The r-band azimuthally median surface brightness profiles along the minor axis of all sample galaxies, shown in units of R_e,maj (upper panels) or 〈R_e,maj〉 (lower panels). Galaxies are grouped by stellar mass range in different columns, as indicated in each panel. Here, R_e,maj denotes the half-light radius along the major axis, and 〈R_e,maj​​​​​〉 represents the mass-dependent average R_e,maj predicted by a piecewise log–log linear fit to the R_e,maj–stellar mass relation of our galaxies. Dark-red profiles indicate galaxies with stellar halo detections, while blue profiles indicate galaxies without stellar halo detections. This figure demonstrates that surface brightness profiles normalized by the average major-axis half-light radius exhibit substantially smaller scatter than those normalized by each galaxy’s own half-light radius. See Section 3.3.3 for details.