New, more detailed calculations of the emission spectra of the He-like K ALPHA complex of calcium, iron and nickel have been carried out using data from both distorted-wave and R-matrix calculations. The value of the GD ratio (an extended definition of the G ratio that accounts for the effect of resolved and unresolved satellite lines) is significantly enhanced at temperatures below the temperature of He-like maximum abundance. Furthermore it is shown that satellite lines are important contributors to the GD ratio such that GD/G>1 at temperatures well above the temperature of maximum abundance. These new calculations demonstrate, with an improved treatment of the KLn (n>=3) satellite lines, that K ALPHA satellite lines need to be included in models of He like spectra even at relatively high temperatures. The excellent agreement between spectra and line ratios calculated from R-matrix and distorted-wave data also confirms the validity of models based on distorted-wave data for highly charged systems, provided the effect of resonances are taken into account as independent processes.
Iron and Nickel properties in the X-ray reflecting region of the Circinus Galaxy
本文讨论了用XMM-牛顿法研究的圆规星系核X射线反射区铁和镍的性质。主要结果如下:a)从Fe K α边缘的深度,如果假设(非直接可见的)照明光谱是由BeppoSAX测量的,则测量到A_Fe=1.7的数值,相对于宇宙值(如Anders & Grevesse 1989)。如果一次幂律的斜率可以自由变化,(约1.2)。b)从Ni与Fe K α线通量比,发现0.055-0.075的镍与铁丰度比。c)Fe K β/K α通量比略低于预期,这可能是由于铁的温和电离(然而,铁不能比X电离得多)。d)钱德拉已经发现的Fe Ka康普顿肩的存在得到证实,其相对通量意味着康普顿厚物质。这进一步支持了具有吸收体的反射区域的识别。
Iron and Nickel Line Diagnostics for the Galactic Center Diffuse Emission
我们利用朱雀星上的X射线成像光谱仪(XIS)观测到了银河系中心(GC)的弥散X射线辐射。高能量分辨率和低背景轨道提供了GC扩散X射线(GCDX)的优异光谱。XIS在GCDX中发现了铁和镍的K壳层跃迁能量附近的许多发射线。最显著的特征是FeI K α在6.4 keV和K壳吸收边在7.1 keV,这是从中性和/或低电离态的铁,和K壳线在6.7 keV和6.9 keV的类He(FeXXV K α)和类氢(FeXXVI Ly α)离子的铁。此外,首次检测到中性或低电离镍(NiI K α)和类氦镍(NiXXVII K α)的K α线,以及FeI K β、FeXXV K β、FeXXVI Ly β、FeXXV K γ和FeXXVI Ly γ。线中心的能量和宽度的FeXXV K α和FeXXVI Ly α有利于碰撞激发(CE)等离子体的起源的GCDX。由FeXXV K α/ FeXXV K β的线通量比确定的电子温度与由FeXXV K α/FeXXVI Ly α确定的电离温度相似。因此,似乎GCDX等离子体接近电离平衡。6.7 keV的流量和温度分布的银经是平滑和单调的,在积分点源流量分布相反。这些事实支持的假设,GCDX是真正的扩散排放,而不是大量的未解决的点源的输出的集成。此外,我们的研究结果表明,铁的化学成分的星际气体附近的GC被限制在约3.5倍的太阳。
A study of the breakdown of the quasi-static approximation at high densities and its effect on the helium-like K ALPHA complex of nickel, iron, and calcium
Model Photospheres for Late-Type Stars from the Inversion of High-Resolution Spectroscopic Observations. Groombridge 1830 and Epsilon Eridani
一种反演技术,恢复LTE的一维模型光球晚型恒星,这是以前应用于太阳(Allenge Prieto et al. 1998),现在被用来重建,半经验,光球的较冷的矮星:金属贫乏的ESTA 1830和太阳金属量的活动星Eps Eri。我们发现的模型大气令人满意地再现所有考虑弱到中等中性线的金属,满足详细的铁的激发平衡,强线的翅膀,和光学连续谱的斜率。检索到的模型显示,在log tau <=-0.5的层中,温度梯度比通量常数模型大气略陡。我们认为,这些差异应该反映在通量常数模型中缺失的成分,并指出颗粒状的不均匀性作为最佳候选人。铁离子化平衡是很好地满足的模型,为1830年,但不是Eps的Eri,其中0.2德克斯之间的差异来自中性和单电离线的对数铁丰度可能信号偏离LTE。从中性线的经验模型得出的钙,钛,铬和铁的化学丰度与以前的分析通量常数大气结构的基础上没有太大的不同。