On the Lamppost Model of Accreting Black Holes

Niedźwiecki, A.; Zdziarski, A. A.; Szanecki, Michał

doi:10.3847/2041-8205/821/1/l1

Cited by 59 publications

(61 citation statements)

References 39 publications

(56 reference statements)

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“…For a given static reflection model, they can be taken into account, e.g., using the relconv model (Dauser et al 2010). In the case of xillver, the relativistic effects are taken into account by relxill (but see Niedźwiecki et al 2016). Still, relxill defines the reflec- Figure B2.…”

Section: Discussionmentioning

confidence: 99%

“…However, this does not affect our determination of other parameters of the system. Furthermore, Niedźwiecki, Zdziarski & Szanecki (2016) have pointed out that the direct emission is not redshifted in the relxill and relxilllp models, and photons reflected by the disc and returning to it due to light bending are not taken into account. However, our results show only the presence of only moderate relativistic effects in GX 339-4; thus, those issues do not affect our results.…”

Section: Caveatsmentioning

confidence: 99%

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Spectral analysis of theXMM–Newtondata of GX 339–4 in the low/hard state: disc truncation and reflection

Basak¹,

Zdziarski²

2016

Mon. Not. R. Astron. Soc.

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We analyse all available observations of GX 339-4 by XMM-Newton in the hard spectral state. We jointly fit the spectral data by Comptonization and the currently best reflection code, relxill. We consider in detail a contribution from a standard blackbody accretion disc, testing whether its inner radius can be set equal to that of the reflector. However, this leads to an unphysical behaviour of the disc truncation radius, implying the soft X-ray component is not a standard blackbody disc. This appears to be due to irradiation by the hard X-rays, which strongly dominate the total emission. We consider a large array of models, testing, e.g., the effects of the chosen energy range, of adding unblurred reflection, and assuming a lamppost geometry. We find the effects of relativistic broadening to be relatively weak in all cases. In the coronal models, we find the inner radius to be large. In the lamppost model, the inner radius is unconstrained, but when fixed to the innermost stable orbit, the height of the source is large, which also implies a weak relativistic broadening. In the former models, the inner radius correlates with the X-ray hardness ratio, which is consistent with the presence of a truncated disc turning into a complete disc in the soft state. We also find the degree of the disc ionization to anti-correlate with the hardness, leading to strong spectral broadening due to scattering of reflected photons in the reflector in the softest studied states.

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Section: Discussionmentioning

confidence: 99%

Section: Caveatsmentioning

confidence: 99%

Spectral analysis of theXMM–Newtondata of GX 339–4 in the low/hard state: disc truncation and reflection

Basak¹,

Zdziarski²

2016

Mon. Not. R. Astron. Soc.

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“…Niedźwiecki et al 2016;Dovciak and Done 2015;Dovčiak and Done 2016). The lamppost model has also been applied in reflection studies of weakly magnetized NSs (e.g.…”

Section: Coronaementioning

confidence: 99%

Accretion Disks and Coronae in the X-Ray Flashlight

et al. 2017

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Plasma accreted onto the surface of a neutron star can ignite due to unstable thermonuclear burning and produce a bright flash of X-ray emission called a Type-I X-ray burst. Such events are very common; thousands have been observed to date from over a hundred accreting neutron stars. The intense, often Eddington-limited, radiation generated in these thermonuclear explosions can have a discernible effect on the surrounding accretion flow that consists of an accretion disk and a hot electron corona. Type-I X-ray bursts can there- fore serve as direct, repeating probes of the internal dynamics of the accretion process. In this work we review and interpret the observational evidence for the impact that Type-I X-ray bursts have on accretion disks and coronae. We also provide an outlook of how to make further progress in this research field with prospective experiments and analysis techniques, and by exploiting the technical capabilities of the new and concept X-ray missions ASTROSAT, NICER, Insight-HXMT, eXTP, and STROBE-X.

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“…The fact that the observed reflection fraction is constant suggests that the geometry does not change significantly, strengthening the interpretation in which the E c variations are intrinsic to the plasma. Also, the inner radius we measure is relatively large, so GR effects are present but not extreme, and therefore the discussion of relativistic modeling in Niedźwiecki et al (2016) is not applicable in this work.…”

Section: Physical Interpretationmentioning

confidence: 99%

“…Before discussing the details of the plasma physics, it is worth mentioning the possibility that the changes in E c may not be due to changes in the intrinsic election temperature, but rather due to changes in the gravitational redshift of a constant spectrum (e.g., Niedźwiecki et al 2016). Such changes in the gravitational redshift of the emitted photons (due to changes in the size of the corona, for instance) could artificially introduce variations in E c without the plasma properties changing.…”

Section: Physical Interpretationmentioning

confidence: 99%

A Long Look at MCG-5-23-16 with NuSTAR. I. Relativistic Reflection and Coronal Properties

Zoghbi

Matt

Miller

et al. 2017

ApJ

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MCG-5-23-16 was targeted in early 2015 with a half mega-secondobserving campaign using NuSTAR. Here we present the spectral analysis of these data sets along with an earlier observation and study the relativistic reflection and the primary coronal source. The data show strong reflection features in the form of both narrow and broad iron lines plus a Compton reflection hump. A cutoff energy is significantly detected in all exposures. The shape of the reflection spectrum does not change in the two years spanned by the observations, suggesting a stable geometry. A strong positive correlation is found between the cutoff energy and both the hard X-ray flux and spectral index. The measurements imply that the coronal plasma is not at the runaway electron-positron pair limit, and instead contains mostly electrons. The observed variability in the coronal properties is driven by a variable optical depth. A constant heating-to-cooling ratio is measured, implying that there is a feedback mechanism in which a significant fraction of the photons cooling the corona are due to reprocessed hard X-rays.

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On the Lamppost Model of Accreting Black Holes

Cited by 59 publications

References 39 publications

Spectral analysis of theXMM–Newtondata of GX 339–4 in the low/hard state: disc truncation and reflection

Spectral analysis of theXMM–Newtondata of GX 339–4 in the low/hard state: disc truncation and reflection

Accretion Disks and Coronae in the X-Ray Flashlight

A Long Look at MCG-5-23-16 with NuSTAR. I. Relativistic Reflection and Coronal Properties

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