Top panel: The HIMF estimated using galaxies of the ALFALFA survey is shown in blue, in the FATHOMER catalog with a redshift threshold of 0.05 is shown in red, and in the FATHOMER catalog without a redshift threshold is shown in black, respectively. The bottom panel shows the corresponding HI mass histogram of the galaxies in the FATHOMER catalog with redshift threshold, without redshift threshold, and the ALFALFA catalog.