X-ray Characteristics of NGC 3516: A View through the Complex Absorber

TL;DR

This study analyzes Suzaku and other X-ray data of NGC 3516, revealing that its variability is primarily driven by changes in line-of-sight absorption rather than intrinsic continuum fluctuations, challenging typical reverberation models.

Contribution

It provides new insights into the variability mechanisms of NGC 3516, emphasizing the role of absorption changes over intrinsic emission variations.

Findings

Absence of positive X-ray lag in NGC 3516 contrasts with other Seyferts.

Flux variations are dominated by absorption, not intrinsic continuum changes.

Colorless flux variations linked to crossing Compton-thick gas clumps.

Abstract

We consider new Suzaku data for NGC 3516 taken during 2009, along with other recent X-ray observations of the source. The cumulative characteristics of NGC 3516 cannot be explained without invoking changes in the line-of-sight absorption. Contrary to many other well-studied Seyfert galaxies, NGC 3516 does not show a positive lag of hard X-ray photons relative to soft photons over the timescales sampled. In the context of reverberation models for the X-ray lags, the lack of such a signal in NGC 3516 is consistent with flux variations being dominated by absorption changes. The lack of any reverberation signal in such a highly variable source disfavors intrinsic continuum variability in this case. Instead, the colorless flux variations observed at high flux states for NGC 3516 are suggested to be a consequence of Compton-thick clumps of gas crossing the line-of-sight.