A <i>NuSTAR</i> census of coronal parameters in Seyfert galaxies

Tortosa, A.; Bianchi, S.; Marinucci, Andrea; Matt, Giorgio; Petrucci, P.-O.

doi:10.1051/0004-6361/201732382

Cited by 129 publications

(148 citation statements)

References 88 publications

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“…This is very similar to the constancy of the spectral shape of the emission from a hot optically thin corona in radiative equilibrium with the surrounding soft photon field (e.g. Haardt & Maraschi 1991;Haardt 1993;Petrucci et al 2000;Tortosa et al 2018).…”

Section: Dependences On ξ 0 N H and T Bbsupporting

confidence: 64%

Radiation spectra of warm and optically thick coronae in AGNs

Petrucci

Gronkiewicz

Różáńska

et al. 2020

A&A

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A soft X-ray excess above the 2-10 keV power law extrapolation is generally observed in AGN X-ray spectra. The origin of this excess is still not well understood. Presently there are two competitive models: blurred ionized reflection and warm Comptonisation. In the case of warm Comptonisation, observations suggest a corona temperature in the range 0.1-2 keV and a corona optical depth ∼10-20. Moreover, radiative constraints from spectral fits with Comptonisation models suggest that most of the accretion power should be released in the warm corona and the disk below is basically non-dissipative, radiating only the reprocessed emission from the corona. The true radiative properties of such a warm and optically thick plasma are not well-known, however. For instance, the importance of the Comptonisation process, the potential presence of strong absorption/emission features or the spectral shape of the output spectrum have been studied only very recently. We present in this paper simulations of warm and optically thick coronae using the titan radiative transfer code coupled with the noar Monte-Carlo code, the latter fully accounting for Compton scattering of continuum and lines. Illumination from above by a hard X-ray emission and from below by an optically thick accretion disk is taken into account as well as (uniform) internal heating. Our simulations show that for a large part of the parameter space, the warm corona with sufficient internal mechanical heating is dominated by Compton cooling and neither strong absorption nor emission lines are present in the outgoing spectra. In a smaller part of the parameter space, the calculated emission agrees with the spectral shape of the observed soft X-ray excess. Remarkably, this also corresponds to the conditions of radiative equilibrium of an extended warm corona covering almost entirely a non-dissipative accretion disk. These results confirm the warm Comptonisation as a valuable model that can explain the origin of the soft X-ray excess.

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Section: Dependences On ξ 0 N H and T Bbsupporting

confidence: 64%

Radiation spectra of warm and optically thick coronae in AGNs

Petrucci

Gronkiewicz

Różáńska

et al. 2020

A&A

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“…We note here that the cutoff energy is uncommonly low for an AGN, even compared with the lowest NuSTAR measurements (e.g., Baloković et al 2015;Ursini et al 2015;Tortosa et al 2016). This model generally has more uncertainty in the parameters; most notably, it places no constraint on the BH spin.…”

Section: Self-consistent Disk Reflection Modelsmentioning

confidence: 70%

Evidence for Relativistic Disk Reflection in the Seyfert 1h Galaxy/ULIRG IRAS 05189–2524 Observed by NuSTAR and XMM-Newton

Baloković

Walton

et al. 2017

ApJ

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We present a spectral analysis of the NuSTAR and XMM-Newton observations of the Seyfert 1h galaxy/ULIRG IRAS 05189-2524 taken in 2013. We find evidence for relativistic disk reflection in the broadband X-ray spectrum: a highly asymmetric broad Fe Kα emission line extending down to 3 keV and a Compton scattering component above 10 keV. Physical modeling with a self-consistent disk reflection model suggests that the accretion disk is viewed at an intermediate angle with a supersolar iron abundance, and a mild constraint can be put on the high-energy cutoff of the power-law continuum. We test the disk reflection modeling under different absorption scenarios. A rapid black hole spin is favored; however, we cannot place a model-independent tight constraint on the value. The high reflection fraction (  R ref 2.0-3.2) suggests that the coronal illuminating source is compact and close to the black hole (lying within 8.7 R g above the central black hole), where light-bending effects are important.

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“…This feature has been observed in a number of sources (see e.g. Zdziarski et al 2000;Perola et al 2002;Dadina 2008;Baumgartner et al 2013;Malizia et al 2014;Lubiński et al 2016), in particular from high-sensitivity measurements enabled by NuSTAR (Fabian et al 2015;Tortosa et al 2018). In addition to the primary emission, other spec-tral components are often observed, such as a hump at 20-30 keV interpreted as Compton reflection from the accretion disc or more distant material (see e.g.…”

Section: Introductionmentioning

confidence: 76%

NuSTAR/XMM–Newton monitoring of the Seyfert 1 galaxy HE 1143-1810

Ursini¹,

Petrucci

Bianchi

et al. 2020

A&A

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Aims. We test the two-corona accretion scenario for active galactic nuclei in the case of the 'bare' Seyfert 1 galaxy HE 1143-1810. Methods. We perform a detailed study of the broad-band UV-X-ray spectral properties and of the short-term variability of HE 1143-1810. We present results of a joint XMM-Newton and NuSTAR monitoring of the source, consisting of 5 × 20 ks observations, each separated by 2 days, performed in December 2017. Results. The source is variable in flux among the different observations, and a correlation is observed between the UV and X-ray emission. Moderate spectral variability is observed in the soft band. The time-averaged X-ray spectrum exhibits a cut-off at ∼ 100 keV consistent with thermal Comptonization. We detect an iron Kα line consistent with being constant during the campaign and originating from a mildly ionized medium. The line is accompanied by a moderate, ionized reflection component. A soft excess is clearly present below 2 keV and is well described by thermal Comptonization in a 'warm' corona with a temperature of ∼ 0.5 keV and a Thomson optical depth of ∼ 17 − 18. For the hot hard X-ray emitting corona, we obtain a temperature of ∼ 20 keV and an optical depth of ∼ 4 assuming a spherical geometry. A fit assuming a jet-emitting disc (JED) for the hot corona also provides a nice description of the broad-band spectrum. In this case, the data are consistent with an accretion rate varying between ∼ 0.7 and ∼ 0.9 in Eddington units and a transition between the outer standard disc and the inner JED at ∼ 20 gravitational radii. Conclusions. The broad-band high-energy data agree with an accretion flow model consisting of two phases: an outer standard accretion disc with a warm upper layer, responsible for the optical-UV emission and the soft X-ray excess, and an inner slim JED playing the role of a hard X-ray emitting hot corona.

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A NuSTAR census of coronal parameters in Seyfert galaxies

Cited by 129 publications

References 88 publications

Radiation spectra of warm and optically thick coronae in AGNs

Radiation spectra of warm and optically thick coronae in AGNs

Evidence for Relativistic Disk Reflection in the Seyfert 1h Galaxy/ULIRG IRAS 05189–2524 Observed by NuSTAR and XMM-Newton

NuSTAR/XMM–Newton monitoring of the Seyfert 1 galaxy HE 1143-1810

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