Multi-zone warm and cold clumpy absorbers in 3 Seyfert galaxies
We performed the spectral analysis of 3 Seyfert galaxies presenting evidence of a strong soft excess below 2 keV. We showed how this soft excess can be related only to a clumpy structure of the absorbers, and does not need any additional emission component.
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ABSTRACT
Aims. We present the first detailed X-ray analysis of three AGN, the Seyfert 1 galaxies UGC 3142 and ESO 140-43, and the Seyfert 2 galaxy ESO 383-18, in order to study the geometry and the physical characteristics of their absorbers.
Methods. High quality XMM-Newton EPIC and RGS data were analysed, as well as Swift/XRT and BAT and INTEGRAL IBIS/ISGRI data, in order to cover the 0.3-110 keV energy range. For ESO 140-43 also XMM-Newton/OM and Swift/UVOT data were used. We studied the variability of the three AGN on a time-scale of seconds using the EPIC/PN light curves, and the long-term time-scale variability of ESO 140-43 using two observations performed 6 months apart by XMM-Newton.
Results. The spectra of the three Seyfert galaxies present a "soft excess" at energies E < 2 keV above a power-law continuum that can be modeled by complex absorption, without any additional emission component. The X-ray sources in UGC 3142 and ESO 383-18 are absorbed by two layers of neutral material, with covering fractions f1 ≃ 0.92 and f2 ≃ 0.57 for UGC 3142, and f1 ≃ 0.97 and f2 ≃ 0.86 for ESO 383-18. While the clumpy absorber could be part of a disc wind or of the broad line region for UGC 3142, in the case of ESO 383-18 a clumpy torus plus Compton thin dust lanes are more likely. The spectra of ESO 140-43 can be well fitted using a power law absorbed by three clumpy ionized absorbers with different covering factors, column densities, and ionization parameters, likely part of a moving clumpy system, which might be a disc wind or the broad line region. The strong spectral and flux variability on a time scale of 6 months seen in ESO 140-43 is likely due to changes in the moving absorbers. The variation of the covering factor of one of the three ionized absorbers could be detected, on a kilo-seconds time-scale, in the EPIC light-curve of ESO 140-43.
Illustration of Black Hole with Accretion Disk and Torus
Artist's conception showing a black hole surrounded by a disk of hot gas, and a large doughnut or torus of cooler gas and dust. The light blue ring on the back of the torus is due to the fluorescence of iron atoms excited by X-rays from the hot gas disk.
Credits: NASA/CXC/M.Weiss
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