A WEAK GRAVITATIONAL LENSING ANALYSIS OF ABELL-2390

We report on the detection of dark matter in the cluster AbeU. 2390 us ing the weak gravitational distortion of background galaxies. We find that the cluster light and total mass distributions are quite similar over an angular scale of similar or equal to 7' (1 h(-1) Mpc). The clu ster galaxy and mass distributions are centered on the cluster cD gala xy and exhibit elliptical isocontours in the central similar or equal to 2' (280 h(-1) kpc). The major axis of the ellipticity is aligned wi th the direction defined by the cluster cD and a ''straight arc'' loca ted similar or equal to 38'' to the northwest. We determined the radia l mass-to-light profile for this cluster and found a constant value of (320 +/- 90) h M(circle dot)/L(circle dot V), which is consistent wit h other published determinations. We also compared our weak lensing, a zimuthally averaged radial mass profile with a spherical mass model de termined by a virial analysis of the cluster. We find good agreement b etween the two profiles, although there are weak indications that the mass model determined from the virial analysis may be falling off more steeply for theta greater than or equal to 3' (420 h(-1) kpc).