Face-on and edge-on projections of young stars (defined as those with an age < 1 Gyr at redshift z = 0) in the four illustrative examples shown in Figure 1 (from left to right, galaxies A, B, C, and D). White labels indicate the mass and rotational support of the young stellar component for each galaxy ($M_{\ast ,\mathrm{young}}$ and κ_rot, young, respectively). Cyan circles show the galaxy size r = r_glx, and orange circles mark r = 1 kpc. All galaxies exhibit a dense young stellar component at r < 1 kpc, with more extended thin discs appearing in the higher mass galaxies. Images were generated with PySPHViewer (Benítez-Llambay 2017).