论文标题
芳族尘埃物种和银河进化中的灭绝曲线的自洽建模
Self-consistent modelling of aromatic dust species and extinction curves in galaxy evolution
论文作者
论文摘要
我们制定并计算星系中尘埃的演变，重点是各种粉尘成分之间的区别 - 硅酸盐，芳香碳和非芳香族碳。我们将星系视为一个单区对象，并采用了我们先前工作中开发的晶粒尺寸分布的演化模型。我们进一步包括芳香化和淀粉化（芳香化的反反应）。我们将3--50Å半径范围内的小芳香晶粒视为多环芳烃（PAHS）。我们还以一致的方式计算灭绝曲线，并与硅酸盐和芳香族和非芳族碳质粉尘进行丰富。我们的模型很好地解释了PAH丰度是附近星系中金属性的函数。就碳碰撞强度和远处脱离的斜率而言，灭绝曲线与年龄$ \ sim $ 10 GYR时的银河系曲线相似。 We also apply our model to starburst galaxies by shortening the star formation time-scale (0.5 Gyr) and increasing the dense-gas fraction (0.9), finding that the extinction curve maintains bumpless shapes (because of low aromatic fractions), which are similar to the extinction curves observed in the Small Magellanic Cloud and high-redshift quasars.因此，我们的模型成功地解释了低红移和高红移的灭绝曲线形状的多样性。
We formulate and calculate the evolution of dust in a galaxy focusing on the distinction among various dust components -- silicate, aromatic carbon, and non-aromatic carbon. We treat the galaxy as a one-zone object and adopt the evolution model of grain size distribution developed in our previous work. We further include aromatization and aliphatization (inverse reaction of aromatization). We regard small aromatic grains in a radius range of 3--50 Å as polycyclic aromatic hydrocarbons (PAHs). We also calculate extinction curves in a consistent manner with the abundances of silicate and aromatic and non-aromatic carbonaceous dust. Our model nicely explains the PAH abundance as a function of metallicity in nearby galaxies. The extinction curve become similar to the Milky Way curve at age $\sim$ 10 Gyr, in terms of the carbon bump strength and the far-ultraviolet slope. We also apply our model to starburst galaxies by shortening the star formation time-scale (0.5 Gyr) and increasing the dense-gas fraction (0.9), finding that the extinction curve maintains bumpless shapes (because of low aromatic fractions), which are similar to the extinction curves observed in the Small Magellanic Cloud and high-redshift quasars. Thus, our model successfully explains the variety in extinction curve shapes at low and high redshifts.
