{
  "id": "1806.05193",
  "version": "v1",
  "published": "2018-06-13T18:00:06.000Z",
  "updated": "2018-06-13T18:00:06.000Z",
  "title": "An ALMA survey of CO in submillimetre galaxies: companions, triggering, and the environment in blended sources",
  "authors": [
    "J. L. Wardlow",
    "J. M. Simpson",
    "Ian Smail",
    "A. M. Swinbank",
    "A. W. Blain",
    "W. N. Brandt",
    "S. C. Chapman",
    "Chian-Chou Chen",
    "E. A. Cooke",
    "H. Dannerbauer",
    "B. Gullberg",
    "J. A. Hodge",
    "R. J. Ivison",
    "K. K. Knudsen",
    "Douglas Scott",
    "A. P. Thomson",
    "A. Weiss",
    "P. P. van der Werf"
  ],
  "comment": "MNRAS in press",
  "categories": [
    "astro-ph.GA"
  ],
  "abstract": "We present ALMA observations of the mid-J 12CO emission from six single-dish selected 870-micron sources in the Extended Chandra Deep Field-South (ECDFS) and UKIDSS Ultra-Deep Survey (UDS) fields. These six single-dish submillimetre sources were selected based on previous ALMA continuum observations, which showed that each comprised a blend of emission from two or more individual submillimetre galaxies (SMGs), separated on 5--10 arcsec scales. The six single-dish submillimetre sources targeted correspond to a total of 14 individual SMGs, of which seven have previously-measured robust optical/near-infrared spectroscopic redshifts, which were used to tune our ALMA observations. We detect CO(3-2) or CO(4-3) at z=2.3--3.7 in seven of the 14 SMGs, and in addition serendipitously detect line emission from three gas-rich companion galaxies, as well as identify four new 3.3-mm selected continuum sources in the six fields. Joint analysis of our CO spectroscopy and existing data suggests that 64 \\pm 18% of the SMGs in blended submillimetre sources are unlikely to be physically associated. However, three of the SMG fields (50%) contain new, serendipitously-detected CO-emitting (but submillimetre-faint) sources at similar redshifts to the 870-micron selected SMGs we targeted. These data suggest that the SMGs inhabit overdense regions, but that these are not sufficiently overdense on ~100 kpc scales to influence the source blending given the short lifetimes of SMGs. We find that 21 \\pm 12% of SMGs have spatially-distinct and kinematically-close companion galaxies (~8--150 kpc and <~300 km/s), which may have enhanced their star-formation via gravitational interactions.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2018-06-13T18:00:06.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "submillimetre galaxies",
      "alma survey",
      "submillimetre sources targeted correspond",
      "robust optical/near-infrared spectroscopic redshifts",
      "blended sources"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}