Different higher order kinematics between star-forming and quiescent galaxies based on the SAMI, MAGPI, and LEGA-C surveys

We present the first statistical study of spatially integrated non-Gaussian stellar kinematics spanning 7 Gyr in cosmic time. We use deep, rest-frame optical spectroscopy of massive galaxies (stellar mass M * > 10 Me-10.5 ) at redshifts z = 0.05, 0.3, and 0.8 from the SAMI, MAGPI, and LEGA-C surveys, to measure the excess kurtosis h( 4) of the stellar velocity distribution, the latter parametrized as a Gauss-Hermite series. We find that at all redshifts where we have large enough samples, h(4) anticorrelates with the ratio between rotation and dispersion, highlighting the physical connection between these two kinematic observables. In addition, and independently from the anticorrelation with rotation-to-dispersion ratio, we also find a correlation between h(4) and M *, potentially connected to the assembly history of galaxies. In contrast, after controlling for mass, we find no evidence of independent correlation between h 4 and aperture velocity dispersion or galaxy size. These results hold for both star-forming and quiescent galaxies. For quiescent galaxies, h(4) also correlates with projected shape, even after controlling for the rotation to-dispersion ratio. At any given redshift, star-forming galaxies have lower h(4) compared to quiescent galaxies, highlighting the link between kinematic structure and star-forming activity.