  This paper is the fourth of a series dealing with the cluster of galaxies
ABCG 85. Using our two extensive photometric and spectroscopic catalogues (with
4232 and 551 galaxies respectively), we discuss here three topics derived from
optical data. First, we present the properties of emission line versus
non-emission line galaxies, showing that their spatial distributions somewhat
differ; emission line galaxies tend to be more concentrated in the south region
where groups appear to be falling onto the main cluster, in agreement with the
hypothesis (presented in our previous paper) that this infall may create a
shock which can heat the X-ray emitting gas and also enhance star formation in
galaxies. Then, we analyze the luminosity function in the R band, which shows
the presence of a dip similar to that observed in other clusters at comparable
absolute magnitudes; this result is interpreted as due to comparable
distributions of spirals, ellipticals and dwarfs in these various clusters.
Finally, we present the dynamical analysis of the cluster using parametric and
non-parametric methods and compare the dynamical mass profiles obtained from
the X-ray and optical data.
