• DOI:10.1093/mnras/stx979
• Corpus ID: 119412926

A halo model for cosmological neutral hydrogen : abundances and clustering

@article{Padmanabhan2016AHM,
  title={A halo model for cosmological neutral hydrogen : abundances and clustering},
  author={Hamsa Padmanabhan and Alexandre R{\'e}fr{\'e}gier and Adam Amara},
  journal={Monthly Notices of the Royal Astronomical Society},
  year={2016},
  volume={469},
  pages={2323-2334}
}

• H. Padmanabhan, A. Réfrégier, A. Amara
• Published 18 November 2016
• Physics
• Monthly Notices of the Royal Astronomical Society

We extend the results of previous analyses towards constraining the abundance and clustering of post-reionization ($z \sim 0-5$) neutral hydrogen (HI) systems using a halo model framework. We work with a comprehensive HI dataset including the small-scale clustering, column density and mass function of HI galaxies at low redshifts, intensity mapping measurements at intermediate redshifts and the UV/optical observations of Damped Lyman Alpha (DLA) systems at higher redshifts. We use a Markov Chain Monte Carlo (MCMC) approach to constrain the parameters of the best-fitting models, both for the HI-halo mass relation and the HI radial density profile. We find that a radial exponential profile results in a good fit to the low-redshift HI observations, including the clustering and the column density distribution. The form of the profile is also found to match the high-redshift DLA observations, when used in combination with a three-parameter HI-halo mass relation and a redshift evolution in the HI concentration. The halo model predictions are in good agreement with the observed HI surface density profiles of low-redshift galaxies, and the general trends in the the impact parameter and covering fraction observations of high-redshift DLAs. We provide convenient tables summarizing the best-fit halo model predictions.