MOND and the dynamics of NGC1052-DF2
  The dwarf galaxy NGC1052-DF2 has recently been identified as potentially
lacking dark matter. If correct, this could be a challenge for MOND, which
predicts that low surface brightness galaxies should evince large mass
discrepancies. However, the correct prediction of MOND depends on both the
internal field of the dwarf and the external field caused by its proximity to
the giant elliptical NGC1052. Taking both into consideration under plausible
assumptions, we find $\sigma_{\rm MOND} =
13.4^{+4.8}_{-3.7}\;\mathrm{km}\,\mathrm{s}^{-1}$. This is only marginally
higher than the claimed 90\% upper limit on the velocity dispersion ($\sigma <
10.5\;\mathrm{km}\,\mathrm{s}^{-1}$), and compares well with the observed root
mean square velocity dispersion ($\sigma =
14.3\;\mathrm{km}\,\mathrm{s}^{-1}$). We also discuss a few caveats on both the
observational and theoretical side. On the theory side, the internal
virialization time in this dwarf may be longer that the time scale of variation
of the external field. On the observational side, the paucity of data and their
large uncertainties call for further analysis of the velocity dispersion of
NGC1052-DF2, to check whether it poses a challenge to MOND or is a success
thereof.
