The discussion "dark matter vs. modified gravity" has not been resolved yet. It was proposed that dynamical friction could be used to discriminate between the two alternatives. Analytic calculations indicate that, with modified gravity, globular clusters (GCs) of low-mass galaxies experience much stronger dynamical friction than in the equivalent system with Newtonian gravity and dark matter. As a result, in modified gravity the dynamical friction should have already forced the old GCs of low mass galaxies to settle in the centers of the galaxies. This is not observed. I will report on our efforts to verify the analytic results by self-consistent simulations with the MOND gravity. We published already that the core stalling mechanism, that was not considered in the analytic calculations, prevents GC to settle in centers of ultra-diffuse galaxies. In our ongoing work, we investigate GCs of isolated dwarf galaxies. It seems so far that GCs of these galaxies survive if the do not move within the galaxy disk, or if they counterrotate with respect of the galaxy disk. In the simulations done so far, supernova explosions influence the orbits of GCs only at low numerical resolution.
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