Conclusions

Our initial survey of 600 square degrees of the Centaurus A group of galaxies in 21-cm has yielded 10 new candidate members, bringing the number of known members within this initial HIPASS survey region to 31, and the total number group members to 38. The new members add 50% to the number of members known, but only 4% to the total luminosity of the group. The new members all have optical counterparts, and most are very faint, late-type, gas rich low surface brightness dwarfs. Due to our survey technique, and that of the previous survey by Côté et al. (1997), very little is known about the possible early-type (dE/dSph) population of the Cen A group. However, the luminosity distribution of the Cen A galaxies is entirely consistent with the Local Group luminosity distribution to the optical limit of galaxies detected within the Cen A group. While 30% of the Local Group galaxies with M

are early-type systems, <15% of the known Cen A galaxies are. If there is a Local Group type population of early-type galaxies, then the luminosity distributions of the two groups may be significantly different.

© Copyright Astronomical Society of Australia 1997