Establishing HI mass vs. stellar mass and halo mass scaling relations using an abundance matching method

We combined data from the Sloan Digital Sky Survey (SDSS) and the Arecibo Legacy Fast ALFA Survey (ALFALFA) to establish the HI mass vs. stellar mass and halo mass scaling relations using an abundance matching method that is free of the Malmquist bias. To enable abundance matching, a cross-match between the SDSS DR7 galaxy group sample and the ALFALFA HI sources provides a catalog of 16520 HI-galaxy pairs within 14270 galaxy groups (halos). By applying the observational completeness reductions for both optical and HI observations, we used the remaining 8180 ALFALFA matched sources to construct the model constraints. Taking into account the dependence of HI mass on both the galaxy and group properties, we establish two sets of scaling relations: one with a combination of stellar mass, (g-r) color and halo mass, and the other with stellar mass, specific star-formation rate (sSFR), and halo mass. We demonstrate that our models can reproduce the HI mass component as both stellar mass and halo mass. Additional tests showed that the conditional HI mass distributions as a function of the cosmic web type and the satellite fractions were well recovered.