841	3.08	--
SCG0018-4854	A	0.0232	4.88	--
SCG0122-3819	B	0.0708 (0.126)	3.43	2.77	close to Abell 2911^a
SCG0141-3429	A	0.1438	2.60	--	HIPASS J0133-34
SCG0227-4312	A	0.2417	2.00	--

^a Katgert (1996) identifies multiple redshift systems in this cluster, which at z = 0.08080.