Bounds on the inner radius of emission around supermassive black holes

Journal Article · Wed Apr 01 04:00:00 EST 1998 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.55869· OSTI ID:641307

Bromley, B C ^[1]; Miller, W A ^[2]; Pariev, V I ^[3]; Pariev, V I ^[4]

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1. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, Massachusetts 02138 (United States)
2. Theoretical Astrophysics, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)
3. Steward Observatory, University of Arizona, 933 N. Cherry Ave., Tucson, Arizona 85721 (United States)
4. P. N. Lebedev Physical Institute, Leninsky Prospect 53, Moscow 117924 (Russia)

Observations of iron K-alpha fluorescence lines in Seyfert galaxies provide strong evidence for an accretion disk around a supermassive black hole as the source of the line emission. Here we consider a diagnostic of a disk line profile, based on the minimum and maximum frequency of emission, to robustly constrain the inner radius of the disk. This diagnostic is applied to spectra from Seyfert I galaxies (Iwasawa {ital et al.} 1996 [1]; Nandra {ital et al.} 1997 [2]), and a composite Seyfert II spectrum (Turner {ital et al.} 1997 [3]). We are able to place firm bounds on the inner radius of emission from the bright nucleus in MCG{endash}6{endash}30{endash}15; we find that the disk extends to within 6.2thinspR{sub g} of the central black hole, independent of inclination angle (R{sub g} is GM/c{sup 2} for a black hole of mass {ital M}). With inclination angle constraints{emdash}we find 29{plus_minus}5{degree} from frequency extrema of the [1] data{emdash}the inner radius bounded by 5.2{plus_minus}0.6thinspR{sub g}. The frequency extrema of composite Seyfert I and II spectra both show inner radii below about 20thinspR{sub g} and are consistent with modest inclination angles (i{lt}45 degrees). Hence, at the present noise level, the data do not support Seyfert unification models based on orientation effects. {copyright} {ital 1998 American Institute of Physics.}

• Sponsoring Organization: USDOE
• OSTI ID: 641307
• Report Number(s): CONF-9710168--
• Journal Information: AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Journal Issue: 1 Vol. 431; ISSN 0094-243X; ISSN APCPCS
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
ACCRETION DISKS
BLACK HOLES
FLUORESCENCE
LINE WIDTHS
SEYFERT GALAXIES
X-RAY SPECTRA