Dependence of the effective radius on global physical properties. Each column corresponds to a different global physical property: u − r colour, stellar mass, star formation rate, specific star formation rate, and specific dust mass. The entire sample is split into six subpopulations based on each of these properties. Top row: median effective radius for each subpopulation. Middle row: median ratio of the effective radius and the g-band effective radius. Bottom row: scatter plots relating the physical property to the g-band effective radius. All TNG50 galaxies without ongoing star-formation are plotted at SFR = 10⁻³ M_⊙ yr⁻¹ and sSFR = 10⁻¹² yr⁻¹, and all dust-free galaxies at M_dust/M_⋆ = 10⁻⁵. The blue curves represent running medians.