Fornax Cluster H IMF. In the main figure, the circles represent the observed number density (ϕ) from the binned data (for display purposes) with their respective Poisson uncertainties. The filled circles represent galaxies in the M_HI range used to fit the H IMF, log(M_HI/M_⊙) ≥ 7, while the open circles represent galaxies in the M_HI range excluded from the fit due to their obvious departure from a power law. The black line is the MML fit and the grey-shaded region denotes the 1σ uncertainty of the fit. A volume of 2.7 Mpc³ was assumed for the fitting procedure. The dashed orange line indicates the H IMF of the local Universe (Ma et al. 2025), and the dotted orange line indicates the local Universe H IMF, scaled by using the Fornax ϕ_*. Top panel: Histogram of the H I-detected galaxies.