English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We use the Spitzer SAGE survey of the Magellanic Clouds to evaluate therelationship between the 8-mic PAH emission, 24-mic hot dust emission, and HIIregion radiative transfer. We confirm that in the higher-metallicity LargeMagellanic Cloud, PAH destruction is sensitive to optically thin conditions inthe nebular Lyman continuum: objects identified as optically thin candidatesbased on nebular ionization structure show 6 times lower median 8-mic surfacebrightness (0.18 mJy arcsec^-2) than their optically thick counterparts (1.2mJy arcsec^-2). The 24-mic surface brightness also shows a factor of 3 offsetbetween the two classes of objects (0.13 vs 0.44 mJy arcsec^-2, respectively),which is driven by the association between the very small dust grains andhigher density gas found at higher nebular optical depths. In contrast, PAH anddust formation in the low-metallicity Small Magellanic Cloud is stronglyinhibited such that we find no variation in either 8-mic or 24-mic emissionbetween our optically thick and thin samples. This is attributable to extremelylow PAH and dust production together with high, corrosive UV photon fluxes inthis low-metallicity environment. The dust mass surface densities andgas-to-dust ratios determined from dust maps using Herschel HERITAGE surveydata support this interpretation.

Dust emission at 8-mic and 24-mic as Diagnostics of HII Region Radiative Transfer