Modified Newtonian dynamics mass-to-light ratios for galaxy groups

I estimate modified Newtonian dynamics (MOND) M/L-values for nine galaxy groups that were recently studied by Tully et al. Instead of the large M/L-values that they find with Newtonian dynamics (up to 1200 solar units), the MOND estimates fall around 1 solar unit. Tully et al. find a systematic and significant difference between the M/L-values of groups that do not contain luminous galaxies and those that do: Dwarfs-only groups have larger M/L-values (by a factor of 5). The MOND M/L-values do not show this trend; the Newtonian disparity is traced back to the dwarfs-only groups having systematically smaller intrinsic accelerations (similar sizes but rather smaller velocity dispersions).