The Two-Phase Pair Corona Model for Active Galactic Nuclei and X-Ray Binaries: How to Obtain Exact Solutions

Poutanen, Juri; Svensson, Roger

doi:10.1086/177865

Cited by 468 publications

(497 citation statements)

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“…In the following, we quote statistical errors at the 1σ confidence level (∆χ 2 = 1 for one parameter of interest). We initially fitted our data using the Comptonization model COMPPS in XSPEC (see Poutanen & Svensson 1996) modified by the interstellar absorption (TBNEW in XSPEC, Wilms et al 2000) with a fixed column density of NH = 8.3 × 10 21 cm −2 . We left the Thomson optical depth τ electron temperature kTe and the normalization in COMPPS free to vary, while we fixed the seed photon temperature to kTbb = −0.1 keV (i.e.…”

Section: Treatment Of the Dust Scattering X-ray Halomentioning

confidence: 99%

The black hole binary V404 Cygni: a highly accreting obscured AGN analogue

Motta

Kajava

Sánchez–Fernández

et al. 2017

Monthly Notices of the Royal Astronomical Society

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Typical black hole binaries in outburst show spectral states and transitions, characterized by a clear connection between the inflow onto the black hole and outflows from its vicinity. The transient stellar mass black hole binary V404 Cyg apparently does not fit in this picture. Its outbursts are characterized by intense flares and intermittent plateau and low-luminosity states, with a dynamical intensity range of several orders of magnitude on time-scales of hours. During the 2015 June-July X-ray outburst a joint Swift and INTEGRAL observing campaign captured V404 Cyg in one of these plateau states. The simultaneous Swift/XRT and INTE-GRAL /JEM-X/ISGRI spectrum is reminiscent of that of obscured/absorbed AGN. It can be modelled as a Comptonization spectrum, heavily absorbed by a partial covering, high-column density material (N H ≈ 1 − 3 × 10 24 cm −2 ), and a dominant reprocessed component, including a narrow Iron-Kα line. Such spectral distribution can be produced by a geometrically thick accretion flow able to launch a clumpy outflow, likely responsible for both the high intrinsic absorption and the intense reprocessed emission observed. Similarly to what happens in certain obscured AGN, the low-flux states might not be (solely) related to a decrease in the intrinsic luminosity, but could instead be caused by an almost complete obscuration of the inner accretion flow.

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Section: Treatment Of the Dust Scattering X-ray Halomentioning

confidence: 99%

The black hole binary V404 Cygni: a highly accreting obscured AGN analogue

Motta

Kajava

Sánchez–Fernández

et al. 2017

Monthly Notices of the Royal Astronomical Society

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“…To estimate fluxes from the source, we have fitted the spectral data with a standard for BHs diskbb+powerlaw model and corrected the model fluxes in the specific energy bands by the ratio of the data to the model. For a more detailed spectral modelling we also fitted the data with a hybrid Comptonization model compps (Poutanen & Svensson 1996) and a cutoff power-law model with Compton reflection pexrav (Magdziarz & Zdziarski 1995). Interstellar absorption was taken into account using wabs model with the neutral hydrogen column density of NH = 0.80 × 10 22 cm −2 (Miller et al 2003).…”

Section: Datamentioning

confidence: 99%

Colours of black holes: infrared flares from the hot accretion disc in XTE J1550–564

