PDS 456的显著光谱变化
Remarkable Spectral Variability of PDS 456
摘要：
我们报告的最高迄今为止的信号噪声比X射线光谱的发光类星体PDS 456，在两个XMM牛顿轨道在2007年9月获得。目前的光谱与自1998年以来PDS 456记录的几个先前的X射线光谱有很大不同。最近在2007年2月看到的超高速外流在吸收中没有检测到。相反，检测到显著的反射分量。反射模型表明反射介质可能以速度v/c = -0.06 +/-0.02流出。目前的光谱分析的背景下，在一个单一的模型的框架内，试图了解所有的光谱。我们检查是否流出与可变的部分覆盖的X射线源沿视线，也反映了从其他视线的源可以解释PDS 456的宽带光谱曲率的戏剧性变化。据确定，吸收在塑造其他时期的光谱中起着主要作用，而2007年XMM-牛顿光谱主要是反射，并且假定流出的源覆盖范围很小（< 20%）。
英文摘要：
We report on the highest to date signal-to-noise-ratio X-ray spectrum of the luminous quasar PDS 456, as obtained during two XMM-Newton orbits in September 2007. The present spectrum is considerably different from several previous X-ray spectra recorded for PDS 456 since 1998. The ultra-high-velocity outflow seen as recently as February 2007 is not detected in absorption. Conversely, a significant reflection component is detected. The reflection model suggests the reflecting medium may be outflowing at a velocity v/c = -0.06 +/- 0.02. The present spectrum is analyzed in the context of the previous ones in an attempt to understand all spectra within the framework of a single model. We examine whether an outflow with variable partial covering of the X-ray source along the line of sight that also reflects the source from other lines of sight can explain the dramatic variations in the broad-band spectral curvature of PDS 456. It is established that absorption plays a major role in shaping the spectrum of other epochs, while the 2007 XMM-Newton spectrum is dominated by reflection, and the coverage of the source by the putative outflow is small (< 20%).
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