Fulltext

200-µm ISO observations of NGC 6946: evidence for an extended distribution of cold dust

Davies, J. I. ; Alton, P. ; Trewhella, M. ; Evans, R. ; Bianchi, S.

In: Monthly Notices of the Royal Astronomical Society, 1999, vol. 304, no. 3, p. 495-500

Ajouter à la liste personnelle
    Titre
    • 200-µm ISO observations of NGC 6946: evidence for an extended distribution of cold dust
    Auteur
    • Davies, J. I.. Department of Physics and Astronomy, University of Wales, College of Cardiff, PO Box 913, Cardiff CF2 3YB
    • Alton, P.. Department of Physics and Astronomy, University of Wales, College of Cardiff, PO Box 913, Cardiff CF2 3YB
    • Trewhella, M.. IPAC, California Institute of Technology, M.S. 100-22, Pasadena, CA 91125, USA
    • Evans, R.. University of Chicago, Yerkes Observatory, 373 W. Geneva St., PO Box 258, Williams Bay, WI 53191, USA
    • Bianchi, S.. Department of Physics and Astronomy, University of Wales, College of Cardiff, PO Box 913, Cardiff CF2 3YB
    Type de document
    • Postprint
    Langue
    • Anglais
    Publié dans
    • Monthly Notices of the Royal Astronomical Society, 1999, vol. 304, no. 3, p. 495-500. Blackwell Science Ltd
    Autre version électronique
    Identifiant OAI-PMH
    • oai:doc.rero.ch:290331
    Summary
    We have used the Infrared Space Observatory (ISO) to obtain a resolved 200-μm image of the nearby spiral galaxy NGC 6946. We compare these observations with those made at 60 and 100 μm by the Infrared Astronomical Satellite (IRAS). Whereas IRAS mainly detected warm dust (T ≈30 K) heated by star-forming regions, ISO detects an extended distribution of cold dust (T ≤ 22 K) that is heated by the general interstellar radiation field. The IRAS emission tends to follow the molecular gas while it appears that the colder dust has a stronger association with atomic hydrogen. The cold dust is more extended in the radial direction than the optical, near-infrared, IRAS and radio continuum (20 cm) emission. The total gas-to-dust mass ratio is found to be ≈290. This is much closer to the Galactic value of ≈160 than the value of 1240 found using IRAS data only