Deconstructing Abell 3266: A Major Merger in a Quiet Cluster

We present results of simple N-body simulations that strengthen the suggestion that Abell 3266 is composed of two subunits of comparable mass that have merged recently. Both the real cluster and the N-body dark-matter cluster show mixed signals of substructure under statistical tests. However, in a decidedly nonstatistical approach allowed by the wide-area coverage and the large number of redshifts Quintana, Ramírez, & Way measured in A3266, they sliced the real cluster in redshift space to uncover a peculiar spatial distribution of galaxies that they suggested was the result of a recent merger. In our simulations, a similar distribution is the result of an ongoing merger between two comparable-mass units that started about 2 × 109 yr ago in the N-body simulations. We also find that the distribution of emission-line galaxies in A3266 traces the same structure. We discuss further tests of our merger hypothesis and speculate on the possibility that a similar process might be occurring in other, apparently relaxed clusters at the present epoch.