The apparent anticorrelation between the mass opacity of interstellar dust and the surface density of interstellar gas

Whitworth, A. P. ORCID: https://orcid.org/0000-0002-1178-5486 and Priestley, F. D. 2020. The apparent anticorrelation between the mass opacity of interstellar dust and the surface density of interstellar gas. Monthly Notices of the Royal Astronomical Society - Letters 494 (1) , L48-L52. 10.1093/mnrasl/slaa034

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Abstract

Recent analyses of Herschel observations suggest that in nearby disc galaxies the dust mass opacity at 500μm⁠, κ500, decreases with increasing gas surface density, ΣISM. This apparent anticorrelation between κ500 and ΣISM is opposite to the behaviour expected from theoretical dust evolution models; in such models, dust in denser, cooler regions (i.e. regions of increased ΣISM) tends to grow and therefore to have increased κ500. We show, using a toy model, that the presence of a range of dust temperatures along the line of sight can lead to spuriously low estimated values of κ500. If in regions of higher ΣISM the range of dust temperatures extends to lower values (as seems likely), the magnitude of this effect may be sufficient to explain the apparent anticorrelation between κ500 and ΣISM. Therefore there may not be any need for spatial variation in the intrinsic dust properties that run counter to theoretical expectations.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Advanced Research Computing @ Cardiff (ARCCA) Physics and Astronomy
Publisher:	Blackwell Publishing Ltd
ISSN:	1745-3925
Date of First Compliant Deposit:	4 May 2020
Date of Acceptance:	14 February 2020
Last Modified:	21 Jun 2024 14:12
URI:	https://orca.cardiff.ac.uk/id/eprint/131149

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