Determination of the X-ray reflection emissivity profile of 1H 0707-495

Wilkins, D. R.; Fabian, A. C.

doi:10.1111/j.1365-2966.2011.18458.x

Cited by 139 publications

(174 citation statements)

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“…The relativistic line at E RelLine = 6.49 +0.05 −0.04 keV returns a broken emissivity profile with Q in = 7.2 +0.4 −0.9 and Q out < 2.3. Recall that broken emissivity profiles similar to the one found here is naturally expected when one suspects the black hole to be rapidly rotating and the corona to be compact [24,47,48]. The power-law index is found to be 1.69 +0.02 −0.04 and the spin is constrained to a = 0.82 +0.05 −0.09 (90% confidence).…”

Section: Baseline-simplesupporting

confidence: 59%

“…Initially assuming the latter, we change the emissivity profile of RelLine so that within a radius of 10r g the emissivity is Q in and beyond this radius it is described as Q out > 2. Such a broken powerlaw prescription for the emissivity profile is naturally expected when one suspects the black hole to be rapidly rotating and the corona to be compact [24,47,48]. The break at 10r g is motivated both theoretically [47] as well as observationally since this is the likely scale for the X-ray emitting region in RX J1131-1231 as measured using gravitational microlensing [31,20,16]; however, we note that allowing this parameter to be free does not change the results presented here as the break radius is not very well constrained.…”

Section: Combined "Microlensing-quiet" Images-b and Cmentioning

confidence: 99%

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Reflection from the strong gravity regime in a lensed quasar at redshift z = 0.658

Reis

Reynolds

Miller

et al. 2014

Nature

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The co-evolution of a supermassive black hole with its host galaxy[1] through cosmic time is encoded in its spin[2, 3, 4]. At z > 2, supermassive black holes are thought to grow mostly by merger-driven accretion leading to high spin. However, it is unknown whether below z ∼ 1 these black holes continue to grow via coherent accretion or in a chaotic manner [5], though clear differences are predicted [3,4] in their spin evolution. An established method[6] to measure the spin of black holes is via the study of relativistic reflection features [7] from the inner accretion disk. Owing to their greater distances, there has hitherto been no significant detection of relativistic reflection features in a moderateredshift quasar. Here, we use archival data together with a new, deep observation of a gravitationally-lensed quasar at z = 0.658 to rigorously detect and study reflection in this moderate-redshift quasar. The level of relativistic distortion present in this reflection spectrum enables us to constrain the emission to originate within 3 gravitational radii from the black hole, implying a spin parameter a = 0.87 +0.08 −0.15 at the 3σ level of confidence and a > 0.66 at the 5σ level. The high spin found here is indicative of growth via coherent accretion for this black hole, and suggests that black hole growth between 0.5 z 1 occurs principally by coherent rather than chaotic accretion episodes. 1When optically-thick material, e.g. an accretion disc, is irradiated by hard X-rays, some of the flux is reprocessed into an additional 'reflected' emission component, which contains both continuum emission and atomic features. The most prominent signature of reflection from the inner accretion disc is typically the relativistic iron Kα line (6.4-6.97 keV; rest frame) [8] and the Compton reflection hump [7] often peaking at 20 − 30 keV (rest-frame). However, the deep gravitational potential and strong Doppler shifts associated with regions around black holes will also cause the forest of soft X-ray emission lines in the ∼ 0.7 − 2.0 keV range to be blended into a smooth emission feature, providing a natural explanation for the "soft-excess" observed in the X-ray spectra of nearby active galactic nuclei (AGNs) [9,10]. Indeed, both the iron line and the soft excess can be used to provide insight into the nature of the central black hole and to measure its spin [10]. Prior studies have revealed the presence of a soft-excess in 90% of quasars at[11, 12] z 1.7, and broad Fe-lines are also seen in 25% of these objects [11,13], suggesting that reflection is also prevalent in these distant AGNs. However, due to the inadequate S/N resulting from their greater distances, the X-ray spectra of these quasars were necessarily modeled using simple phenomenological parameterizations [12,14].Gravitational lensing offers a rare opportunity to study the innermost relativistic region in distant quasars [15,16], by acting as a natural telescope and magnifying the light from these sources. Quasars located between 0.5 z 1 are considerably ...

