2018/05/02 by Andrej Obuljen, David Alonso, Francisco Villaescusa-Navarro +2 · 1 citation
Physics and Astronomy · #astro-ph.CO
paper · pdf · doi:10.1093/mnras/stz1118
17 pages, 11 figures. Comments welcome
arxiv created 2018/05/02 · arxiv updated 2019/05/01
We combine information from the clustering of HI galaxies in the 100% data release of the Arecibo Legacy Fast ALFA survey (ALFALFA), and from the HI content of optically-selected galaxy groups found in the Sloan Digital Sky Survey (SDSS) to constrain the relation between halo mass Mh and its average total HI mass content M\rm HI. We model the abundance and clustering of neutral hydrogen through a halo-model-based approach, parametrizing the M\rm HI(Mh) relation as a power law with an exponential mass cutoff. To break the degeneracy between the amplitude and low-mass cutoff of the M\rm HI(Mh) relation, we also include a recent measurement of the cosmic HI abundance from the α.100 sample. We find that all datasets are consistent with a power-law index α=0.44± 0.08 and a cutoff halo mass log10M\rm min/(h-1M_\odot)=11.27+0.24-0.30. We compare these results with predictions from state-of-the-art magneto-hydrodynamical simulations, and find both to be in good qualitative agreement, although the data favours a significantly larger cutoff mass that is consistent with the higher cosmic HI abundance found in simulations. Both data and simulations seem to predict a similar value for the HI bias (b\rm HI=0.875±0.022) and shot-noise power (P\rm SN=92+20-18 [h-1\rm Mpc]3) at redshift z=0.