Spectral Properties of Heavily Obscured Seyfert Galaxies from the INTEGRAL All-Sky Survey

Semena, A.; Sazonov, S.; Krivonos, R.

doi:10.1134/s1063773719080085

Cited by 7 publications

(12 citation statements)

References 83 publications

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“…The best-fit model yields a soft power-law component, a hard power-law component, and a reflection component with photon indexes Γ = 1.5 ± 0.2, Γ = 1.8 ± 0.1, and Γ = 1.8 ± 0.1, respectively. The estimated column density absorption is N 𝐻 ∼ 1.0 ± 0.1 × 10 24 cm −2 , which is consistent with the findings of Shu et al (2007) and Semena et al (2019) for this galaxy.…”

Section: The Nuclear Emissionsupporting

confidence: 90%

“…There are a total of nine fitted emission lines, including neutral Fe K𝛼 emission with an equivalent width EW=0.77 keV, similar to that found in previous works (e.g., Semena et al 2019;Tanimoto et al 2022). Table 5 gives the best-fit parameters and the energies of fitted emission lines.…”

Section: The Nuclear Emissionsupporting

confidence: 62%

“…The emission from the SMBH was assumed to follow a power law with a high-energy cutoff, modeled with . The cutoff energy in AGNs is usually above 150 keV, but for this study we fixed it at 200 keV (Semena et al 2019). The absorption of the emission in the torus was modeled using the model.…”

Section: The Nuclear Emissionmentioning

confidence: 99%

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Deep Chandra Observations of ESO 428-G014. II. Spectral Properties and Morphology of the Large-scale Extended X-Ray Emission

Fabbiano

Paggi

Karovska

et al. 2018

ApJ

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We present a deep Chandra spectral and spatial study of the kpc-scale diffuse X-ray emission of the Compton thick (CT) AGN ESO428-G014. The entire spectrum is best fit with composite photoionization + thermal models. The diffuse emission is more extended at the lower energies (<3 keV). The smaller extent of the hard continuum and Fe Kα profiles imply that the optically thicker clouds responsible for this scattering may be relatively more prevalent closer to the nucleus. These clouds must not prevent soft ionizing X-rays from the AGN escaping to larger radii, in order to have photoionized ISM at larger radii. This suggests that at smaller radii there may be a larger population of molecular clouds to scatter the hard X-rays, as in the Milky Way. The diffuse emission is also significantly extended in the cross-cone direction, where the AGN emission would be mostly obscured by the torus in the standard AGN model. Our results suggest that the transmission of the obscuring region in the cross-cone direction is ~10% than in the conedirection. In the 0.3-1.5 keV band, the ratio of cross-cone to cone photons increases to ~84%, suggesting an additional soft diffuse emission component, disjoint from the AGN. This could be due to hot ISM trapped in the potential of the galaxy. The luminosity of this component ~5×10 38 erg s -1 is roughly consistent with the thermal component suggested by the spectral fits in the 170-900 pc annulus.

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Section: The Nuclear Emissionsupporting

confidence: 90%

Section: The Nuclear Emissionsupporting

confidence: 62%

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Deep Chandra Observations of ESO 428-G014. II. Spectral Properties and Morphology of the Large-scale Extended X-Ray Emission

Fabbiano

Paggi

Karovska

et al. 2018

ApJ

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“…As REFL in SPEX only accounts for neutral Fe, we fitted this line with a Gaussian (GAUS; for simplicity), freeing the normalisation, energy and line broadening, which improved the fit by ∆C = 130. A similar approach was taken by Semena et al (2019) for NGC 5643.…”

Section: Best Fitmentioning

confidence: 98%

Photoionisation modelling of the X-ray emission line regions within the Seyfert 2 AGN NGC 1068

