{
  "id": "1608.05080",
  "version": "v1",
  "published": "2016-08-17T20:00:04.000Z",
  "updated": "2016-08-17T20:00:04.000Z",
  "title": "A resolved map of the infrared excess in a Lyman Break Galaxy at z=3",
  "authors": [
    "M. P. Koprowski",
    "K. E. K. Coppin",
    "J. E. Geach",
    "N. K. Hine",
    "M. Bremer",
    "S. C. Chapman",
    "L. J. M. Davies",
    "T. Hayashino",
    "K. K. Knudsen",
    "M. Kubo",
    "B. D. Lehmer",
    "Y. Matsuda",
    "D. J. B. Smith",
    "P. P. van der Werf",
    "G. Violino",
    "T. Yamada"
  ],
  "comment": "Accepted in The Astrophysical Journal Letters",
  "categories": [
    "astro-ph.GA",
    "astro-ph.CO"
  ],
  "abstract": "We have observed the dust continuum of ten z=3.1 Lyman Break Galaxies with the Atacama Large Millimeter/Submillimeter Array at ~450 mas resolution in Band 7. We detect and resolve the 870um emission in one of the targets with an integrated flux density of S(870)=(192+/-57) uJy, and measure a stacked 3-sigma signal of S(870)=(67+/-23) uJy for the remaining nine. The total infrared luminosities estimated from full spectral energy distribution fits are L(8-1000um)=(8.4+/-2.3)x10^10 Lsun for the detection and L(8-1000um)=(2.9+/-0.9)x10^10 Lsun for the stack. With HST ACS I-band imaging we map the rest-frame UV emission on the same scale as the dust, effectively resolving the 'infrared excess' (IRX=L_FIR/L_UV) in a normal galaxy at z=3. Integrated over the galaxy we measure IRX=0.56+/-0.15, and the galaxy-averaged UV slope is beta=-1.25+/-0.03. This puts the galaxy a factor of ~10 below the IRX-beta relation for local starburst nuclei of Meurer et al. (1999). However, IRX varies by more than a factor of 3 across the galaxy, and we conclude that the complex relative morphology of the dust relative to UV emission is largely responsible for the scatter in the IRX-beta relation at high-z. A naive application of a Meurer-like dust correction based on the UV slope would dramatically over-estimate the total star formation rate, and our results support growing evidence that when integrated over the galaxy, the typical conditions in high-z star-forming galaxies are not analogous to those in the local starburst nuclei used to establish the Meurer relation.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2016-08-17T20:00:04.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "lyman break galaxy",
      "infrared excess",
      "resolved map",
      "local starburst nuclei",
      "full spectral energy distribution fits"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}