{
  "id": "1901.07458",
  "version": "v1",
  "published": "2019-01-22T16:49:03.000Z",
  "updated": "2019-01-22T16:49:03.000Z",
  "title": "Modelling the spinning dust emission from LDN 1780",
  "authors": [
    "Matias Vidal",
    "Clive Dickinson",
    "S. E. Harper",
    "Simon Casassus",
    "A. N. Witt"
  ],
  "comment": "14 pages, 11 figures, submitted to MNRAS",
  "categories": [
    "astro-ph.GA"
  ],
  "abstract": "We study the anomalous microwave emission (AME) in the Lynds Dark Nebula (LDN) 1780 on two angular scales. Using available ancillary data at an angular resolution of 1 degree, we construct an SED between 0.408 GHz to 2997 GHz. We show that there is a significant amount of AME at these angular scales and the excess is compatible with a physical spinning dust model. We find that LDN 1780 is one of the clearest examples of AME on 1 degree scales. We detected AME with a significance > 20$\\sigma$. We also find at these angular scales that the location of the peak of the emission at frequencies between 23-70 GHz differs from the one on the 90-3000 GHz map. In order to investigate the origin of the AME in this cloud, we use data obtained with the Combined Array for Research in Millimeter-wave Astronomy (CARMA) that provides 2 arcmin resolution at 30 GHz. We study the connection between the radio and IR emissions using morphological correlations. The best correlation is found to be with MIPS 70$\\mu$m, which traces warm dust (T$\\sim$50K). Finally, we study the difference in radio emissivity between two locations within the cloud. We measured a factor $\\approx 6$ of difference in 30 GHz emissivity. We show that this variation can be explained, using the spinning dust model, by a variation on the dust grain size distribution across the cloud, particularly changing the carbon fraction and hence the amount of PAHs.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2019-01-22T16:49:03.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "spinning dust emission",
      "angular scales",
      "spinning dust model",
      "lynds dark nebula",
      "dust grain size distribution"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 14,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}