First Statistical Tests for Clumpy Tori Models: Constraints from RXTE monitoring of Seyfert AGN
Abstract
We present an analysis of multi-timescale variability in line-of-sight X-ray absorbing gas as a function of optical classification in a large sample of Seyfert AGN to derive the first X-ray statistical constraints for clumpy-torus models. We systematically search for discrete absorption events in the vast archive of RXTE monitoring of 55 nearby type Is and Compton-thin type IIs. We are sensitive to discrete absorption events due to clouds of full-covering, neutral/mildly ionized gas with columns >∼10^{22-25} cm^{-2} transiting the line of sight. Our results probe model parameter space complementary to that for eclipses observed with XMM-Newton, Suzaku, and Chandra. We detect 12 eclipse events in 8 objects, roughly tripling the number previously published from RXTE. Peak column densities span 4-26 × 10^{22} cm^{-2}. Event durations span hours to years. The column density profile for a cloud in NGC 3783 is doubly spiked, possibly indicating a cloud that is being tidally sheared. We infer clouds' distances from the black hole to span 0.3 - 140 × 10^4 R_{g}. Most clouds' distances are commensurate with the outer portions of the BLR, or the inner regions of infrared-emitting dusty tori. We discuss implications for cloud distributions in the context of clumpy-torus models.
- Publication:
-
The X-ray Universe 2014
- Pub Date:
- July 2014
- Bibcode:
- 2014xru..confE.129M