Rest equivalent width (W₀) of the absorption lines as a function of the foreground galaxy’s stellar mass (log[M_⋆/M_⊙]), SFR (log[M_⊙ yr⁻¹]), effective radius (r_eff), and azimuthal angle (ϕ). The W₀ measurements come from composite spectra considering galaxy pairs at all projected distances (b < 23″) and split by the corresponding galaxy property. Stellar mass and SFR W₀ were obtained from composite spectra considering 238 bg galaxies, while r_eff and ϕ come from composite spectra considering 97 bg galaxies (see Sect. 2 and Table 2). Average and median W₀ are shown in solid red and open blue symbols; solid black symbols correspond to upper limits with S/N < 3. The error bars correspond to 1σ confidence intervals for average or median values based on a bootstrap analysis. The panels include the results from the Kendall-Tau correlation test: the correlation coefficients r_τ and their corresponding p-value (the probability of no correlation). The panels of absorption lines with detections in only two subsamples also show the results from a Student’s t-test: the difference between a pair of mean values given by the t coefficient and their corresponding p-value (the probability of significant difference amongst means).