The Open UniversitySkip to content

A Corona Australis cloud filament seen in NIR scattered light. III. Modelling and comparison with Herschel sub-millimetre data

Juvela, M.; Pelkonen, V.-M.; White, G. J.; Könyves, V.; Kirk, J. and André, P. (2012). A Corona Australis cloud filament seen in NIR scattered light. III. Modelling and comparison with Herschel sub-millimetre data. Astronomy & Astrophysics, 544, article no. A14.

Full text available as:
PDF (Version of Record) - Requires a PDF viewer such as GSview, Xpdf or Adobe Acrobat Reader
Download (2MB)
DOI (Digital Object Identifier) Link:
Google Scholar: Look up in Google Scholar


Context. The dust is an important tracer of dense interstellar clouds but its properties are expected to undergo changes affecting the scattering and emitting properties of the grains. With recent Herschel observations, the northern filament of the Corona Australis cloud has now been mapped in a number of bands from 1.2 μm to 870 μm. The data set provides a good starting point for the study of the cloud over several orders of magnitude in density.

Aims: We wish to examine the differences of the column density distributions derived from dust extinction, scattering, and emission, and to determine to what extent the observations are consistent with the standard dust models.

Methods: From Herschel data, we calculate the column density distribution that is compared to the corresponding data derived in the near-infrared regime from the reddening of the background stars, and from the surface brightness attributed to light scattering. We construct three-dimensional radiative transfer models to describe the emission and the scattering.

Results: The scattered light traces low column densities of AV ~ 1m better than the dust emission, remaining useful to AV ~ 10-15m. Based on the models, the extinction and the level of dust emission are surprisingly consistent with a sub-millimetre dust emissivity typical of diffuse medium. However, the intensity of the scattered light is very low at the centre of the densest clump and this cannot be explained without a very low grain albedo. Both the scattered light and dust emission indicate an anisotropic radiation field. The modelling of the dust emission suggests that the radiation field intensity is at least three times the value of the normal interstellar radiation field.

Conclusions: The inter-comparison between the extinction, light scattering, and dust emission provides very stringent constraints on the cloud structure, the illuminating radiation field, and the grain properties.

Item Type: Journal Item
Copyright Holders: 2012 ESO
ISSN: 1432-0746
Keywords: clouds; infrared; radiative transfer; submillimeter
Academic Unit/School: Faculty of Science, Technology, Engineering and Mathematics (STEM) > Physical Sciences
Faculty of Science, Technology, Engineering and Mathematics (STEM)
Related URLs:
Item ID: 34099
Depositing User: G. J. White
Date Deposited: 26 Jul 2012 08:12
Last Modified: 12 Dec 2018 17:29
Share this page:


Altmetrics from Altmetric

Citations from Dimensions

Download history for this item

These details should be considered as only a guide to the number of downloads performed manually. Algorithmic methods have been applied in an attempt to remove automated downloads from the displayed statistics but no guarantee can be made as to the accuracy of the figures.

Actions (login may be required)

Policies | Disclaimer

© The Open University   contact the OU