标题： XRISM对Centaurus A中复杂Fe K$α$线的分析 显示英文标题

标题： XRISM analysis of the complex Fe K$α$ line in Centaurus A

摘要： 我们分析了邻近活动星系核Centaurus A的Fe K$\alpha$发射线的高分辨率XRISM/Resolve光谱。 该线具有两个窄而分辨的峰，分别为Fe K$\alpha_1$和Fe K$\alpha_2$，每个的FWHM为$(4.8\pm0.2)\times10^2$km/s。 还需要一个FWHM为$(4.3\pm0.3)\times10^3$km/s的宽线，其流量与两个窄线核心相似。 该宽成分在Cen A的光学或IR光谱中未被观测到。 线形要求存在一个从$\sim10^{-3}$pc延伸到$\sim10^1$pc的发射区域。 假设发射率遵循径向幂律分布$r^{-q}$，我们发现$q\approx2$。这可能表明存在一个扩展的日冕，一个朝向日冕弯曲的辐射区域，或者密度不均匀。当假设$q=3$时，只有在模型中包含三个辐射组分才能再现谱线形状。测得的最佳拟合倾角是$24^{+13}_{-7}$度，但更高的倾角仅被略微排除。单一的模糊 MYTorusL 谱线轮廓可以描述谱线形状，但需要较大的相对归一化。这可能是由于过去的变异性、修改后的丰度或不同的几何结构造成的。从回声映射测量的半径可以再现谱线形状，但前提是包括一个小半径处的额外扩展辐射区域。 显示英文摘要

摘要： We analyze the high-resolution XRISM/Resolve spectrum of the Fe K$\alpha$ emission line of the nearest active galactic nucleus, in Centaurus A. The line features two narrow and resolved peaks of Fe K$\alpha_1$, and Fe K$\alpha_2$ with a FWHM of $(4.8\pm0.2)\times10^2$ km/s each. A broad line with a FWHM of $(4.3\pm0.3)\times10^3$ km/s, and with a flux similar to the two narrow line cores, is also required. This broad component is not observed in the optical or IR spectra of Cen A. The line shape requires the existence of an emission region that extends from $\sim10^{-3}$ pc to $\sim10^1$ pc. Assuming that the emissivity follows a radial power-law profile of $r^{-q}$, we find $q\approx2$. This may indicate an extended corona, an emitting region that bends towards the corona, or a non-uniform density. When assuming $q=3$, the line shape can only be reproduced by including three emitting components in the model. The measured best-fit inclination is $24^{+13}_{-7}$ degrees, but higher inclinations are only slightly disfavored. A single blurred MYTorusL line profile can describe the line shape, but requires a large relative normalization. This could be due to past variability, modified abundances, or differing geometries. The line shape can be reproduced from the radii measured by reverberation mapping, but only if an additional extended emitting region at small radii is included.