Magnetic field strength as a function of stellar mass, M_★ (solid green circles). The solid green line shows the best fit, and the shaded region indicates the 95% prediction interval, with the fitted slopes and the standard error reported in the legend. Samples of observed galaxies taken from the literature and their best-fit relations (dashed lines) are overlaid with different colour crosses: red (Lacki & Beck 2013), black (Lopez-Rodriguez 2023), purple (Chyży et al. 2011), navy blue (Beck et al. 2019), and goldenrod (Stein et al. 2019; Mora-Partiarroyo et al. 2019; Stein et al. 2020; Heald et al. 2022, CHANGES survey). Their respective best-fit relations are shown as dashed lines. Upper limits from Chyży et al. (2011) are shown as downward arrows, and are excluded from the fits.