ﻻ يوجد ملخص باللغة العربية
With the advent of the present and future spatial X-ray missions, it becomes crucial to model correctly the line spectrum of X-ray emitting media. We have built a photoionization code, Titan, solving the transfer of a thousand lines and of the continuum with the Accelerated Lambda Iteration method, which is most reliable for line transfer. In all other photoionization codes the line intensities are computed with the so-called escape probability formalism, used in its simplest approximation. In a previous paper (Dumont et al. 2003), it was shown that this approximation leads to errors which can exceed one order of magnitude in the case a Thomson thickness of the order of unity. We show here that it also happens in the case of a Thomson thickness of 0.001 to 0.1. The errors on the line fluxes and line ratios are of the order of 30% for a column density of 10^{20} cm^{-2}, and a factor five for a column density of 10^{23} cm^{-2}, in conditions appropriate for Seyfert 2 and for the Warm Absorber of Seyfert 1.
We present a new version of the fully 3D photoionization and dust radiative transfer code, MOCASSIN, that uses a Monte Carlo approach for the transfer of radiation. The X-ray enabled MOCASSIN allows a fully geometry independent description of low-den
A two-dimensional hydrodynamics code for Type Ia supernovae (SNIa) simulations is presented. The code includes a fifth-order shock-capturing scheme WENO, detailed nuclear reaction network, flame-capturing scheme and sub-grid turbulence. For post-proc
Using the new version of the photoionization code Titan designed for plane-parallel photoionized thick hot media, which is unprecedented from the point of view of line transfer, we have undertaken a study of the influence of different parameters on t
Current X-ray observations and simulations show that gravitational lensing can be used to infer the structure near the event horizons of black holes, constrain the dynamics and evolution of black-hole accretion and outflows, test general relativity i
We report on the detection of a remarkable new fast high-energy transient found in the Chandra Deep Field-South, robustly associated with a faint ($m_{rm R}=27.5$ mag, $z_{rm ph}$$sim$2.2) host in the CANDELS survey. The X-ray event is comprised of 1