Optical properties of the NGC 5328 group of galaxies

We present the results of a photometric and spectroscopic study of seven members of the NGC 5328 group of galaxies, a chain of galaxies spanning over 200 kpc (H-0= 70 km s(-1) Mpc(-1)). We analyse the galaxy structure and study the emission-line properties of the group members looking for signatures of star formation and active galactic nucleus activity. We finally attempt to infer, from the modelling of line-strength indices, the stellar population ages of the early-type members. We investigate also the presence of a dwarf galaxy population associated with the bright members. The group is composed of a large fraction of early-type galaxies including NGC 5328 and 5330, two 'bona fide' ellipticals at the centre of the group. In both galaxies no recent star formation episodes are detected by the H beta versus MgFe line-strength indices of these galaxies. 2MASX J13524838-2829584 has extremely boxy isophotes which are believed to be connected to a merging event: line-strength indices suggest that this object probably had a recent star formation episode. A warped disc component emerges from the model subtracted image of 2MASX J13530016-2827061, which is interpreted as a signature of an ongoing interaction with the rest of the group. Ongoing star formation and nuclear activity are present in the projected outskirts of the group. The two early-type galaxies 2MASX J13523852-2830444 and 2MASX J13525393-2831421 show spectral signatures of star formation, while a Seyfert 2 type nuclear activity is detected in MCG-5-33-29.