Fig. 2: Comparison between the relations of μ_HI to M_⋆ and μ_HI to M_BH for the galaxy sample.

a,b, μ_HI–M_⋆ (a) and μ_HI–M_BH (b) correlations. Galaxies are divided into early- and late-type galaxies based on their Sérsic indexes (separated at n = 2), which are shown in red and blue contours, respectively. The HI-detection rates of galaxies are shown as a function of stellar masses and BH masses. The vertical dashed lines indicate the position when the HI-detection fraction reaches 60%. c,d, μ_HI–M_⋆ (c) and μ_HI–M_BH (d) relations. The best-fitted relations for the HI-detected galaxy sample and the BH sample are shown by the black and orange lines, respectively. We also show the μ_HI–M_BH relation for the full galaxy sample with the magenta line in d. e,f, The partial correlation between μ_HI and M_⋆ while controlling for M_BH (e), and the partial correlation between μ_HI and M_BH while controlling for M_⋆ (f). The corresponding Spearman coefficients are shown in each panel. The median 1σ error bars for the galaxy sample are shown in c and d.