4 results on '"Stalevski, Marko"'
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2. X-ray radiative transfer in full 3D with SKIRT
- Author
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Vander Meulen, Bert, Camps, Peter, Stalevski, Marko, and Baes, Maarten
- Subjects
High Energy Astrophysical Phenomena (astro-ph.HE) ,Physics and Astronomy ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,FOS: Physical sciences ,Astronomy and Astrophysics ,Astrophysics - High Energy Astrophysical Phenomena ,Astrophysics - Astrophysics of Galaxies - Abstract
Models of active galactic nuclei (AGN) suggest that their circumnuclear media are complex with clumps and filaments, while recent observations hint towards polar extended structures of gas and dust, as opposed to the classical torus paradigm. The X-ray band forms an interesting window to study these circumnuclear media in great detail. In this work, we extended the radiative transfer code SKIRT with the X-ray processes that govern the broadband X-ray spectra of obscured AGN, to study the structure of AGN circumnuclear media in full 3D, based on their reflected X-ray emission. We extended the SKIRT code with Compton scattering on free electrons, photo-absorption and fluorescence by cold atomic gas, scattering on bound electrons, and extinction by dust. This includes a novel treatment of extreme-forward scattering by dust, and a detailed description of anomalous Rayleigh scattering. To verify our X-ray implementation, we performed the first dedicated benchmark of X-ray torus models, comparing five X-ray radiative transfer codes. Finally, we illustrated the 3D nature of the code by producing synthetic X-ray images and spectra of clumpy torus models. SKIRT forms a powerful new tool to model AGN circumnuclear media in full 3D from X-ray to millimetre wavelengths, and is now publicly available. In the X-ray regime, we find an excellent agreement with the simulation results of the MYTorus and RefleX codes, which validates our X-ray implementation. We find some discrepancies with other codes, which motivates the need for a robust framework that can handle non-linear 3D radiative transfer effects. The new X-ray functionalities of the SKIRT code allow for uncomplicated access to a broad suite of 3D X-ray models for AGN that can easily be tested and modified. This will be particularly useful with the advent of X-ray microcalorimeter observations., 20 pages, 20 figures, accepted for publication in Astronomy & Astrophysics
- Published
- 2023
- Full Text
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3. Spatial field reconstruction with INLA
- Author
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Smole, Majda, primary, Rino-Silvestre, João, additional, González-Gaitán, Santiago, additional, and Stalevski, Marko, additional
- Published
- 2023
- Full Text
- View/download PDF
4. Polar dust obscuration in broad-line active galaxies from the XMM-XXL field
- Author
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Aix-Marseille Université, Agencia Estatal de Investigación (España), Ministerio de Ciencia, Innovación y Universidades (España), Ministry of Education, Science and Technological Development (Serbia), Republic of Serbia, Buat, Véronique, Mountrichas, George, Yang, Guang, Boquien, Médéric, Roehlly, Y., Burgarella, Denis, Stalevski, Marko, Ciesla, Laure, Theulé, Patrice, Aix-Marseille Université, Agencia Estatal de Investigación (España), Ministerio de Ciencia, Innovación y Universidades (España), Ministry of Education, Science and Technological Development (Serbia), Republic of Serbia, Buat, Véronique, Mountrichas, George, Yang, Guang, Boquien, Médéric, Roehlly, Y., Burgarella, Denis, Stalevski, Marko, Ciesla, Laure, and Theulé, Patrice
- Abstract
[Aims]: Dust is observed in the polar regions of nearby active galactic nuclei (AGN) and it is known to contribute substantially to their mid-IR emission and to the obscuration of their UV to optical emission. We aim to carry out a statistical test to check whether this component is a common feature based on an analysis of the integrated spectral energy distributions of these composite sources., [Methods]: We selected a sample of 1275 broad-line AGN in the XMM-XXL field, with optical to infrared photometric data. These AGN are seen along their polar direction and we expect a maximal impact of dust located around the poles when it is present. We used X-CIGALE, which introduces a dust component to account for obscuration along the polar directions, modeled as a foreground screen, and an extinction curve that is chosen as it steepens significantly at short wavelengths or is much grayer. By comparing the results of different fits, we are able to define subsamples of sources with positive statistical evidence in favor of or against polar obscuration (if present) and described using the gray or steep extinction curve., [Results]: We find a similar fraction of sources with positive evidence for and against polar dust. Applying statistical corrections, we estimate that half of our sample could contain polar dust and among them, 60% exhibit a steep extinction curve and 40% a flat extinction curve; although these latter percentages are found to depend on the adopted extinction curves. The obscuration in the V-band is not found to correlate with the X-ray column density, while AV/NH ratios span a large range of values and higher dust temperatures are found with the flat, rather than with the steep extinction curve. Ignoring this polar dust component in the fit of the spectral energy distribution of these composite systems leads to an overestimation of the stellar contribution. A single fit with a polar dust component described with an SMC extinction curve efficiently overcomes this issue but it fails at identifying all the AGN with polar dust obscuration.
- Published
- 2021
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