Multitemperature mapping of dust structures throughout the Galactic Plane using the PPMAP tool with Herschel Hi-GAL data
Date Issued
2017
Author(s)
Marsh, K. A.
•
Whitworth, A. P.
•
Lomax, O.
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Ragan, S. E.
•
•
Cambrésy, L.
•
•
Eden, D.
•
•
Kacsuk, P.
•
•
Palmeirim, P.
•
•
Schneider, N.
•
•
Description
We thank Thomas Haworth for an illuminating discussion, and Matt Griffin for helpful comments on the manuscript. We also thank the referee for helpful comments. We have
made use of data from the Spitzer Space Telescope, operated by the Jet Propulsion Laboratory, California Institute of Technology, under contract with NASA. This research has been supported by the EU-funded ViaLactea Network (Ref. FP7-SPACE-607380).
Abstract
We describe new Hi-GAL based maps of the entire Galactic Plane, obtained using continuum data in the wavelength range 70-500 μm. These maps are derived with the PPMAP procedure, and therefore represent a significant improvement over those obtained with standard analysis techniques. Specifically they have greatly improved resolution (12 arcsec) and, in addition to more accurate integrated column densities and mean dust temperatures, they give temperature-differential column densities, I.e., separate column density maps in twelve distinct dust temperature intervals, along with the corresponding uncertainty maps. The complete set of maps is available online. We briefly describe PPMAP and present some illustrative examples of the results. These include (a) multi-temperature maps of the Galactic H II region W5-E, (b) the temperature decomposition of molecular cloud column-density probability distribution functions, and (c) the global variation of mean dust temperature as a function of Galactocentric distance. Amongst our findings are: (I) a strong localised temperature gradient in W5-E in a direction orthogonal to that towards the ionising star, suggesting an alternative heating source and providing possible guidance for models of the formation of the bubble complex, and (II) the overall radial profile of dust temperature in the Galaxy shows a monotonic decrease, broadly consistent both with models of the interstellar radiation field and with previous estimates at lower resolution. However, we also find a central temperature plateau within ∼6 kpc of the Galactic centre, outside of which is a pronounced steepening of the radial profile. This behaviour may reflect the greater proportion of molecular (as opposed to atomic) gas in the central region of the Galaxy.
Volume
471
Issue
3
Start page
2730
Issn Identifier
0035-8711
Ads BibCode
2017MNRAS.471.2730M
Rights
open.access
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