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Modelling the evolution of PAH abundance in galaxies

Authors :
Shiau-Jie Rau
Hiroyuki Hirashita
M. S. Murga
Source :
Monthly Notices of the Royal Astronomical Society. 489:5218-5224
Publication Year :
2019
Publisher :
Oxford University Press (OUP), 2019.

Abstract

We investigate the evolution of polycyclic aromatic hydrocarbon (PAH) abundance in a galaxy, which is a crucial step to understand the evolution of bright emission features in the mid-infrared range. We calculate the evolution of dust grain size distribution in a manner consistent with the physical conditions of the interstellar medium by post-processing our previous hydrodynamical simulation of an isolated disc galaxy. We also differentiate between aromatic and non-aromatic grains for carbonaceous dust species and explicitly considered the aromatization process. As a consequence, our model explains the metallicity dependence of PAH abundances in nearby galaxies well. The PAH abundance increase is driven particularly by the interplay between shattering and accretion (dust growth). The fast aromatization guarantees that the small carbonaceous grains trace PAHs very well. Since shattering and accretion are sensitive to the dust abundance, we predict that the PAH-to-dust abundance ratio increases as the metallicity increases. This is consistent with the observation data of nearby galaxies.<br />Comment: Accepted by Monthly Notices of the Royal Astronomical Society (2019/9/5) 7 pages 4 figures

Details

ISSN :
13652966 and 00358711
Volume :
489
Database :
OpenAIRE
Journal :
Monthly Notices of the Royal Astronomical Society
Accession number :
edsair.doi.dedup.....9068f5c2b8254b383dc7aabd9f35138b
Full Text :
https://doi.org/10.1093/mnras/stz2532