Halo models of H I selected galaxies
Abstract
Modelling the distribution of neutral hydrogen (H I) in dark matter haloes is important for studying galaxy evolution in the cosmological context. We use a novel approach to infer the H I-dark matter connection at the massive end (m_{H I} >10^{9.8}M_{⊙}) from radio H I emission surveys, using optical properties of low-redshift galaxies as an intermediary. In particular, we use a previously calibrated optical HOD describing the luminosity- and colour-dependent clustering of SDSS galaxies and describe the H I content using a statistical scaling relation between the optical properties and H I mass. This allows us to compute the abundance and clustering properties of H I-selected galaxies and compare with data from the ALFALFA survey. We apply an Markov chain Monte Carlo-based statistical analysis to constrain the free parameters related to the scaling relation. The resulting best-fit scaling relation identifies massive H I galaxies primarily with optically faint blue centrals, consistent with expectations from galaxy formation models. We compare the H I-stellar mass relation predicted by our model with independent observations from matched H I-optical galaxy samples, finding reasonable agreement. As a further application, we make some preliminary forecasts for future observations of H I and optical galaxies in the expected overlap volume of SKA and Euclid/LSST.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- September 2018
- DOI:
- 10.1093/mnras/sty1539
- arXiv:
- arXiv:1712.04469
- Bibcode:
- 2018MNRAS.479.1627P
- Keywords:
-
- methods: analytical;
- methods: numerical;
- (cosmology:) large-scale structure of Universe;
- galaxies: formation;
- Astrophysics - Astrophysics of Galaxies;
- Astrophysics - Cosmology and Nongalactic Astrophysics
- E-Print:
- 12 pages, 11 figures, v2: substantial revision, matches accepted version