Cumulative overdensity factor δ_cumul obtained in Sect. 5.1 vs. distance from the luminosity–comoving area relation for quasars’ Lyα nebulae, in units of its rms. For the luminosity–area relation we use the reference inliers fit in Arrigoni Battaia et al. (2023). Each data point has a circle that is logarithmically scaled following the comoving area of the Lyα nebulae. Magenta dots indicate systems with radio-loud sources. The dotted line with shaded area indicates the relation and one rms = 0.17 dex.