SDSS-IV MaNGA: A Distinct Mass Distribution Explored in Slow-Rotating Early-type Galaxies

TL;DR

This study investigates the radial acceleration relation in early-type galaxies from SDSS MaNGA, revealing differences between slow and fast rotators that suggest varied mass distributions and evolutionary histories.

Contribution

It demonstrates that slow rotators deviate from the established RAR, indicating a link between galaxy spin and mass distribution, which was not previously well understood.

Findings

Slow rotators show higher acceleration relations than McGaugh's RAR.

Fast rotators are consistent with McGaugh's RAR.

Deviation in slow rotators may be due to galaxy mergers.

Abstract

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.