X-ray Reverberation Mapping: Ark 564

Recent progress mapping AGN accretion disks reveals Xray continuumreverberation from material at a few hundred Schwarzschild radii in NGC 4051. Wehave further demonstrated that claims of reverberation in 1H0707495 fromultrasmall radii, on the scale of the event horizon, are incorrect: like NGC4051, this AGN may be understood as exhibiting Xray reverberation from materialfurther out. Ark 564 is known to exhibit large time delays when analyzed overlong timescales, and, like 1H0707495, shows negative time lags on the fastestvariability timescales. We propose eight 55 ks observations of Ark 564 tothoroughly test the reverberation model, measure the transfer function and toderive strong constraints on the location and distribution of the Xray reprocessor. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]