Nov, 2009
A NEW SAMPLE OF BURIED ACTIVE GALACTIC NUCLEI SELECTED FROM THE SECOND XMM-NEWTON SERENDIPITOUS SOURCE CATALOGUE
ASTROPHYSICAL JOURNAL
- ,
- ,
- Volume
- 705
- Number
- 1
- First page
- 454
- Last page
- 467
- Language
- English
- Publishing type
- Research paper (scientific journal)
- DOI
- 10.1088/0004-637X/705/1/454
- Publisher
- IOP PUBLISHING LTD
We present the results of X-ray spectral analysis of 22 active galactic nuclei (AGNs) with a small scattering fraction selected from the Second XMM-Newton Serendipitous Source Catalogue using hardness ratios. They are candidates of buried AGNs, since a scattering fraction, which is a fraction of scattered emission by the circumnuclear photoionized gas with respect to direct emission, can be used to estimate the size of the opening part of an obscuring torus. Their X-ray spectra are modeled by a combination of a power law with a photon index of 1.5-2 absorbed by a column density of similar to 10(23-24) cm(-2), an unabsorbed power law, narrow Gaussian lines, and some additional soft components. We find that scattering fractions of 20 among 22 objects are less than a typical value (similar to 3%) for Seyfert 2s observed so far. In particular, those of eight objects are smaller than 0.5%, which are in the range for buried AGNs found in recent hard X-ray surveys. Moreover, [O III]lambda 5007 luminosities at given X-ray luminosities for some objects are smaller than those for Seyfert 2s previously known. This fact could be interpreted as a smaller size of optical narrow emission-line regions produced in the opening direction of the obscuring torus. These results indicate that they are strong candidates for the AGN buried in a very geometrically thick torus.
- Link information
- ID information
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- DOI : 10.1088/0004-637X/705/1/454
- ISSN : 0004-637X
- Web of Science ID : WOS:000270903200039