A Variable-Density Absorption Event in NGC 3227 mapped with Suzaku and Swift
| Autor: | Beuchert, T., Markowitz, A. G., Krauß, F., Miniutti, G., Longinotti, A. L., Guainazzi, M., de La Calle, I., Malkan, M., Elvis, M., Miyaji, T., Hiriart, D., López, J. M., Agudo, I., Dauser, T., Garcia, J., Kreikenbohm, A., Kadler, M., Wilms, J. |
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| Rok vydání: | 2015 |
| Předmět: | |
| Zdroj: | A&A 584, A82 (2015) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1051/0004-6361/201526790 |
| Popis: | The morphology of the circumnuclear gas accreting onto supermassive black holes in Seyfert galaxies remains a topic of much debate. As the innermost regions of Active Galactic Nuclei (AGN) are spatially unresolved, X-ray spectroscopy, and in particular line-of-sight absorption variability, is a key diagnostic to map out the distribution of gas. Observations of variable X-ray absorption in multiple Seyferts and over a wide range of timescales indicate the presence of clumps/clouds of gas within the circumnuclear material. Eclipse events by clumps transiting the line of sight allow us to explore the properties of the clumps over a wide range of radial distances from the optical/UV Broad Line Region (BLR) to beyond the dust sublimation radius. Time-resolved absorption events have been extremely rare so far, but suggest a range of density profiles across Seyferts. We resolve a weeks-long absorption event in the Seyfert NGC 3227. We examine six Suzaku and twelve Swift observations from a 2008 campaign spanning 5 weeks. We use a model accounting for the complex spectral interplay of three differently-ionized absorbers. We perform time-resolved spectroscopy to discern the absorption variability behavior. We also examine the IR-to-X-ray spectral energy distribution (SED) to test for reddening by dust. The 2008 absorption event is due to moderately-ionized ($\log \xi\sim 1.2-1.4$) gas covering 90% of the line of sight. We resolve the density profile to be highly irregular, in contrast to a previous symmetric and centrally-peaked event mapped with RXTE in the same object. The UV data do not show significant reddening, suggesting that the cloud is dust-free. The 2008 campaign has revealed a transit by a filamentary, moderately-ionized cloud of variable density that is likely located in the BLR, and possibly part of a disk wind. Comment: Accepted for publication by A&A |
| Databáze: | arXiv |
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