arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1809.07804astro-ph.GAastro-ph.HE
收藏

活动星系核驱动外流主题的变化：光度演化和环境密度分布

Variations on a theme of AGN-driven outflows: luminosity evolution and ambient density distribution

W. Ishibashi, A. C. Fabian

备注：
accepted for publication in MNRAS
阅读 PDF
arXiv 页面 ↗HTML 原文 ↗

摘要：

星系外流现在通常在星暴和活动星系核（AGN）的宿主星系中观察到。然而，对于它们的物理驱动机制还没有明确的共识。我们以前已经表明，活动星系核辐射反馈，驱动的辐射压力尘埃，可以解释所观察到的星系外流的动力学和能量，辐射捕获考虑在内。在这里，我们概括了我们的模型结果，明确考虑的时间演化的中心活动星系核光度，壳质量演化在不同的环境密度分布。在固定质量壳层的情况下，动量比（$ζ= \dot{p}/(L/c)$）和能量比（$ε_k = \dot{E}_{k}/L$）的高观测值可能归因于辐射捕获或活动星系核光度衰减。相反，对于从周围环境中席卷质量的膨胀壳层，AGN光度的衰减不能解释所观察到的高能量，辐射捕获是必要的。事实上，强辐射捕获，例如由于高尘埃与气体的比例，可以大大提高外流能量。我们得到一个不同的径向依赖的流出能量（$ζ(r)$，$ε_k(r)$）的辐射捕获和光度衰减的情况下，这可能有助于区分这两种情况。在这个框架内，最近发现的“化石”流出，具有惊人的高价值的能量，可以解释为过去活动星系核活动的遗迹。因此，所观察到的外流属性可以提供有用的约束活动星系核活动的过去历史和/或流出发射区的物理条件。

英文摘要：

Galactic outflows are now commonly observed in starburst and active galactic nuclei (AGN) host galaxies. Yet, there is no clear consensus on their physical driving mechanism(s). We have previously shown that AGN radiative feedback, driven by radiation pressure on dust, can account for the observed dynamics and energetics of galactic outflows, provided that radiation trapping is taken into account. Here we generalise our model results by explicitly considering the temporal evolution of the central AGN luminosity, and the shell mass evolution in different ambient density distributions. In the case of fixed-mass shells, the high observed values of the momentum ratio ($ζ= \dot{p}/(L/c)$) and energy ratio ($ε_k = \dot{E}_{k}/L$) may be attributed to either radiation trapping or AGN luminosity decay. In contrast, for expanding shells sweeping up mass from the surrounding environment, a decay in AGN luminosity cannot account for the observed high energetics, and radiation trapping is necessarily required. Indeed, strong radiation trapping, e.g. due to high dust-to-gas ratios, can considerably boost the outflow energetics. We obtain a distinct radial dependence for the outflow energetics ($ζ(r)$, $ε_k(r)$) in the case of radiation trapping and luminosity decay, which may help discriminate between the two scenarios. In this framework, the recently discovered `fossil' outflows, with anomalously high values of the energetics, may be interpreted as relics of past AGN activity. The observed outflow properties may therefore provide useful constraints on the past history of AGN activity and/or the physical conditions of the outflow launch region.

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。

↑