The H I content of dark matter haloes at z ≈ 0 from ALFALFA

Journal article

We combine information from the clustering of H I galaxies in the 100 per cent data release of the Arecibo Legacy Fast ALFA survey, and from the H I content of optically selected galaxy groups found in the Sloan Digital Sky Survey to constrain the relation between halo mass Mh and its average total H I mass content MH I. We model the abundance and clustering of neutral hydrogen through a halo-model-based approach, parametrizing the MH I(Mh) relation as a power law with an exponential mass cut-off. To break the degeneracy between the amplitude and low-mass cut-off of the MH I(Mh) relation, we also include a recent measurement of the cosmic H I abundance from the α.100 sample. We find that all data sets are consistent with a power-law index α = 0.48 ± 0.08 and a cut-off halo mass log10Mmin/(h−1M⊙)=11.18+0.28−0.35⁠. We compare these results with predictions from state-of-the-art magnetohydrodynamical simulations, and find both to be in good qualitative agreement, although the data favours a significantly larger cut-off mass that is consistent with the higher cosmic H I abundance found in simulations. Both data and simulations seem to predict a similar value for the H I bias (⁠bHI=0.878+0.022−0.023⁠) and shot-noise power (⁠PSN=94+20−18[h−1Mpc]3⁠) at redshift z = 0.

Authors: Obuljen, A; Alonso, D; Villaescusa-Navarro, F; Yoon, I; Jones, M

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Oxford University Press
• Journal: Monthly Notices of the Royal Astronomical Society
• Volume: 486
• Issue: 4
• Pages: 5124-5138
• Publication date: 2019-04-24
• Acceptance date: 2019-04-16
• DOI: 10.1093/mnras/stz1118
• EISSN: 1365-2966
• ISSN: 0035-8711
• Language: English
• Keywords: large-scale structure of Universe; cosmology: observations; FFR; galaxies: haloes; methods: data analysis