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

Journal Article · Sun May 10 00:00:00 EDT 2009 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/696/2/1657; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)· OSTI ID:21300647

Eguchi, Satoshi; Ueda, Yoshihiro ^[1]; Terashima, Yuichi ^[2]; Mushotzky, Richard; Tueller, Jack ^[3]

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1. Department of Astronomy, Kyoto University, Kyoto 606-8502 (Japan)
2. Department of Physics, Faculty of Science, Ehime University, Matsuyama 790-8577 (Japan)
3. NASA/Goddard Space Flight Center, Greenbelt, MD 20771 (United States)

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 N {sub H} > 23.5 cm{sup -2}) 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 (f {sub scat} < 0.5%) and strong reflection component (R = {omega}/2{pi} {approx}> 0.8, where {omega} is the solid angle of the reflector), and three 'classical-type' ones with f {sub scat} > 0.5% and R {approx}< 0.8. The spectral parameters suggest that the new type has an optically thick torus for Thomson scattering (N {sub H} {approx} 10{sup 25} cm{sup -2}) with a small opening angle {theta} {approx} 20 deg. viewed in a rather face-on geometry, while the classical type has a thin torus (N {sub H} {approx} 10{sup 23-24} cm{sup -2}) with {theta} {approx}> 30 deg. 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.

• OSTI ID: 21300647
• Journal Information: Astrophysical Journal, Vol. 696, Issue 2; Other Information: DOI: 10.1088/0004-637X/696/2/1657; Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE
GALAXY NUCLEI
GAMMA RADIATION
HARD X RADIATION
IRON
KEV RANGE
THOMSON SCATTERING
X-RAY GALAXIES