随时间演化的非平衡态光致电离模型及其应用

项目名称： 随时间演化的非平衡态光致电离模型及其应用

项目编号： No.11203080

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 天文学、地球科学

项目作者： 张水乃

作者单位： 中国科学院紫金山天文台

项目金额： 30万元

中文摘要： 光致电离过程存在于宇宙各个角落，并且通常处在非平衡状态随着时间变化。我们将基于最新的原子数据库，建立X射线波段下完备的随时间演化的非平衡态光致电离模型。这个模型更倾向于自然的物理演化过程，而非限定一堆的自由参数。模型将被用于AGN的外流反馈以及熄灭的研究。被AGN电离并吹出的光致电离外流是一种重要的AGN反馈形式，对星系演化有着潜在的重要影响。然而因为AGN外流到黑洞的距离难以测量，它的大小、形态和质量就都无法确定。随时间演化的模型却可以通过观测光谱发生的变化来确定距离，从而了解它的起源、几何形态以及质量能量流出率，最终了解它对黑洞吸积以及星系演化的重要性。AGN 的熄灭使得邻近星系处于较宁静的状态，但有迹象表明某些星系中AGN熄灭的时间并不久远。随时间演化的模型可以通过拟合现在的观测光谱而反推AGN熄灭的时间和物理状态，从而使我们了解生存的星系环境。

中文关键词： 活动星系核；星暴星系；外流；光致电离；电荷交换

英文摘要： Photoionization process is ubiquitous in the universe, normally changing with time in a non-equilibrium state. Based on the latest atomic database, we propose to develop complete time-evolving photoionization models. The models prefer natural physical processes instead of constraining a lot of free parameters, which will be applied to the research of active galactic nuclei (AGN) feedback and quenching. The photoionized outflow ionized and blown out by AGN, is a significant AGN feedback mechanism having potentially influence on galaxy evolution. However, the distance from the outflow to the central black hole is hard to measure, thus the size, shape, mass of outflow are not well understood yet. Based on the time-evolving model, we can obtain the accurate distance of photoionized outflow according to the changes within the observed spectra, then investigate its origin, geometry, and mass- and energy-loss rate, and finally find out how important the outflow is for black hole accretion and galaxy evolution. The quenching of AGN makes our neighbor galaxies quieter. However, there are indications that some AGN quenched not long ago. AGN quenching time and physical state can be derived by fitting the observed spectrum with the time-evolving model, that help us better understand our living galactic surroundings.

英文关键词： AGN；starburst；outflow；photoionization；charge exchange