AI 中文总结
本研究利用XMM-Newton与Chandra观测数据，重新研究MACS J1931.8-2634星系团的铁丰度分布，发现二维铁分布不对称，排除尘埃耗散情景，为AGN反馈的金属印记提供新观测约束。
AI 中文摘要
星系团内介质（ICM）中的金属空间分布是追踪星系团化学与动力学演化历史的灵敏示踪体。多数冷却核（CC）星系团呈现中心峰状的铁丰度轮廓，但若干异常体显示出反常的中心铁下降，可能与活动星系核（AGN）活动相关。我们利用新的XMM-Newton观测数据，重新研究大质量冷却核星系团MACS J1931.8-2634中已报道的大尺度（约100千秒差距）中心铁下降，目的是验证这一特征并搜寻AGN反馈对ICM金属丰度分布的印记。我们分析了约170千秒的新XMM-Newton观测数据，并重分析了约100千秒的存档Chandra观测数据，从CCD光谱推导了径向及二维（2D）铁丰度图，利用高分辨率RGS光谱限制氖/铁丰度比以检验尘埃耗散情景，在SPEX中采用更新的原子数据库以及单温度和多温度碰撞电离平衡模型进行光谱拟合。XMM-Newton径向轮廓未证实之前报道的中心铁下降，但二维铁分布明显不对称：富铁区域沿AGN空腔轴拉长，延伸至其直接尺度之外；核区的氖/铁比与太阳值一致（${\rm Ne/Fe}=1.03^{+0.25}_{-0.23}$），反对尘埃耗散情景。
英文摘要
The spatial distribution of metals in the intracluster medium (ICM) is a sensitive tracer of the chemical and dynamical history of galaxy clusters. While most cool-core (CC) clusters exhibit a centrally peaked Fe abundance profile, several outliers show an anomalous central Fe drop, potentially associated with the AGN activities. We revisit the reported large-scale (sim 100 kpc) central Fe drop in the massive CC cluster MACS J1931.8-2634 using new XMM-Newton observations. We aim to verify this feature and search for imprints of AGN feedback on the ICM metallicity distribution. We analyzed sim 170 ks of new XMM-Newton observations and re-analyzed sim 100 ks archived Chandra observations. We derived radial and two-dimensional (2D) Fe abundance maps from CCD spectra. High-resolution RGS spectra were used to constrain the Ne/Fe abundance ratio to test the dust depletion scenario. Spectral fitting was performed in SPEX using an updated atomic database and both single- and multi-temperature collisional ionization equilibrium models. The previously reported central Fe drop is not confirmed in the radial profile from XMM-Newton. However, the 2D Fe distribution is clearly asymmetric: Fe-rich regions are elongated along the axis of the AGN cavities, extending beyond their immediate scale. The Ne/Fe ratio in the core is consistent with solar (${\rm Ne/Fe} = 1.03^{+0.25}_{-0.23}$), arguing against the dust depletion scenario.
CommentsAccepted for publication in Astronomy & Astrophysics. 7 pages, 5 figures
