{
  "id": "1709.06102",
  "version": "v1",
  "published": "2017-09-18T18:01:02.000Z",
  "updated": "2017-09-18T18:01:02.000Z",
  "title": "Dust attenuation in 2<z<3 star-forming galaxies from deep ALMA observations of the Hubble Ultra Deep Field",
  "authors": [
    "R. J. McLure",
    "J. S. Dunlop",
    "F. Cullen",
    "N. Bourne",
    "P. N. Best",
    "S. Khochfar",
    "R. A. A. Bowler",
    "A. D. Biggs",
    "J. E. Geach",
    "D. Scott",
    "M. J. Michalowski",
    "W. Rujopakarn",
    "E. van Kampen",
    "A. Kirkpatrick",
    "A. Pope"
  ],
  "comment": "17 pages, 7 figures, submitted to MNRAS",
  "categories": [
    "astro-ph.GA"
  ],
  "abstract": "We present the results of a new study of the relationship between infrared excess (IRX), UV spectral slope (beta) and stellar mass at redshifts 2<z<3, based on a deep Atacama Large Millimeter Array (ALMA) 1.3-mm continuum mosaic of the Hubble Ultra Deep Field (HUDF). Excluding the most heavily-obscured sources, we use a stacking analysis to show that z~2.5 star-forming galaxies in the mass range 9.25 <= log(M/Msun) <= 10.75 are fully consistent with the IRX-beta relation expected for a relatively grey attenuation curve, similar to the commonly adopted Calzetti law. Based on a large, mass complete, sample of 2 <= z <= 3 star-forming galaxies drawn from multiple surveys, we proceed to derive a new empirical relationship between beta and stellar mass, making it possible to predict UV attenuation (A_1600) and IRX as a function of stellar mass, for any assumed attenuation law. Once again, we find that z~2.5 star-forming galaxies follow A_1600-mass and IRX-mass relations consistent with a relatively grey attenuation law, and find no compelling evidence that star-forming galaxies at this epoch follow a reddening law as steep as the Small Magellanic Cloud (SMC) extinction curve. In fact, we use a simple simulation to demonstrate that previous determinations of the IRX-beta relation may have been biased toward low values of IRX at red values of beta, mimicking the signature expected for an SMC-like dust law. We show that this provides a plausible mechanism for reconciling apparently contradictory results in the literature and that, based on typical measurement uncertainties, stellar mass provides a cleaner prediction of UV attenuation than beta. Although the situation at lower stellar masses remains uncertain, we conclude that for 2<z<3 star-forming galaxies with log(M/Msun) >= 9.75, both the IRX-beta and IRX-mass relations are well described by a Calzetti-like attenuation law.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2017-09-18T18:01:02.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "hubble ultra deep field",
      "deep alma observations",
      "dust attenuation",
      "star-forming galaxies",
      "uv spectral slope"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 17,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}