Stellar angular momentum for MaNGA galaxies

Thanks to the size of the sample and the large number of massive galaxies, we unambiguously detect a clear bimodality in the ({lambda}_Re_, {epsilon}) diagram which may result from fundamental differences in galaxy assembly history. There is a sharp secondary density peak inside the region of the diagram with low {lambda}_Re_ and {epsilon}<0.4, previously suggested as the definition for slow rotators. Most of these galaxies are visually classified as non-regular rotators and have high velocity dispersion.

The intrinsic bimodality must be stronger, as it tends to be smoothed by noise and inclination. The large sample of slow rotators allows us for the first time to unveil a secondary peak at +/-90{deg} in their distribution of the misalignments between the photometric and kinematic position angles. We confirm that genuine slow rotators start appearing above M>=2x10^11^M_{sun}_ where a significant number of high-mass fast rotators also exist.