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arXiv 2602.17039astro-ph.GA
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在压力之下:紫外发射线比值作为活动星系核反馈机制的气压计

Under Pressure: UV Emission Line Ratios as Barometers of AGN Feedback Mechanisms

The University of Michigan(密歇根大学);University of Colorado(科罗拉多大学);Tel Aviv University(特拉维夫大学);The University of Chicago(芝加哥大学);University of Seoul(首尔大学);Northwestern University(西北大学);University of Modena and Reggio Emilia(摩德纳和雷焦艾米利亚大学)
Elise Fuller, Sean D. Johnson, Jonathan Stern, Hsiao-Wen Chen, Ena Choi, Claude-André Faucher-Giguère, Massimo Gaspari, Andy Goulding, Jenny Greene, Timothy M. … 展开作者

Elise Fuller, Sean D. Johnson, Jonathan Stern, Hsiao-Wen Chen, Ena Choi, Claude-André Faucher-Giguère, Massimo Gaspari, Andy Goulding, Jenny Greene, Timothy M. Heckman, Jennifer I-Hsiu Li, Zhuoqi Liu, Nishant Mishra, Kristina Nyland, Kate Rowlands, Gwen C. Rudie, Evan Schneider, Dominika Wylezalek, Nadia L. Zakamska

AI总结:

通过紫外发射线比值研究,发现辐射压力主导AGN喷流动态,部分情况下热风压力也起作用。

摘要:

活动星系核(AGN)的反馈作用被广泛认为调节着大质量星系的增长,尽管其驱动机制仍存在争议。主流理论认为,AGN驱动的喷流要么由直接作用在尘埃星际介质(ISM)上的辐射压力驱动,要么由带入较冷ISM气体的热风驱动,但两种机制的相对贡献仍不确定。通过结合光学发射线测量与高电离紫外发射线,可以确定作用在电离云上的压力源主要是辐射压力还是主要是流体动力学压力,从而约束主导驱动因素。本研究基于宇宙起源光谱仪对五个低红移目标的远紫外(FUV)光谱观测,首次进行了银河尺度AGN驱动喷流的多目标分析。通过比较窄线区紫外发射线比值与变化两种压力源重要性的理论模型,我们发现五分之三的目标落在辐射压力主导的领域。第四目标表现出中间发射线比值,表明辐射压力和热风压力都动态重要。最后,样本中最低亮度的对象可能有动态重要的热风成分,但未检测结果阻止得出明确结论。这些结果表明辐射压力主导环核窄线区云动态,但在某些情况下热风压力也起作用。这与由辐射压力或短暂热风阶段介导的AGN反馈场景一致,该阶段在最初加速喷流后会消散。

英文摘要:

Feedback from active galactic nuclei (AGN) is widely acknowledged to regulate the growth of massive galaxies, though its driving mechanisms are debated. Prevailing theories suggest that AGN-driven outflows are driven either by radiation pressure acting directly on the dusty interstellar medium (ISM) or by hot winds entraining cooler ISM gas, but the relative contribution of each mechanism remains uncertain. By combining optical emission line measurements with highly ionized UV emission lines, it is possible to constrain whether the pressure source applied to ionized clouds is primarily radiation or primarily hydrodynamic, and thus constrain the dominant driver. This study presents the first multi-object analysis of far-ultraviolet (FUV) spectra from galactic-scale AGN-driven outflows in obscured quasars, based on Cosmic Origins Spectrograph observations of five low-redshift targets. By comparing narrow-line region UV emission line ratios to theoretical models that vary the importance of the two pressure sources, we find three out of five targets fall within the radiation pressure-dominated regime. A fourth target exhibits intermediate emission-line ratios that suggest radiation pressure and pressure from a hot wind are both dynamically important. Finally, the lowest-luminosity object in our sample may have a dynamically important hot wind component, but non-detections prevent a clear conclusion in this case. These results suggest radiation pressure dominates circum-nuclear narrow-line region cloud dynamics, but pressure from a hot wind also plays a role in some cases. This is consistent with AGN feedback scenarios mediated by radiation pressure or a short-lived hot wind phase that dissipates after initially accelerating outflows.

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