A NEW SAMPLE OF BURIED ACTIVE GALACTIC NUCLEI SELECTED FROM THE SECOND XMM-NEWTON SERENDIPITOUS SOURCE CATALOGUE

Journal Article · Sun Nov 01 04:00:00 EST 2009 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/705/1/454· OSTI ID:21378375

Noguchi, Kazuhisa; Terashima, Yuichi; Awaki, Hisamitsu ^[1]

---

1. Department of Physics, Ehime University, Matsuyama, Ehime 790-8577 (Japan)

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 approx10{sup 23-24} cm{sup -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 (approx3%) 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] lambda5007 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.

• OSTI ID: 21378375
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 705; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
BOSONS
CATALOGS
COSMIC RADIATION
COSMIC RAY SOURCES
COSMIC X-RAY SOURCES
DOCUMENT TYPES
ELECTROMAGNETIC RADIATION
ELEMENTARY PARTICLES
GALAXIES
GALAXY NUCLEI
HARD X RADIATION
IONIZATION
IONIZING RADIATIONS
LUMINOSITY
MASSLESS PARTICLES
OPTICAL PROPERTIES
PHOTOIONIZATION
PHOTONS
PHYSICAL PROPERTIES
RADIATIONS
SCATTERING
SOFT COMPONENT
SPECTRA
X RADIATION
X-RAY GALAXIES
X-RAY SPECTRA