Volume 541, May 2012
|Number of page(s)||4|
|Published online||26 April 2012|
Herschel/SPIRE observations of the dusty disk of NGC 4244⋆
1 European Space Agency Research Fellow (ESTEC), Keplerlaan 1, 2200 AG Noordwijk, The Netherlands
2 INAF – Arcetri Astrophysical Observatory, Largo Enrico Fermi 5, 50125 Florence, Italy
3 Department of Astronomy, University of Washington, Box 351580, Seattle, WA 98195, USA
4 Leibniz Institut für Astrophysik Potsdam (AIP), An der Sternwarte 16, 14482 Potsdam, Germany
5 Sterrenkundig Observatorium, Universiteit Gent, Krijgslaan 281-S9, 9000 Gent, Belgium
6 Kapteyn Astronomical Institute, University of Groningen, PO Box 800, 9700 AV Groningen, The Netherlands
7 Institute of Astronomy and Astrophysics, National Observatory of Athens, P. Penteli, 15236 Athens, Greece
8 Space Telescope Science Institute, 3700 San Martin Drive, MD 21218, Baltimore, USA
Received: 9 December 2011
Accepted: 19 March 2012
We present Herschel/SPIRE images at 250, 350, and 500 μm of NGC 4244, a typical low-mass, disk-only and edge-on spiral galaxy. The dust disk is clumpy and shows signs of truncation at the break radius of the stellar disk. This disk coincides with the densest part of the Hi disk. We compare the spectral energy distribution (SED), including the new SPIRE fluxes, to 3D radiative transfer models; a smooth model disk and a clumpy model with embedded heating. Each model requires a very high value for the dust scale-length (hd = 2−5 h∗), higher dust masses than previous models of NGC 4244 (Md = 0.47−1.39 × 107 M⊙) and a face-on optical depth of τVf.o. = 0.4-1.12, in agreement with previous disk opacity studies. The vertical scales of stars and dust are similar. The clumpy model much better mimics the general morphology in the sub-mm images and the general SED. The inferred gas-to-dust mass ratio is compatible with those of similar low-mass disks. The relatively large radial scale-length of the dust disk points to radial mixing of the dusty ISM within the stellar disk. The large vertical dust scale and the clumpy dust distribution of our SED model are both consistent with a scenario in which the vertical structure of the ISM is dictated by the balance of turbulence and self-gravity.
Key words: radiative transfer / dust, extinction / ISM: structure / galaxies: ISM / galaxies: spiral / galaxies: structure
© ESO, 2012
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.