Time Dependent Photoionization Modeling of Warm Absorbers: High-Resolution Spectra and Response to Flaring Light Curves

Abstract

Time dependent photoionization modeling of warm absorber outflows in active galactic nuclei can play an important role in understanding the interaction between warm absorbers and the central black hole. The warm absorber may be out of the equilibrium state because of the variable nature of the central continuum. In this paper, with the help of time dependent photoionization modeling, we study how the warm absorber gas changes with time and how it reacts to changing radiation fields. Incorporating a flaring incident light curve, we investigate the behavior of warm absorbers using a photoionization code that simultaneously and consistently solves the time dependent equations of level population, heating and cooling, and radiative transfer. We simulate the physical processes in the gas clouds, such as ionization, recombination, heating, cooling, and the transfer of ionizing radiation through the cloud. We show that time dependent radiative transfer is important and that calculations which omit this effect quantitatively and systematically underestimate the absorption. Such models provide crucial insights into the characteristics of warm absorbers and can constrain their density and spatial distribution.