{
  "id": "1405.5387",
  "version": "v2",
  "published": "2014-05-21T11:53:21.000Z",
  "updated": "2014-07-09T11:35:07.000Z",
  "title": "ALMA Observation of 158 micron [CII] Line and Dust Continuum of a z=7 Normally Star-forming Galaxy in the Epoch of Reionization",
  "authors": [
    "Kazuaki Ota",
    "Fabian Walter",
    "Kouji Ohta",
    "Bunyo Hatsukade",
    "Chris L. Carilli",
    "Elisabete da Cunha",
    "Jorge González-López",
    "Roberto Decarli",
    "Jacqueline A. Hodge",
    "Hiroshi Nagai",
    "Eiichi Egami",
    "Linhua Jiang",
    "Masanori Iye",
    "Nobunari Kashikawa",
    "Dominik A. Riechers",
    "Frank Bertoldi",
    "Pierre Cox",
    "Roberto Neri",
    "Axel Weiss"
  ],
  "comment": "15 pages, 8 figures, 1 table, accepted for publication in The Astrophysical Journal (Updates since last version: text shortened; Figures 7 & 8 updated (a new data point added, IMF unified for SFRs); references updated)",
  "categories": [
    "astro-ph.GA"
  ],
  "abstract": "We present ALMA observations of the [CII] line and far-infrared (FIR) continuum of a normally star-forming galaxy in the reionization epoch, the z=6.96 Ly-alpha emitter (LAE) IOK-1. Probing to sensitivities of sigma_line = 240 micro-Jy/beam (40 km/s channel) and sigma_cont = 21 micro-Jy/beam, we found the galaxy undetected in both [CII] and continuum. Comparison of UV - FIR spectral energy distribution (SED) of IOK-1, including our ALMA limit, with those of several types of local galaxies (including the effects of the cosmic microwave background, CMB, on the FIR continuum) suggests that IOK-1 is similar to local dwarf/irregular galaxies in SED shape rather than highly dusty/obscured galaxies. Moreover, our 3 sigma FIR continuum limit, corrected for CMB effects, implies intrinsic dust mass M_dust < 6.4 x 10^7 M_sun, FIR luminosity L_FIR < 3.7 x 10^{10} L_sun (42.5 - 122.5 micron), total IR luminosity L_IR < 5.7 x 10^{10} L_sun (8 - 1000 micron) and dust-obscured star formation rate (SFR) < 10 M_sun/yr, if we assume that IOK-1 has a dust temperature and emissivity index typical of local dwarf galaxies. This SFR is 2.4 times lower than one estimated from the UV continuum, suggesting that < 29% of the star formation is obscured by dust. Meanwhile, our 3 sigma [CII] flux limit translates into [CII] luminosity, L_[CII] < 3.4 x 10^7 L_sun. Locations of IOK-1 and previously observed LAEs on the L_[CII] vs. SFR and L_[CII]/L_FIR vs. L_FIR diagrams imply that LAEs in the reionization epoch have significantly lower gas and dust enrichment than AGN-powered systems and starbursts at similar/lower redshifts, as well as local star-forming galaxies.",
  "revisions": [
    {
      "version": "v2",
      "updated": "2014-07-09T11:35:07.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "normally star-forming galaxy",
      "alma observation",
      "dust continuum",
      "reionization epoch",
      "star formation"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "doi": "10.1088/0004-637X/792/1/34",
      "journal": "The Astrophysical Journal",
      "year": 2014,
      "month": "Sep",
      "volume": 792,
      "number": 1,
      "pages": 34
    },
    "note": {
      "typesetting": "TeX",
      "pages": 15,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "adsabs": "2014ApJ...792...34O"
    }
  }
}