冷核心团簇中H α纤维的光谱：运动学、变红和电离源
Optical Spectroscopy of Halpha Filaments in Cool Core Clusters: Kinematics, Reddening, and Sources of Ionization
摘要：
我们获得了9个星系团冷核中H α星云的深、高空间和光谱分辨率的长狭缝光谱。这个样本提供了大量关于电离状态、运动学和星系团冷核中暖气体变红的信息。我们发现在延伸的线状发射灯丝中只有少量的红化，大多数灯丝的E（B-V）< 0.2。[O III]/Hb、[N II]/Ha、[S II]/Ha和[O I]/Ha的组合使我们能够排除由宇宙射线引起的碰撞电离、热传导以及由ICM X射线和活动星系核引起的光电离对核和细丝中的暖气体电离的强贡献。这些数据充分描述了一个复合模型的缓慢冲击和恒星形成。这个模型进一步支持观测到的线宽和低电离线比之间的相关性，这在远紫外观测的基础上具有更温和的恒星形成活动的系统中变得更强。我们发现，更广泛的，狭窄的细丝往往有较浅的速度梯度和较窄的线宽比紧凑的复合物。我们证实，发射线的宽度随半径减小，从FWHM \sim 600 km/s的核的FWHM ~ 100 km/s的最扩展的灯丝。我们认为，这种径向依赖的速度宽度实际上可能与ICM湍流，因此，可以提供一个一瞥到冷核心的湍流量。在几个系统的中心区域（r < 10 kpc），温暖的气体显示出与旋转一致的运动学特征。我们发现，在这个样本中的最延长的灯丝的运动学是大致一致的流入和流出，并建议进一步的研究，连接到无线电和X射线地图的暖气体运动学，以进一步了解所观察到的运动学。
英文摘要：
We have obtained deep, high spatial and spectral resolution, long-slit spectra of the Halpha nebulae in the cool cores of 9 galaxy clusters. This sample provides a wealth of information on the ionization state, kinematics, and reddening of the warm gas in the cool cores of galaxy clusters. We find evidence for only small amounts of reddening in the extended, line-emitting filaments, with the majority of filaments having E(B-V) < 0.2. The combination of [O III]/Hb, [N II]/Ha, [S II]/Ha, and [O I]/Ha allow us to rule out collisional ionization by cosmic rays, thermal conduction, and photoionization by ICM X-rays and AGN as strong contributors to the ionization of the warm gas in both nuclei and filaments. The data are adequately described by a composite model of slow shocks and star formation. This model is further supported by an observed correlation between the linewidths and low ionization line ratios which becomes stronger in systems with more modest star formation activity based on far ultraviolet observations. We find that the more extended, narrow filaments tend to have shallower velocity gradients and narrower linewidths than the compact filamentary complexes. We confirm that the widths of the emission lines decrease with radius, from FWHM \sim 600 km/s in the nuclei to FWHM ~ 100 km/s in the most extended filaments. We suggest that this radial dependence of the velocity width may in fact be linked to ICM turbulence and, thus, may provide a glimpse into the amount of turbulence in cool cores. In the central regions (r < 10 kpc) of several systems the warm gas shows kinematic signatures consistent with rotation. We find that the kinematics of the most extended filaments in this sample are broadly consistent with both infall and outflow, and recommend further studies linking the warm gas kinematics to both radio and X-ray maps in order to further understand the observed kinematics.
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