We present an extraordinary variation of the X-ray spectrum of the obscured AGN in NGC 1365, which was observed by Chandra to change from Compton-thin to Compton-thick and back to Compton-thin in four days. This fast variation imply a a size of ~10^14 cm for the emitting region, and an extremely compact size (~10^16 cm) of the clumpy circumnuclear absorber.
@article{arxiv.astro-ph/0701108,
title = {X-ray observations of NGC 1365: time-resolved eclipse of the X-ray source},
author = {G. Risaliti},
journal= {arXiv preprint arXiv:astro-ph/0701108},
year = {2007}
}
Comments
Four pages, two figures. Conference proceedings to appear in "The Central Engine of Active Galactic Nuclei", ed. L. C. Ho and J.-M. Wang (San Francisco: ASP)