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See detailBlack hole spin and size of the X-ray-emitting region(s) in the Seyfert 1.5 galaxy ESO 362-G18
Agis-Gonzalez, Beatriz ULiege; Miniutti, G.; Kara, E. et al

in Monthly Notices of the Royal Astronomical Society (2014), 443

We report results from multi-epoch X-ray observations of the Seyfert 1.5 galaxy ESO 362-G18 performed between 2005 November and 2010 June. ESO 362-G18 generally exhibits the typical X-ray spectrum of type ... [more ▼]

We report results from multi-epoch X-ray observations of the Seyfert 1.5 galaxy ESO 362-G18 performed between 2005 November and 2010 June. ESO 362-G18 generally exhibits the typical X-ray spectrum of type 1 active galactic nuclei. A disc-reflection component accounts for broad residuals in the iron K band and above 10 keV, as well as for a significant soft excess. From our best-fitting reflection model, we measure a black hole spin a ≥ 0.92 at the 99.99 per cent confidence level. ESO 362-G18 is also (typically) mildly absorbed by a column of neutral gas. The absorber is variable and one observation, performed ˜2 months after a typical mildly absorbed one, is heavily absorbed by a cold column density of ˜ 3-4 × 10[SUP]23[/SUP] cm[SUP]-2[/SUP], nearly two orders of magnitude higher than that during any other observation. UV variability between the heavily absorbed observation and the others suggests that the absorber can be identified with a dusty, clumpy torus. The absorption variability time-scale enables us to locate the X-ray-emitting region within the innermost ˜50 gravitational radii. Such result holds not only for the X-ray continuum, but also for the soft excess. [less ▲]

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See detailThe properties of the clumpy torus and BLR in the polar-scattered Seyfert 1 galaxy ESO 323-G77 through X-ray absorption variability
Miniutti, G.; Sanfrutos, M.; Beuchert, T. et al

in Monthly Notices of the Royal Astronomical Society (2014), 437

We report results from multi-epoch (2006-2013) X-ray observations of the polar-scattered Seyfert 1 galaxy ESO 323-G77. The source exhibits remarkable spectral variability from months to years timescales ... [more ▼]

We report results from multi-epoch (2006-2013) X-ray observations of the polar-scattered Seyfert 1 galaxy ESO 323-G77. The source exhibits remarkable spectral variability from months to years timescales. The observed spectral variability is entirely due to variations of the column density of a neutral absorber towards the intrinsic nuclear continuum. The column density is generally Compton-thin ranging from a few times 10[SUP]22[/SUP] cm[SUP]-2[/SUP] to a few times 10[SUP]23[/SUP] cm[SUP]-2[/SUP]. However, one observation reveals a Compton-thick state with column density of the order of 1.5 × 10[SUP]24[/SUP] cm[SUP]-2[/SUP]. The observed variability offers a rare opportunity to study the properties of the X-ray absorber(s) in an active galaxy. We identify variable X-ray absorption from two different components, namely (i) a clumpy torus whose individual clumps have a density of ≤1.7 × 10[SUP]8[/SUP] cm[SUP]-3[/SUP] and an average column density of ˜4 × 10[SUP]22[/SUP] cm[SUP]-2[/SUP], and (ii) the broad-line region (BLR), comprising individual clouds with density of 0.1-8 × 10[SUP]9[/SUP] cm[SUP]-3[/SUP] and column density of 10[SUP]23[/SUP]-10[SUP]24[/SUP] cm[SUP]-2[/SUP]. The derived properties of the clumpy torus can also be used to estimate the torus half-opening angle, which is of the order of 47°. We also confirm the previously reported detection of two highly ionized warm absorbers with outflow velocities of 1000-4000 km s[SUP]-1[/SUP]. The observed outflow velocities are consistent with the Keplerian/escape velocity at the BLR. Hence, the warm absorbers may be tentatively identified with the warm/hot intercloud medium which ensures that the BLR clouds are in pressure equilibrium with their surroundings. The BLR line-emitting clouds may well be the cold, dense clumps of this outflow, whose warm/hot phase is likely more homogeneous, as suggested by the lack of strong variability of the warm absorber(s) properties during our monitoring. [less ▲]

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