{
  "id": "1711.05130",
  "version": "v1",
  "published": "2017-11-14T14:52:21.000Z",
  "updated": "2017-11-14T14:52:21.000Z",
  "title": "On the faint-end of the galaxy luminosity function in the Epoch of Reionization: updated constraints from the HST Frontier Fields",
  "authors": [
    "B. Yue",
    "M. Castellano",
    "A. Ferrara",
    "A. Fontana",
    "E. Merlin",
    "R. Amorín",
    "A. Grazian",
    "E. Mármol-Queralto",
    "M. J. Michałowski",
    "A. Mortlock",
    "D. Paris",
    "S. Parsa",
    "S. Pilo",
    "P. Santini",
    "M. Di Criscienzo"
  ],
  "comment": "9 pages, 5 figures, 2 tables, submitted to ApJ",
  "categories": [
    "astro-ph.GA",
    "astro-ph.CO"
  ],
  "abstract": "Ultra-faint galaxies are hosted by small dark matter halos with shallow gravitational potential wells, hence their star formation activity is more sensitive to feedback effects. The shape of the faint-end of the high-$z$ galaxy luminosity function (LF) contains important information on star formation and its interaction with the reionization process during the Epoch of Reionization (EoR). High-$z$ galaxies with $M_{\\rm UV}\\gtrsim-17$ have only recently become accessible thanks to the Frontier Fields (FFs) survey combining deep HST imaging and the gravitational lensing effect. In this paper we investigate the faint-end of the LF at redshift $>$5 using the data of FFs clusters Abell 2744 (A2744), MACSJ0416.1-2403 (M0416), MACSJ0717.5+3745 (M0717) and MACSJ1149.5+2223 (M1149). We analyze both an empirical and a physically-motivated LF model to obtain constraints on a possible turn-over of LF at faint magnitudes. In the empirical model the LF drops fast when the absolute UV magnitude $M_{\\rm UV}$ is much larger than a turn-over absolute UV magnitude $M_{\\rm UV}^{\\rm T}$. We obtain $M_{\\rm UV}^{\\rm T}\\gtrsim-14.3$ at 2$\\sigma$ confidence level (C.L.) for $z\\sim6$. In the physically-motivated analytical model, star formation in halos with circular velocity below $v_c^*$ is fully quenched if these halos are located in ionized regions. Using updated lensing models and new additional FFs data, we re-analyze previous constraints on $v_c^*$ and $f_{\\rm esc}$ presented by Castellano et al. 2016a (C16a) using a smaller dataset. We obtain new constraints on $v_c^*\\lesssim 57$ km s$^{-1}$ and $f_{\\rm esc}\\lesssim 63\\%$ (both at 2$\\sigma$ C.L.) and conclude that there is no turn-over detected so far from the analyzed FFs data. Forthcoming JWST observations will be key to tight these constraints further.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2017-11-14T14:52:21.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "galaxy luminosity function",
      "hst frontier fields",
      "updated constraints",
      "reionization",
      "star formation"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 9,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}