8th HEAD Meeting, 8-11 September, 2004
Session 32 AGN/Galactic Nuclei
Oral, Saturday, September 11, 2004, 9:00-10:30am

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[32.04] Chandra Observations of Highly Obscured AGN

N. A. Levenson (Univ. Kentucky), K. A. Weaver (GSFC/JHU), T. M. Heckman, J. H. Krolik (JHU), P. T. Zycki (N. Copernicus Astron. Ctr.)

X-ray selection is biased against finding strongly-obscured active galactic nuclei (AGN), yet up to half of all Seyfert 2 galaxies are Compton thick, with obscuring column densities that exceed 1024 cm-2. We analyze new Chandra observations of three Compton thick Seyfert 2s. We determine the physical conditions of their immediate circumnuclear regions, including column density, solid angle covering fraction, and viewing angle. The Fe K alpha line is prominent in these examples with equivalent width > 1 keV, which constrains these physical parameters.

In addition to their active nuclei, these galaxies show significant extended X-ray emission on physical scales smaller than 1 kpc, likely due to small jets and star formation. With these complications and the suppression of the emergent hard X-ray flux, simple techniques fail to accurately measure the intrinsic luminosity of these AGN and their obscuration. We discuss these results in the context of other heavily obscured AGN and develop diagnostics to determine their characteristics even when the data quality is poor.

This work is supported by NASA grant G04-5117 and NSF CAREER award AST-0237291.

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Bulletin of the American Astronomical Society, 36 #3
© 2004. The American Astronomical Soceity.