Observational signatures of the dust size evolution in isolated galaxy simulations
arxiv(2024)
摘要
We aim to provide observational signatures of the dust size evolution in the
ISM, in particular exploring indicators of polycyclic aromatic hydrocarbon
(PAH) mass fraction (q_PAH) defined as the mass fraction of PAHs relative
to total dust grains. Additionally, we validate our dust evolution model by
comparing the observational signatures from our simulations to those from
observations. We model the evolution of grain size distribution of Milky
Way-like and NGC 628-like galaxies representing star-forming galaxies with a
hydrodynamic simulation code, GADGET4-OSAKA, which considers dust production
and interstellar processing. Furthermore, we perform post-processing dust
radiative transfer with SKIRT based on the simulations to predict the
observational properties. We find that the intensity ratio between 8 um and 24
um correlates with q_PAH and can be used as an indicator of PAH mass
fraction. However, this ratio is influenced by the radiation field. As another
indicator, we suggest the 8 um-to-total infrared intensity ratio (ν I_ν(8
μ m)/I(TIR)), which tightly correlates with q_PAH. Furthermore, we
explore the spatial evolution of q_PAH in the simulated Milky Way-like
galaxy using ν I_ν(8 μ m)/I(TIR). We find that the spatially resolved
q_PAH increases with metallicity at lower metallicity (Z<0.2 Zsun) due to
the interplay between accretion and shattering while it decreases with
metallicity at higher metallicity (Z>0.2 Zsun) due to coagulation. Finally, we
compare the above indicators in the NGC 628-like simulation with those observed
in NGC 628. Consequently, our simulation underestimates the PAH mass fraction
throughout the entire galaxy. This is probably because PAH is too efficiently
lost by coagulation in the interstellar medium in our model, which suggests
that the inhibition of coagulation of the PAHs is key to enhancing PAH
formation.
更多查看译文
AI 理解论文
溯源树
样例
生成溯源树,研究论文发展脉络
Chat Paper
正在生成论文摘要