MaNGA and ATLAS3D ETGs kinematic data

We identify 2342 early-type galaxies (ETGs) from the TNG100 simulation and 236 ETGs from the TNG50 simulation to compare with those from MaNGA and ATLAS^3D^ surveys. For these systems, we measure key kinematic parameters widely employed in both observational and simulation-based studies, including the intrinsic spin parameter {lambda}_R,intr_ (it indicates that the {lambda}_R_ parameter is measured when the galaxy is viewed edge-on), the cylindrical rotational energy fraction {kappa}_rot_, and structural mass ratios such as the spheroid mass fraction f_spheroid_ and the stellar halo mass fraction f_halo_.

This study performs a comparative kinematic analysis of early-type galaxies using IllustrisTNG simulations and IFS data from MaNGA and ATLAS^3D^ . We demonstrate that standard classifiers --- the {lambda}_R_(Re)=0.31 SQRT(epsilon) relation and k_5_{bar} coefficient (the higher-order term of the Fourier decomposition of velocity fields) --- fail to align with kinematic bimodality. Revised thresholds are proposed: the spin {lambda}_R,intr_~0.4, the ratio of rotation energy {kappa}_rot_~0.5, and the mass fraction of a spheroid component f_spheroid_~0.6.