NASA/IPAC EXTRAGALACTIC DATABASE
Date and Time of the Query: 2019-04-23 T03:56:15 PDT
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For refcode 2009ApJ...705..454N:
Retrieve 23 NED objects in this reference.
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Copyright by American Astronomical Society. Reproduced by permission
2009ApJ...705..454N A New Sample of Buried Active Galactic Nuclei Selected from the Second XMM-Newton Serendipitous Source Catalogue Noguchi, Kazuhisa; Terashima, Yuichi; Awaki, Hisamitsu Abstract. 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 ~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 (~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. Key words: galaxies: active, galaxies: Seyfert, X-rays: galaxies
Retrieve 23 NED objects in this reference.
Please click here for ADS abstract

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