THE SUZAKU VIEW OF 3C 382
- Department of Physics and Astronomy, MS 3F3, 4400 University Drive, George Mason University, Fairfax, VA 22030 (United States)
- X-ray Astrophysics Laboratory and CRESST, NASA/Goddard Space Flight Center, Greenbelt, MD 20771 (United States)
- Astrophysics Group, School of Physical and Geographical Sciences, Keele University, Keele, Staffordshire ST5 5BG (United Kingdom)
- Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom)
- Instituto de Fisica de Cantabria (CSIC-UC), 39005 Santander (Spain)
- Department of Astronomy, University of Maryland, College Park, MD 20742 (United States)
We present a long (116 ks) Suzaku observation of the broad-line radio galaxy (BLRG) 3C 382 acquired in 2007 April. A Swift BAT spectrum in 15-200 keV from the 58 month survey is also analyzed, together with an archival XMM-Newton EPIC exposure of 20 ks obtained one year after Suzaku. Our main result is the finding with Suzaku of a broad Fe K line with a relativistic profile consistent with emission from an accretion disk at tens of gravitational radii from the central black hole. The XIS data indicate emission from highly ionized iron and allow us to set tight, albeit model-dependent, constraints on the inner and outer radii of the disk reflecting region, r{sub in} {approx_equal} 10 r{sub g} and r{sub out} {approx_equal} 20 r{sub g} , respectively, and on the disk inclination, i {approx_equal} 30{sup 0}. Two ionized reflection components are possibly observed, with similar contributions of {approx}10% to the total continuum-a highly ionized one, with log{xi} {approx_equal} 3 erg s{sup -1} cm, which successfully models the relativistic line, and a mildly ionized one, with log{xi} {approx_equal} 1.5 erg s{sup -1} cm, which models the narrow Fe K{alpha} and high energy hump. When both these components are included, there is no further requirement for an additional blackbody soft excess below 2 keV. The Suzaku data confirm the presence of a warm absorber previously known from grating studies. After accounting for all the spectral features, the intrinsic photon index of the X-ray continuum is {Gamma}{sub x} {approx_equal} 1.8 with a cutoff energy at {approx}200 keV, consistent with Comptonization models and excluding jet-related emission up to these energies. Comparison of the X-ray properties of 3C 382 and other BLRGs to Seyferts recently observed with Suzaku and BAT confirms the idea that the distinction between radio-loud and radio-quiet active galactic nucleus at X-rays is blurred. The two classes form a continuum distribution in terms of X-ray photon index, reflection strength, and Fe K line width (related to the disk emission radius), with BLRGs clustered at one end of the distribution. This points to a common structure of the central engine, with only a few fundamental parameter(s) responsible for the radio-loud/radio-quiet division. The black hole spin, and in particular its rotation compared to the disk's, may be a key one.
- OSTI ID:
- 21576607
- Journal Information:
- Astrophysical Journal, Vol. 734, Issue 2; Other Information: DOI: 10.1088/0004-637X/734/2/105; ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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