SDSS-IV MaNGA: A Distinct Mass Distribution Explored in Slow-Rotating
  Early-type Galaxies
  We study the radial acceleration relation (RAR) for early-type galaxies
(ETGs) in the SDSS MaNGA MPL5 dataset. The complete ETG sample show a slightly
offset RAR from the relation reported by McGaugh et al. (2016) at the
low-acceleration end; we find that the deviation is due to the fact that the
slow rotators show a systematically higher acceleration relation than the
McGaugh's RAR, while the fast rotators show a consistent acceleration relation
to McGaugh's RAR. There is a 1\sigma significant difference between the
acceleration relations of the fast and slow rotators, suggesting that the
acceleration relation correlates with the galactic spins, and that the slow
rotators may have a different mass distribution compared with fast rotators and
late-type galaxies. We suspect that the acceleration relation deviation of slow
rotators may be attributed to more galaxy merger events, which would disrupt
the original spins and correlated distributions of baryons and dark matter
orbits in galaxies.
