Details

Autor(en) / Beteiligte

• Khramtsova, M. S
• Wiebe, D. S
• Boley, P. A
• Pavlyuchenkov, Ya. N

Titel

Polycyclic aromatic hydrocarbons in spatially resolved extragalactic star-forming complexes

Ist Teil von

• Monthly notices of the Royal Astronomical Society, 2013-05, Vol.431 (2), p.2006-2016

Ort / Verlag

London: Oxford University Press

Erscheinungsjahr

2013

Link zum Volltext

Quelle

Free E-Journal (出版社公開部分のみ）

Beschreibungen/Notizen

• The abundance of polycyclic aromatic hydrocarbons (PAHs) in low- and high-metallicity galaxies has been widely discussed since the time when detailed infrared data for extragalactic objects were first obtained. On the scales of entire galaxies, a smaller PAH abundance in lower metallicity galaxies is often observed. We study this relationship for star-forming regions in nearby galaxies, for a sample containing more than 200 H ii complexes, using spatially resolved observations from the Herschel Space Observatory and Spitzer Space Telescope. We use a model for the dust emission to estimate the physical parameters (PAH abundance, metallicity, ultraviolet radiation field, etc.) of these complexes. The same correlation of PAH abundance with metallicity, as seen for entire galaxies, is apparently preserved at smaller scales, at least when the Kobulnicky and Kewley metallicity calibration is used. We discuss possible reasons for this correlation, noting that traces of less effective PAH formation in low-metallicity asymptotic giant branch stars should be smeared out by radial mixing in galactic discs. Effective destruction by the harder and more intensive ultraviolet field in low-metallicity environments is qualitatively consistent with our data, as the ultraviolet field intensity, derived from the infrared photometry, is indeed smaller in H ii complexes with lower metallicity.