A variable-density absorption event in NGC 3227 mapped with Suzaku and Swift

Journal article

Publication Details

Author(s): Beuchert T, Markowitz A, Krauß F, Miniutti G, Longinotti AL, Guainazzi M, De La Calle Perez I, Malkan M, Elvis M, Miyaji T, Hiriart D, Lopez JM, Agudo I, Dauser T, Garcia J, Kreikenbohm A, Kadler M, Wilms J
Journal: Astronomy & Astrophysics
Publication year: 2015
Volume: 584
ISSN: 1432-0746


Context. 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.Aims. 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.Methods. We examine six Suzaku and 12 Swift observations from a 2008 campaign spanning five weeks. We use a model accounting for the complex spectral interplay of three absorbers with different levels of ionization. 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.Results. The 2008 absorption event is due to moderately-ionized (log xi similar to 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.Conclusions. 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.

FAU Authors / FAU Editors

Beuchert, Tobias
Dr.Karl-Remeis-Sternwarte Bamberg, Astronomisches Institut
Dauser, Thomas Dr.
Dr.Karl-Remeis-Sternwarte Bamberg, Astronomisches Institut
Krauß, Felicia
Dr.Karl-Remeis-Sternwarte Bamberg, Astronomisches Institut
Markowitz, Alex Dr.
Dr.Karl-Remeis-Sternwarte Bamberg, Astronomisches Institut
Wilms, Jörn Prof. Dr.
Professur für Astronomie und Astrophysik

External institutions with authors

European Space Astronomy Centre (ESAC)
Harvard University
Julius-Maximilians-Universität Würzburg
National Autonomous University of Mexico / Universidad Nacional Autónoma de México (UNAM)
Spanish National Research Council / Consejo Superior de Investigaciones Científicas (CSIC)
University of California Los Angeles (UCLA)
University of California, San Diego

How to cite

Beuchert, T., Markowitz, A., Krauß, F., Miniutti, G., Longinotti, A.L., Guainazzi, M.,... Wilms, J. (2015). A variable-density absorption event in NGC 3227 mapped with Suzaku and Swift. Astronomy & Astrophysics, 584. https://dx.doi.org/10.1051/0004-6361/201526790

Beuchert, Tobias, et al. "A variable-density absorption event in NGC 3227 mapped with Suzaku and Swift." Astronomy & Astrophysics 584 (2015).


Last updated on 2019-17-06 at 14:38