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arXiv · 1005.3052

Chandra monitoring of UGC 4203: the structure of the X-ray absorber

G. Risaliti·M. Elvis·S. Bianchi·G. Matt
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Abstract

We present a Chandra monitoring campaign of the highly variable Seyfert galaxy UGC 4203 (the "Phoenix Galaxy") which revealed variations in the X-ray absorbing column density on time scales of two weeks. This is the third, clear case, after NGC 1365 and NGC 7582, of dramatic N_H variability on short time scales observed in a "changing look" source, i.e. an AGN observed in the past in both a reflection-dominated and a Compton-thin state. The inferred limits on the distance of the X-ray absorber from the center suggest that the X-ray "torus" could be one and the same with the broad emission line region. This scenario, first proposed for an "ad-hoc" picture for NGC 1365, may be the common structure of the circumnuclear medium in AGN.

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G. Risaliti, M. Elvis, S. Bianchi, G. Matt. 2010-05-19. Chandra monitoring of UGC 4203: the structure of the X-ray absorber. https://doi.org/10.1111/j.1745-3933.2010.00873.x

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