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arXiv · 0912.4946

Remarkable Spectral Variability of PDS 456

Ehud Behar·Shai Kaspi·James Reeves·T. J. Turner·Richard Mushotzky·Paul T. O'Brien
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Abstract

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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Ehud Behar, Shai Kaspi, James Reeves, T. J. Turner, Richard Mushotzky, Paul T. O'Brien. 2009-12-25. Remarkable Spectral Variability of PDS 456. https://doi.org/10.1088/0004-637x%2F712%2F1%2F26

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