Remarkable Spectral Variability of PDS 456

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%).

submitted to ApJ

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Cited by in corpus (21)

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• A new relativistic component of the accretion disk wind in PDS 456
• Revealing the X-ray Variability of AGN with Principal Component Analysis
• Resolving the soft X-ray ultra fast outflow in PDS 456
• The Relative Rate of LGRB Formation as a Function of Metallicity
• Structured ionized winds shooting out from a quasar at relativistic speeds
• Discovery of Broad Soft X-ray Absorption Lines from the Quasar Wind in PDS 456
• Variable Nature of Magnetically-Driven Ultra-Fast Outflows
• A momentum conserving accretion disk wind in the narrow line Seyfert 1, I Zwicky 1
• Variability of the High Velocity Outflow in the Quasar PDS 456
• Relativistic components of the Ultra-Fast Outflow in the Quasar PDS 456 from Chandra/HETGS, NuSTAR and XMM-Newton observations
• The role of the Gamma-Eddington ratio relation on the X-ray Baldwin effect in Active Galactic Nuclei
• The flaring X-ray corona in the quasar PDS 456
• Decoupling absorption and continuum variability in the Seyfert 2 NGC 4507
• X-ray flaring in PDS 456 observed in a high-flux state
• Resolving the X-ray obscuration in a low flux observation of the quasar PDS 456
• Gamma-Ray Burst Afterglows as Analogues of High Frequency-Peaked BL Lac Objects
• Constraining X-ray Coronal Size with Transverse Motion of AGN Ultra-Fast Outflows