Grafton-Waters

Branduardi‐Raymont

Mehdipour

et al. 2021

A&A

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Aims. We investigate the photoionised X-ray emission line regions (ELRs) within the Seyfert 2 galaxy NGC 1068 to determine if there are any characteristic changes between observations taken 14 years apart. Methods. We compared XMM-Newton observations collected in 2000 and 2014, simultaneously fitting the reflection grating spectrometer and EPIC-pn spectra of each epoch, for the first time, with the photoionisation model, PION, in SPEX. Results. We find that four PION components are required to fit the majority of the emission lines in the spectra of NGC 1068, with log ξ = 1−4, log NH > 26 m−2, and vout = −100 to −600 km s−1 for both epochs. Comparing the ionisation state of the components shows almost no difference between the two epochs, while there is an increase in the total equivalent column density. To estimate the locations of these plasma regions from the central black hole, we compare distance methods, excluding the variability arguments as there is no spectral change between observations. Although the methods are unable to constrain the distances for each plasma component, the locations are consistent with the narrow line region, with the possibility of the higher ionised component being part of the broad line region; we cannot conclude this for certain, but the photoionisation modelling does suggest this is possible. In addition, we find evidence for emission from collisionally ionised plasma, while previous analysis had suggested that collisional plasma emission was unlikely. However, although PION is unable to account for the Fe XVII emission lines at 15 and 17 Å, we do not rule out that photoexcitation is a valid processes to produce these lines as well. Conclusions. NGC 1068 has not changed, both in terms of the observed spectra or from our modelling, within the 14 year time period between observations. This suggests that the ELRs are fairly static relative to the 14 year time frame between observations, or there is no dramatic change in the spectral energy distribution, resulting from a lack of black hole variability.

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Section: Best Fitmentioning

confidence: 98%

Photoionisation Modelling of the X-ray Emission Line Regions within the Seyfert 2 AGN NGC 1068

Grafton-Waters,

Branduardi-Raymont,

Mehdipour

et al. 2021

Preprint

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Aims. We investigate the photoionised X-ray emission line regions (ELRs) within the Seyfert 2 galaxy NGC 1068 to determine if there are any characteristic changes between observations taken 14 years apart. Methods. We compared XMM-Newton observations collected in 2000 and 2014, simultaneously fitting the reflection grating spectrometer (RGS) and EPIC-pn spectra of each epoch, for the first time, with the photoionisation model, PION, in SPEX. Results. We find that four PION components are required to fit the majority of the emission lines in the spectra of NGC 1068, with log ξ = 1 − 4, log N H > 26 m -2 , and v out = −100 to −600 km s -1 for both epochs. Comparing the ionisation state of the components shows almost no difference between the two epochs, while there is an increase in the total equivalent column density. To estimate the locations of these plasma regions from the central black hole, we compare distance methods, excluding the variability arguments as there is no spectral change between observations. Although the methods are unable to constrain the distances for each plasma component, the locations are consistent with the narrow line region, with the possibility of the higher ionised component being part of the broad line region; we cannot conclude this for certain, but the photoionisation modelling does suggest this is possible. In addition, we find evidence for emission from collisionally ionised plasma, while previous analysis had suggested that collisional plasma emission was unlikely. However, although PION is unable to account for the Fe xvii emission lines at 15 and 17 Å, we do not rule out that photoexcitation is a valid processes to produce these lines as well. Conclusions. NGC 1068 has not changed, both in terms of the observed spectra or from our modelling, within the 14 year time period between observations. This suggests that the ELRs are fairly static relative to the 14 year time frame between observations, or there is no dramatic change in the spectral energy distribution, resulting from a lack of black hole variability.

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Spectral Properties of Heavily Obscured Seyfert Galaxies from the INTEGRAL All-Sky Survey

Cited by 7 publications

References 83 publications

Deep Chandra Observations of ESO 428-G014. II. Spectral Properties and Morphology of the Large-scale Extended X-Ray Emission

Deep Chandra Observations of ESO 428-G014. II. Spectral Properties and Morphology of the Large-scale Extended X-Ray Emission

Photoionisation modelling of the X-ray emission line regions within the Seyfert 2 AGN NGC 1068

Photoionisation Modelling of the X-ray Emission Line Regions within the Seyfert 2 AGN NGC 1068

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