THE ROTATION CURVE OF THE CLUSTER GALAXY DC-1842-62 NO-24 DOES NOT DECREASE

Whitmore, Forbes & Rubin (1988) claimed a good correlation between slo pe of rotation curves and location within a cluster, in the sense that inner galaxies tend to have falling rotation curves, while outer and field galaxies tend to have flat or rising rotation curves. Amram et a l (1993, 1995b) did not confirm these correlations. Nevertheless, the lack of very inner galaxies in our sample did not allow us to conclude if environmental effects are important within a very small distance f rom the cluster center. The galaxy DC 1842-62 #24 presented both the m ost decreasing rotation curve and the closest location to the cluster center in Whitmore et al.'s sample (1988), and thus was a crucial case in the study of rotation curve behaviour in the very inner part of a cluster. From Perot-Fabry observations, we definitively find a non-dec reasing rotation curve for this galaxy. A two-component mass model (di sk plus halo) rules out any decrease of the rotation curve and indicat es that luminous matter is dominant.