References of "Dovčiak, M"
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See detailEclipsing the innermost accretion disc regions in AGN
Sanfrutos, M.; Miniutti, G.; Dovčiak, M. et al

in Astronomische Nachrichten (2016), 337

Variable X-ray absorption has been observed in active galactic nuclei (AGN) on several time scales. Observations allow us to identify the absorber with clouds associated either with the clumpy torus ... [more ▼]

Variable X-ray absorption has been observed in active galactic nuclei (AGN) on several time scales. Observations allow us to identify the absorber with clouds associated either with the clumpy torus (parsec scales, long timescales) or with the broad line region (BLR) (short timescales). In the latter, the cloud size has been estimated to be of the order of few gravitational radii from the observed absorption variability. Such small cloud sizes are comparable to the X-ray emitting regions so that a detailed modeling of occultation events in AGN has the potential of enabling us to infer accurately the geometry of the system. We have developed a relativistic X-ray spectral model for occultation events and we present here theoretical predictions on the different observables that can be inferred by studying X-ray eclipses in simulated XMM-Newton data. These include the size of the X-ray emitting regions as well as more fundamental parameters such as the black hole spin and the system inclination. We find that absorption varies as a function of the energy range and that its maximum takes place when the approaching part of the accretion disc is covered. Therefore we study the hard-to-soft (H / S) ratio light curves produced during an eclipse and use them to characterise the properties of the inner accretion disc in a new model-independent way. [less ▲]

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See detailAthena+: The first Deep Universe X-ray Observatory
Barret, D.; Nandra, K.; Barcons, X. et al

in Cambresy, L.; Martins, F.; Nuss, E. (Eds.) et al SF2A-2013: Proceedings of the Annual meeting of the French Society of Astronomy and Astrophysics (2013, November 01)

The Advanced Telescope for High-energy Astrophysics (Athena+) is being proposed to ESA as the L2 mission (for a launch in 2028) and is specifically designed to answer two of the most pressing questions ... [more ▼]

The Advanced Telescope for High-energy Astrophysics (Athena+) is being proposed to ESA as the L2 mission (for a launch in 2028) and is specifically designed to answer two of the most pressing questions for astrophysics in the forthcoming decade: How did ordinary matter assemble into the large scale structures we see today? and how do black holes grow and shape the Universe? For addressing these two issues, Athena+ will provide transformational capabilities in terms of angular resolution, effective area, spectral resolution, grasp, that will make it the most powerful X-ray observatory ever flown. Such an observatory, when opened to the astronomical community, will be used for virtually all classes of astrophysical objects, from high-z gamma-ray bursts to the closest planets in our solar neighborhood. In this paper, we briefly review the core science objectives of Athena+, present the science requirements and the foreseen implementation of the mission, and illustrate its transformational capabilities compared to existing facilities. [less ▲]

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