Suzaku observations of iron lines and reflection in AGN

Reeves, J. N.; Fabian, A. C.; Kataoka, J.; Kunieda, H.; Markowitz, A.; Miniutti, G.; Okajima, Takashi; Serlemitsos, P. J.; Takahashi, Tadayuki; Terashima, Yuichi; Yaqoob, T.

doi:10.1002/asna.200610696

Cited by 31 publications

(42 citation statements)

References 31 publications

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“…This behavior was in fact detected in several AGN with Suzaku (Reeves et al 2006). The reason for the lack of strong variability in the reflection component is still unknown.…”

Section: The Origin Of the Fe Kα Linementioning

confidence: 84%

The warm absorber in NGC 5548

Detmers¹,

Kaastra

Costantini³

et al. 2008

A&A

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We study the variability of the warm absorber and the gas responsible for the emission lines in the Seyfert 1 galaxy NGC 5548 to constrain the location and physical properties of these components. Using X-ray spectra acquired using the Chandra-LETGS in 2002 and 2005, we study the variability of the ionic column densities and line intensities. We measure a lower O vii forbidden emission line flux in 2005, while the Fe Kα line flux remains constant. The warm absorber is less ionized in 2005, which enbles its location to be constrained to within 7 pc of the central source. Using both the observed variability and the limit on the FWHM of the O vii f line, we constrain the location of the narrow line region to a distance of 1 pc from the central source. The apparent lack of variability in the Fe Kα line flux does enable a unique explanation to be derived.

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“…This behavior was in fact detected in several AGN with Suzaku (Reeves et al 2006). The reason for the lack of strong variability in the reflection component is still unknown.…”

Section: The Origin Of the Fe Kα Linementioning

confidence: 84%

The warm absorber in NGC 5548

Detmers¹,

Kaastra

Costantini³

et al. 2008

A&A

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“…While the bandpass of XMM–Newton is limited to 12 keV, Suzaku is suited to observing the high‐energy X‐ray spectra above 10 keV. The only two narrow‐line objects that have been observed with Suzaku are NGC 7469 (Patrick et al 2011) and NGC 2110 (Reeves et al 2006). The hard X‐ray fluxes in both are consistent with the predictions of Model SRI using the parameters listed in Table 3.…”

Section: Discussionmentioning

confidence: 99%

On the apparent absence of broad iron lines in Seyfert galaxies

Bhayani

Nandra

2011

Monthly Notices of the Royal Astronomical Society

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We present an analysis of XMM-Newton observations of eleven Seyfert galaxies that appear to be missing a broad iron K alpha line. These objects represent a challenge to the established paradigm for active galactic nuclei, where a relatively cold accretion disc feeds the central black hole. In that paradigm, X-ray illumination of the accretion disc should lead to continuum and fluorescence emission from iron which is broadened and shifted by relativistic effects close the hole. We extend the work of Nandra et al. (2007), who found no evidence for such a component in an earlier analysis of these objects, by testing a variety of more complex relativistic reflection models. Specifically, we consider the possibility that the disc is highly ionised, and/or that the the reflection is heavily blurred by strong relativistic effects in a Kerr geometry. We find that in 8/11 of the observations with no apparent broad iron line, the fit is significantly improved when an ionised or strongly blurred reflector is included, and that all 11 observations allow for such a component. The disc inclinations are found generally to be around 60 degrees, which when combined with a steep emissivity profile results in strong relativistic blurring of the reflection, rendering the K alpha line difficult to distinguish from the underlying continuum. Nevertheless, relativistic reflection does appear to be present, and the strength of the smeared reflection is similar to that expected from a flat disc illuminated by a point source. Such blurred reflection and the associated steep radial emissivity profiles are consistent with the gravitational light bending of the continuum photons close to the black hole.Comment: 9 pages, 2 figures. Accepted for publication in MNRA

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“…Our models and fits are consistent with the values implied by spectral fits to the Fe lines of most AGNs. Assuming power-law distributions /r Àq for emissivity, the values of the index q obtained for MCG À5-23-13, NGC 4051, and NGC 3516 in recent Suzaku observations ( Reeves et al 2006) are q ' 2Y3; our models can accommodate easily the lower values of q while demanding a reasonably high degree of anisotropy for values q k 3. However, the disk illumination under the assumptions considered in this paper cannot account for the width of the Fe line profile of MCG À6-30-15, as obtained either by XMM-Newton (Wilms et al 2001;Fabian et al 2002) or more recently by Suzaku (Miniutti et al 2007), which demand a very steep (q ' 4:6) illumination of the inner disk section along with a flatter one (q ' 2:6) at larger radii.…”

Section: Discussionmentioning

confidence: 99%

Accretion Disk Illumination in Schwarzschild and Kerr Geometries: Fitting Formulae

Fukumura

Kazanas

2007

ApJ

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We describe the methodology and compute the illumination of geometrically thin accretion disks around black holes of arbitrary spin parameter a exposed to the radiation of a pointlike isotropic source at arbitrary height above the disk on its symmetry axis. We then provide analytic fitting formulae for the illumination as a function of the source height h and the black hole angular momentum a. We find that for a source on the disk symmetry axis and with h/M > 3, the main effect of the parameter a is allowing the disk to extend to smaller radii (approaching r/M ! 1 as a/M ! 1) and thus allowing the illumination of regions of much higher rotational velocity and redshift. We also compute the illumination profiles for anisotropic emission associated with the motion of the source relative to the accretion disk and present the fractions of photons absorbed by the black hole, intercepted by the disk, or escaping to infinity for both isotropic and anisotropic emission for a/M ¼ 0 and 0.99. As the anisotropy (of a source approaching the disk) increases, the illumination profile reduces (approximately) to a single power law, whose index q, because of absorption of the beamed photons by the black hole, saturates to a value no higher than q k 3. Finally, we compute the fluorescent Fe line profiles associated with the specific illumination and compare them among various cases.

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Suzaku observations of iron lines and reflection in AGN

Cited by 31 publications

References 31 publications

The warm absorber in NGC 5548

The warm absorber in NGC 5548

On the apparent absence of broad iron lines in Seyfert galaxies

Accretion Disk Illumination in Schwarzschild and Kerr Geometries: Fitting Formulae

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