{
  "id": "2007.14484",
  "version": "v1",
  "published": "2020-07-28T21:05:44.000Z",
  "updated": "2020-07-28T21:05:44.000Z",
  "title": "Validation of Emission-Line Galaxies Target Selection Algorithms for the Dark Energy Spectroscopic Instrument Using the MMT Binospec",
  "authors": [
    "Tanveer Karim",
    "Jae H. Lee",
    "Daniel J. Eisenstein",
    "Etienne Burtin",
    "John Moustakas",
    "Anand Raichoor",
    "Christophe Yèche"
  ],
  "comment": "16 pages, 9 figures, Accepted by the MNRAS on 2020 July 27",
  "categories": [
    "astro-ph.GA",
    "astro-ph.CO"
  ],
  "abstract": "The forthcoming Dark Energy Spectroscopic Instrument (DESI) experiment plans to measure the effects of dark energy on the expansion of the Universe and create a $3$D map of the Universe using galaxies up to $z \\sim 1.6$ and QSOs up to $z \\sim 3.5$. In order to create this map, DESI will obtain spectroscopic redshifts of over $30$ million objects; among them, a majority are \\oii emitting star-forming galaxies known as emission-line galaxies (ELGs). These ELG targets will be pre-selected by drawing a selection region on the $g - r$ vs. $r - z$ colour-colour plot, where high redshift ELGs form a separate locus from the lower redshift ELGs and interlopers. In this paper, we study the efficiency of three ELG target selection algorithms -- the final design report (FDR) cut based on the DEEP2 photometry, Number Density Modelling and Random Forest -- to determine how the combination of these three algorithms can be best used to yield a simple selection boundary that will be best suited to meet DESI's science goals. To do this, we selected $17$ small patches in the DESI footprint where we run the three target selection algorithms to pre-select ELGs based on their photometry. We observed the pre-selected ELGs using the MMT Binospec, which is similar in functionality to the DESI instrument, to obtain their spectroscopic redshifts and fluxes of $1054$ ELGs. By analysing the redshift and fluxing distribution of these galaxies, we find that although NDM performed the best, simple changes in the FDR definition would also yield sufficient performance.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2020-07-28T21:05:44.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "dark energy spectroscopic instrument",
      "emission-line galaxies target selection algorithms",
      "mmt binospec"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 16,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}