Evidence for dumbbell shaped Dark Matter concentrations ( multiple Galaxy Anchor Black Holes) lining up before merging. See also: Hot gas concentration between nearest approaching Dark Matter concentrations. (Q-FFF Theory) see: See: Sparse reconstruction etc. Austin Peel et al. (Uni. Paris Saclay)
and: https://www.researchgate.net/publication/338750176_The_Origin_of_Ultra_Diffuse_Galaxies_UDGs_2_2017