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We present Southern African Large Telescope (SALT) follow-up observations ofseven massive clusters detected by the Atacama Cosmology Telescope (ACT) on thecelestial equator using the Sunyaev-Zel'dovich (SZ) effect. We conductedmulti-object spectroscopic observations with the Robert Stobie Spectrograph inorder to measure galaxy redshifts in each cluster field, determine the clusterline-of-sight velocity dispersions, and infer the cluster dynamical masses. Wefind that the clusters, which span the redshift range 0.3 < z < 0.55, range inmass from (5 -- 20) x 10$^{14}$ solar masses (M200c). Their masses, given theirSZ signals, are similar to those of southern hemisphere ACT clusters previouslyobserved using Gemini and the VLT. We note that the brightest cluster galaxy inone of the systems studied, ACT-CL J0320.4+0032 at z = 0.38, hosts a Type IIquasar. Only a handful of such systems are currently known, and thereforeACT-CL J0320.4+0032 may be a rare example of a very massive halo in whichquasar-mode feedback is actively taking place.

SALT spectroscopic observations of galaxy clusters detected by ACT and a Type II quasar hosted by a brightest cluster galaxy