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Section: Baseline-simplesupporting

confidence: 59%

Section: Combined "Microlensing-quiet" Images-b and Cmentioning

confidence: 99%

Reflection from the strong gravity regime in a lensed quasar at redshift z = 0.658

Reis

Reynolds

Miller

et al. 2014

Nature

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“…Together, the evidence points to the corona being compact (Fabian 2012;Reis & Miller 2013). Further evidence of a small physical size of the corona emerges from observations of the emissivity profile of the broad iron line (Wilkins & Fabian 2011) and from varying obscuration of the corona by clouds (Risaliti et al 2011;Sanfrutos et al 2013).…”

Section: Introductionmentioning

confidence: 92%

“…Wilkins & Fabian (2011) have used the emissivity profile of the iron line in several AGN to deduce the coronal illumination of the disc and thus indirectly constrain the size of the corona. In several cases the bulk of the coronal emission is tightly limited to a compact region above the centre of the disc, with radius r less than the height of the corona h, i.e.…”

Section: Discussionmentioning

confidence: 99%

Properties of AGN coronae in theNuSTARera

Fabian

Lohfink

Kara

et al. 2015

Mon. Not. R. Astron. Soc.

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358

433

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The focussing optics of NuSTAR have enabled high signal-to-noise spectra to be obtained from many X-ray bright Active Galactic Nuclei (AGN) and Galactic Black Hole Binaries (BHB). Spectral modelling then allows robust characterization of the spectral index and upper energy cutoff of the coronal power-law continuum, after accounting for reflection and absorption effects. Spectral-timing studies, such as reverberation and broad iron line fitting, of these sources yield coronal sizes, often showing them to be small and in the range of 3 to 10 gravitational radii in size. Our results indicate that coronae are hot and radiatively compact, lying close to the boundary of the region in the compactness -temperature (Θ − ℓ) diagram which is forbidden due to runaway pair production. The coincidence suggests that pair production and annihilation are essential ingredients in the coronae of AGN and BHB and that they control the shape of the observed spectra.

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“…The corona is inferred to extend to around 35r g over the disc in the narrow line Seyfert 1 galaxy 1H 0707-495 (Wilkins & Fabian 2011 and to around 10r g in IRAS 13224-3809 . To this end, Wilkins & Fabian (2013) also model the lag-frequency spectra that would arise from the reverberation of X-rays originating from an extended emitting region using Monte Carlo simulations of rays arising throughout an optically thin extended region, varying both its radial extent over the plane of the accretion disc and its vertical extent perpendicular to the disc plane.…”

Section: Beyond Point-source Models: Extended Coronaementioning

confidence: 99%

X-ray reverberation around accreting black holes

Uttley

Cackett

Fabian³

et al. 2014

Astron Astrophys Rev

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447

606

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Luminous accreting stellar mass and supermassive black holes produce power-law continuum X-ray emission from a compact central corona. Reverberation time lags occur due to light travel time-delays between changes in the direct coronal emission and corresponding variations in its reflection from the accretion flow. Reverberation is detectable using light curves made in different X-ray energy bands, since the direct and reflected components have different spectral shapes. Larger, lower frequency, lags are also seen and are identified with propagation of fluctuations through the accretion flow and associated corona. We review the evidence for X-ray reverberation in active galactic nuclei and black hole X-ray binaries, showing how it can be best measured and how it may be modelled. The timescales and energy-dependence of the high frequency reverberation lags show that much of the signal is originating from very close to the black hole in some objects, within a few gravitational radii of the event horizon. We consider how these signals can be studied in the future to carry out X-ray reverberation mapping of the regions closest to black holes.

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Determination of the X-ray reflection emissivity profile of 1H 0707-495

Cited by 139 publications

References 15 publications

Reflection from the strong gravity regime in a lensed quasar at redshift z = 0.658

Reflection from the strong gravity regime in a lensed quasar at redshift z = 0.658

Properties of AGN coronae in theNuSTARera

X-ray reverberation around accreting black holes

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