2009ApJ...696.1657E -
Astrophys. J., 696, 1657-1667 (2009/May-2)
Suzaku view of the Swift/BAT active galactic nuclei. I. Spectral analysis of six active galactic nuclei and evidence for two types of obscured population.
EGUCHI S., UEDA Y., TERASHIMA Y., MUSHOTZKY R. and TUELLER J.
Abstract (from CDS):
We present a systematic spectral analysis with Suzaku of six active galactic nuclei (AGNs) detected in the Swift/BAT hard X-ray (15-200 keV) survey: Swift J0138.6-4001, J0255.2-0011, J0350.1-5019, J0505.7-2348, J0601.9-8636, and J1628.1-5145. This is considered to be a representative sample of new AGNs without X-ray spectral information before the BAT survey. We find that the 0.5-200 keV spectra of these sources can be uniformly fitted with a base model consisting of heavily absorbed (log NH> 23.5/cm2) transmitted components, scattered lights, a reflection component, and an iron-K emission line. There are two distinct groups: three "new-type" AGNs (including the two sources reported by Ueda et al.) with an extremely small scattered fraction (fscat< 0.5%) and strong reflection component (R = Ω/2π ≳ 0.8, where Ω is the solid angle of the reflector), and three "classical-type" ones with fscat> 0.5% and R ≲ 0.8. The spectral parameters suggest that the new type has an optically thick torus for Thomson scattering (N H∼ 1025/cm2) with a small opening angle θ ∼ 20° viewed in a rather face-on geometry, while the classical type has a thin torus (NH ∼ 1023–24/cm2) with θ ≳ 30°. We infer that a significant number of new-type AGNs with an edge-on view are missing in the current all-sky hard X-ray surveys.
Abstract Copyright:
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Journal keyword(s):
galaxies: active - gamma rays: observations - X-rays: galaxies - X-rays: general
CDS comments:
Swift J1628.1-5145 is a misprint for Swift J1628.1+5145, which is Swift J1628.0+5144 in Simbad.
Simbad objects:
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