{
  "id": "1806.10612",
  "version": "v1",
  "published": "2018-06-27T18:00:03.000Z",
  "updated": "2018-06-27T18:00:03.000Z",
  "title": "HOD modelling of high redshift galaxies using the BLUETIDES simulation",
  "authors": [
    "Aklant Kumar Bhowmick",
    "Duncan Campbell",
    "Tiziana DiMatteo",
    "Yu Feng"
  ],
  "comment": "14",
  "categories": [
    "astro-ph.GA",
    "astro-ph.CO"
  ],
  "abstract": "We construct halo occupation distribution (HOD) models of high redshift ($z \\gtrsim 7.5$) galaxies with $M_{*}>10^8~M_{\\odot}/h$ using the BlueTides hydrodynamic simulation suite, with a particular emphasis on modelling the small scale / 1-halo clustering ($0.01\\lesssim r \\lesssim 1~ h^{-1}\\rm{Mpc}$). Similar to low redshift studies, we find that the central and satellite mean HODs ($\\left<N_{\\mathrm{cen}}\\right>$ and $\\left<N_{\\mathrm{sat}}\\right>$) can be modeled by a smoothed step function and a power law respectively. The number density of satellite galaxies is however significantly suppressed compared to low redshift (satellite fractions drop from $\\sim 50 \\%$ at $z=0$ to $\\lesssim 10 \\%$ at $z=7.5$). The mean number of satellites, $\\left<N_{\\mathrm{sat}}\\right> < 1$ for halo masses below $3 \\times 10^{11} M_{\\odot}/h$ (a rare halo at these redshifts). For the radial number density profiles, satellites with $10^8 \\lesssim M^* \\lesssim 10^{9} M_{\\odot}/h$ in halos with $M_H \\gtrsim 3 \\times10^{11} M_{\\odot}/h$ are consistent with NFW (with concentrations $c_{\\mathrm{sat}} \\sim 10-40$). Within halos of mass $M_H\\lesssim 3 \\times 10^{11} M_{\\odot}/h$ satellites exhibit a power law profile with slope -3. Because these halos dominate the small scale clustering, the resulting 1-halo term is steeper than predicted using standard NFW profiles. Using this power-law profile for satellites, we can successfully reproduce the small-scale clustering exhibited by BlueTides galaxies using HOD modelling. We predict the highest probability of detecting satellites at $z>7.5$ is around centrals of $M^*\\sim 3 \\times 10^{10} M_{\\odot}/h$ (with $M^{*}\\gtrsim$ a few $10^{7} M_{\\odot}/h$ ). This should be achievable with the James Webb Space Telescope (JWST).",
  "revisions": [
    {
      "version": "v1",
      "updated": "2018-06-27T18:00:03.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "high redshift galaxies",
      "hod modelling",
      "bluetides simulation",
      "low redshift",
      "radial number density profiles"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}