The 'clus' model in SPEX: Projection and resonant scattering effects on the iron abundance and temperature profiles of galaxy clusters

The uploaded files can be used to reproduce the dataset and figures in the paper The 'clus' model in SPEX: Projection and resonant scattering effects on the iron abundance and temperature profiles of galaxy clusters by Lýdia Štofanová, Aurora Simionescu, and Jelle Kaastra. This paper was accepted for a publication in Astronomy and Astrophysics journal on December 11th, 2024. NOTE: Files will be published with a new version. If the files are needed earlier, please contact me by email. ABSTRACT: In this paper we introduce the clus model, which has been newly implemented in the X-ray spectral fitting software package SPEX. Based on the 3D radial profiles of the gas density, temperature, metal abundance, turbulent, and inflow/outflow velocities, the clus model creates spectra for a chosen projected region on the sky. Additionally, it can also take into account the resonant scattering. We show a few applications of the clus model on simulated spectra of the massive elliptical galaxy NGC 4636, and galaxy clusters A383, A2029, A1795, A262, and the Perseus cluster. We quantify the effect of projection, as well as resonant scattering on inferred profiles of the iron abundance and temperature, assuming the resolution similar to Chandra ACIS-S and XRISM Resolve. Our results show that, depending on the mass of the object, as well as the projected distance from its core, neither a single-temperature, double-temperature, nor the Gaussian-shaped differential emission measure models can accurately describe the input emission measure distribution of these massive objects. The largest effect of projection as well as resonant scattering is seen for projected profiles of iron abundance of NGC 4636, where we are able to reproduce the observed iron abundance drop in its inner-most few kiloparsecs. Furthermore, we find that projection effects also influence the best-fit temperature, and the magnitude of this effect varies depending on the underlying hydrodynamical profiles of individual objects. In the core, the projection effects are the largest for A1795 and NGC 4636, while in the outskirts the largest difference between 2D and 3D temperature profiles are for Perseus and A1795, regardless of the instrumental resolution. These findings might potentially have an impact on cross-calibration studies between different instruments, as well as on the precision cosmology.上传的文件可用于复现论文《SPEX中的clus模型（clus model）：投影与共振散射对星系团（galaxy clusters）铁丰度（iron abundance）和温度剖面（temperature profiles）的影响》中的数据集与图表。该论文作者为Lýdia Štofanová、Aurora Simionescu与Jelle Kaastra，于2024年12月11日被《Astronomy and Astrophysics》（天文学与天体物理学）期刊接收发表。 注意：文件将以新版本发布。若需提前获取文件，请通过邮件联系本人。 摘要：本文介绍了新近在X射线光谱拟合软件包SPEX中实现的clus模型。该模型基于气体密度、温度、金属丰度、湍流以及流入/流出速度的三维径向剖面，可针对天空中选定的投影区域生成光谱。此外，它还可纳入共振散射效应。我们展示了clus模型在数个天体的模拟光谱上的应用案例：包括巨椭圆星系（elliptical galaxy）NGC 4636，以及星系团A383、A2029、A1795、A262与英仙座星系团。我们以近似钱德拉（Chandra）ACIS-S和XRISM Resolve的仪器分辨率为前提，量化了投影效应与共振散射对铁丰度和温度剖面反演结果的影响。 研究结果表明：根据天体质量以及距核心的投影距离的不同，单温度、双温度乃至高斯型微分发射量（differential emission measure）模型，均无法准确描述这类大质量天体的输入发射量分布（emission measure distribution）。投影与共振散射的最大效应体现在NGC 4636的铁丰度投影剖面上，我们借此成功复现了其最内侧数千秒差距（kiloparsecs）内观测到的铁丰度下降现象。此外，我们发现投影效应同样会影响最优拟合温度，且该效应的强弱取决于各天体自身的流体动力学剖面（hydrodynamical profiles）。在核心区域，A1795与NGC 4636的投影效应最为显著；而在外围区域，无论仪器分辨率如何，二维与三维温度剖面间的最大差异均出现在英仙座星系团与A1795中。上述发现或对不同仪器间的交叉定标（cross-calibration）研究，乃至精确宇宙学（precision cosmology）研究产生潜在影响。