Velocities in Abell 3266

The arm could be produced by a recent merger with another cluster, that moved from the front and SW direction and scattered from the main cluster core into the arm. This model allows us to derive an epoch for the collision between the more massive core and the front edge of the incoming cluster of 4x10^9^h_50_^-1^yr ago and of ~2x10^9^h_50_^-1^yr for the merging of both cores. Formation of the dumb-bell is a later merger process of the two BCMs, consistent with theoretical estimates.

The collision picture is also consistent with the distorted X-ray image. The very northernmost parts of the arm could, alternatively, be interpreted as ongoing infall of a few outlying loose groups. The suggestion of a faint galaxy system within 400h_50_^-1^kpc, satellite to the central dumb-bell, is maintained in spite of the large central velocity dispersion value; however, confirmation requires data for further compact faint members.

From several mass estimators we derived a cluster dynamical mass value of 5x10^15^h_50_^-1^M_{sun}_, but this value should be seen in the merger context described.