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arXiv 1306.2488astro-ph.GAastro-ph.COphysics.chem-ph
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用含时化学示踪活动星系核的物理条件

Tracing the Physical Conditions in Active Galactic Nuclei with Time-Dependent Chemistry

Rowin Meijerink, Marco Spaans, Inga Kamp, Giambattista Aresu, Wing-Fai Thi, Peter Woitke

摘要:

我们提出了一个扩展的代码ProDiMo,允许活动星系核和周围的化学是随时间变化的过程建模。我们提出了一个概念验证,并专注于一些天体物理学相关的物种,例如,H+、H2+和H3 +; C+和N +; C和O; CO和H2O; OH+、H2O+和H3O +; HCN和HCO+。我们发现水的冻结被强烈抑制,这影响了活动星系核中氧和碳的化学性质。通常使用的活动星系核示踪剂HCN/HCO+具有强烈的时间依赖性,其比值在超过10^4年的时间内变化超过几个数量级。通过ALMA观测,这个比率可以用来探测窄线区域如何在SMBH吸积率的大波动下演化。在10^4 - 10^8年的时间尺度上,在H3O+、CO和H2O等物种中也发现了强烈的进化趋势。这些分别反映了电离平衡中的时间依赖效应、分子气体产生的瞬态性质以及水的冻结/升华。

英文摘要:

We present an extension of the code ProDiMo that allows for a modeling of processes pertinent to active galactic nuclei and to an ambient chemistry that is time dependent. We present a proof-of-concept and focus on a few astrophysically relevant species, e.g., H+, H2+ and H3+; C+ and N+; C and O; CO and H2O; OH+, H2O+ and H3O+; HCN and HCO+. We find that the freeze-out of water is strongly suppressed and that this affects the bulk of the oxygen and carbon chemistry occurring in AGN. The commonly used AGN tracer HCN/HCO+ is strongly time-dependent, with ratios that vary over orders of magnitude for times longer than 10^4 years. Through ALMA observations this ratio can be used to probe how the narrow-line region evolves under large fluctuations in the SMBH accretion rate. Strong evolutionary trends, on time scales of 10^4-10^8 years, are also found in species such as H3O+, CO, and H2O. These reflect, respectively, time dependent effects in the ionization balance, the transient nature of the production of molecular gas, and the freeze-out/sublimation of water.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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