The variable and non-variable X-ray absorbers in Compton-thin type-II Active Galactic Nuclei
| dc.contributor.author | Laha, Sibasish | |
| dc.contributor.author | Markowitz, Alex G. | |
| dc.contributor.author | Krumpe, Mirko | |
| dc.contributor.author | Nikutta, Robert | |
| dc.contributor.author | Rothschild, Richard | |
| dc.contributor.author | Saha, Tathagata | |
| dc.date.accessioned | 2020-06-09T16:29:37Z | |
| dc.date.available | 2020-06-09T16:29:37Z | |
| dc.date.issued | 2020-05-12 | |
| dc.description.abstract | We have conducted an extensive X-ray spectral variability study of a sample of 20 Compton-thin type II galaxies using broad band spectra from XMM-Newton, Chandra, and Suzaku. The aim is to study the variability of the neutral intrinsic X-ray obscuration along the line of sight and investigate the properties and location of the dominant component of the X-ray-obscuring gas. The observations are sensitive to absorption columns of NH∼10²⁰·⁵⁻²⁴cm⁻² of fully- and partially-covering neutral and/or lowly-ionized gas on timescales spanning days to well over a decade. We detected variability in the column density of the full-covering absorber in 7/20 sources, on timescales of months-years, indicating a component of compact-scale X-ray-obscuring gas lying along the line of sight of each of these objects. Our results imply that torus models incorporating clouds or overdense regions should account for line of sight column densities as low as ∼ a few ×10²¹ cm⁻². However, 13/20 sources yielded no detection of significant variability in the full-covering obscurer, with upper limits to ΔNH spanning 10²¹⁻²³ cm⁻². The dominant absorbing media in these systems could be distant, such as kpc-scale dusty structures associated with the host galaxy, or a homogeneous medium along the line of sight. Thus, we find that overall, strong variability in full-covering obscurers is not highly prevalent in Compton-thin type IIs, at least for our sample, in contrast to previous results in the literature. Finally, 11/20 sources required a partial-covering, obscuring component in all or some of their observations, consistent with clumpy near-Compton-thick compact-scale gas. | en_US |
| dc.description.sponsorship | : S.L. and A.G.M. acknowledge financial support from NASA via NASA-ADAP Award NNX15AE64G. S.L. and A.G.M. thank Matt Malkan for insightful discussions. A.G.M. and T.S. both acknowledge partial funding from Narodowy Centrum Nauki (NCN) grant 2016/23/B/ST9/03123. M.K. acknowledges support from DLR grants 50OR1802 and 50OR1904. The authors thank Johannes Buchner for assistance in setting up and running BXA and MultiNest. This research has made use of data obtained from the Chandra, XMM-Newton, and Suzaku missions by NASA, ESA and JAXA. This work has made use of HEASARC online services, supported by NASA/GSFC, and the NASA/IPAC Extragalactic Database, operated by JPL/California Institute of Technology under contract with NASA | en_US |
| dc.description.uri | https://arxiv.org/abs/2005.06079 | en_US |
| dc.format.extent | 56 pages | en_US |
| dc.genre | journal articles preprints | en_US |
| dc.identifier | doi:10.13016/m2aquq-hf1s | |
| dc.identifier.citation | Sibasish Laha et al., The variable and non-variable X-ray absorbers in Compton-thin type-II Active Galactic Nuclei, ApJ, https://arxiv.org/abs/2005.06079 | en_US |
| dc.identifier.uri | http://hdl.handle.net/11603/18847 | |
| dc.language.iso | en_US | en_US |
| dc.relation.isAvailableAt | The University of Maryland, Baltimore County (UMBC) | |
| dc.relation.ispartof | UMBC Center for Space Sciences and Technology | |
| dc.relation.ispartof | UMBC Faculty Collection | |
| dc.relation.ispartof | UMBC Physics Department | |
| dc.rights | This item is likely protected under Title 17 of the U.S. Copyright Law. Unless on a Creative Commons license, for uses protected by Copyright Law, contact the copyright holder or the author. | |
| dc.title | The variable and non-variable X-ray absorbers in Compton-thin type-II Active Galactic Nuclei | en_US |
| dc.type | Text | en_US |