银盘径向丰度梯度及冷气体的演化

发布时间：2018-03-28 09:31

本文选题：星系　切入点：演化　出处：《天文学报》2014年02期

【摘要】：为了理解银盘的径向丰度梯度形成机制及冷气体演化,构建了银盘化学演化模型.模型中采用了与分子氢相关的恒星形成律,分开计算了分子氢和原子氢的质量面密度演化,并将模型预言和观测到的各物理量径向轮廓进行了比较.结果表明,模型预言对所采用的内落时标非常敏感,采用与分子氢相关的恒星形成律的模型能够较好地符合银盘基本的观测特征,尤其是能够自然地得到银盘的径向氧丰度梯度和冷气体的径向面密度轮廓.采用瞬时或非瞬时循环假设对冷气体的演化影响不大,在气体密度较低的情况下更是如此.
[Abstract]:In order to understand the radial abundance gradient formation mechanism of silver disk and the cold gas evolution, a silver disk chemical evolution model was constructed. The star formation law related to molecular hydrogen was used in the model, and the mass surface density evolution of molecular hydrogen and atomic hydrogen were calculated separately. The model predictions are compared with the observed radial profiles of physical quantities. The results show that the model predictions are very sensitive to the falling time scales used. The model of star formation law related to molecular hydrogen can better accord with the basic observation characteristics of silver disk. Especially, the radial oxygen abundance gradient of silver disk and the radial surface density profile of cold gas can be obtained naturally. The instantaneous or non-instantaneous cycle assumption has little effect on the evolution of cold gas, especially when the gas density is low.
【作者单位】：中国科学院上海天文台;中国科学院大学;
【基金】：国家自然科学基金项目(Y345321001)资助
【分类号】：P156

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