Velocity gradient and galaxy properties correlation

Here, we look for additional trends at fixed {sigma}_e_ using 1339 galaxies (M_*_>~6x10^9^M_{sun}_) with different morphologies in the MaNGA (DR14) sample with integral-field spectroscopy data. We focus on the gradients ({gamma}_rms_={sigma}(R_e_/4)/{sigma}_e_) of the stellar root-mean-square velocity (V_rms_=sqrt(V^2^+{sigma}^2^)), which we show traces the total mass density gradient {gamma}_tot_ derived from dynamical models and, more weakly, the bulge fraction.

We confirm that {gamma}_rms_ increases with {sigma}_e_, age, and metallicity. We additionally find that these correlations still exist at fixed {sigma}_e_, where galaxies with larger {gamma}_rms_ are found to be older and more metal-rich. It means that mass density gradients contain information of the stellar population which is not fully accounted for by {sigma}_e_.