Poutanen

Veledina

Revnivtsev

2014

Monthly Notices of the Royal Astronomical Society

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Outbursts of the black hole (BH) X-ray binaries are dramatic events occurring in our Galaxy approximately once a year. They are detected by the X-ray telescopes and often monitored at longer wavelengths. We analyse the X-ray and optical/infrared (OIR) light-curves of the BH binary XTE J1550-564 during the 2000 outburst. By using the observed extreme colours as well as the characteristic decay time-scales of the OIR and X-ray light curves, we put strong constraints on the extinction towards the source. We accurately separate the contributions to the OIR flux of the irradiated accretion disc and a non-thermal component. We show that the OIR non-thermal component appears during the X-ray state transitions both during the rising and the decaying part of the outburst at nearly the same X-ray hardness but at luminosities differing by a factor of 3. The line marking the quenching/recovery of the non-thermal component at the X-ray hardness-flux diagram seems to coincide with the 'jet line' that marks the presence of the compact radio jet. The inferred spectral shape and the evolution of the non-thermal component during the outburst, however, are not consistent with the jet origin, but are naturally explained in terms of the hybrid hot flow scenario, where non-thermal electrons emit synchrotron radiation in the OIR band. This implies a close, possibly causal connection between the presence of the hot flow and the compact jet. We find that the non-thermal component is hardening during the hard state at the decaying stage of the outburst, which indicates that the acceleration efficiency is a steep function of radius at low accretion rate.

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“…A physical model should include the processes of thermal Comptonisation. Here we apply the compPS model (Poutanen & Svensson 1996). We assume that the plasma of temperature T e forms an infinite slab on top of the accretion disk, with the plasma having an optical depth τ.…”

Section: The Hard X-ray Spectrummentioning

confidence: 99%

The hard X-ray emission of Centaurus A

Beckmann

Jean

Lubiński

et al. 2011

A&A

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Context. The radio galaxy Cen A has been detected all the way up to the TeV energy range. This raises the question about the dominant emission mechanisms in the high-energy domain. Aims. Spectral analysis allows us to put constraints on the possible emission processes. Here we study the hard X-ray emission, in order to distinguish between a thermal and a non-thermal inverse Compton process. Methods. Using hard X-ray data provided by INTEGRAL, we determined the cut-off of the power-law spectrum in the hard X-ray domain (3−1000 keV). In addition, INTEGRAL data are used to study the spectral variability. The extended emission detected in the gamma-rays by Fermi/LAT is investigated using the data of the spectrometre SPI in the 40−1000 keV range. Results. The hard X-ray spectrum of Cen A shows a significant cut-off at energies E C = 434 +106 −73 keV with an underlying power-law of photon index Γ = 1.73 ± 0.02. A more physical model of thermal Comptonisation (compPS) gives a plasma temperature of kT e = 206 ± 62 keV within the optically thin corona with Compton parameter y = 0.42 +0.09 −0.06 . The reflection component is significant at the 1.9σ level with R = 0.12 +0.09 −0.10 , and a reflection strength R > 0.3 can be excluded on a 3σ level. Time resolved spectral studies show that the flux, absorption, and spectral slope varied in the range f 3−30 keV = 1.2−9.2 × 10 −10 erg cm −2 s −1 , N H = 7−16 × 10 22 cm −2 , and Γ = 1.75−1.87. Extending the cut-off power-law or the Comptonisation model to the gamma-ray range shows that they cannot account for the high-energy emission. On the other hand, a broken or curved power-law model can also represent the data, therefore a non-thermal origin of the X-ray to GeV emission cannot be ruled out. The analysis of the SPI data provides no sign of significant emission from the radio lobes and gives a 3σ upper limit of f 40−1000 keV < ∼ 1.1 × 10 −3 ph cm −2 s −1 . Conclusions. While gamma-rays, as detected by CGRO and Fermi, are caused by non-thermal (jet) processes, the main process in the hard X-ray emission of Cen A is still not unambiguously determined, since it is either dominated by thermal inverse Compton emission or by non-thermal emission from the base of the jet.

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The Two-Phase Pair Corona Model for Active Galactic Nuclei and X-Ray Binaries: How to Obtain Exact Solutions

Cited by 468 publications

References 43 publications

The black hole binary V404 Cygni: a highly accreting obscured AGN analogue

The black hole binary V404 Cygni: a highly accreting obscured AGN analogue

Colours of black holes: infrared flares from the hot accretion disc in XTE J1550–564

The hard X-ray emission of Centaurus A

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