The sum of the virial masses of A2933N and A2933S as a function of the projection angle α. The horizontal lines show the mass estimate (full line) and errors (dashed lines) (see Sect. 4.5.1). The projected distance of 0.75 Mpc and radial velocity difference at rest of 550 km s^-1 are derived from the two BCG’s location and velocities. The two systems were at zero separation 12.2 Gyr ago. The dotted line represents the Newtonian criterion for gravitational binding. Two bound incoming (BIa and BIb) and one bound outgoing (BO) are found compatible with our mass estimates.