Ms. Shalini Ganguly

The interaction between radiation from the center of an active galactic nucleus (AGN) and its surrounding matter drives outflows at parsec scales from the central engine. The so-called warm absorbers (X-ray absorbers) trace these ionized outflows and have been observed in more than half of all nearby AGNs. It has been found that these thermally driven outflow solutions are unsteady and can even form dense clumps due to thermal instability. To better understand their observational consequences, we compute absorption line profiles using our outflow solutions. We incorporate photoionization calculations into our hydrodynamic simulations in order to study the line profiles for a wide range of ions that help display the ionization stratification in these outflows. Although our calculations are based on 1D radial outflow mod-els, we find that each model produces diverse profiles and some profiles are quite complex, especially for clumpy models. Clumpy outflow solutions have absorption troughs with their maximum blueshifts in agreement with the maximum flow velocity. In addition to this, we find that clumpy solutions can imprint distinguishable absorption troughs at widely separated velocities. Future X-ray observatories such as XRISM and ATHENA should allow us to verify these characterizing clump-like features. Thus, we conclude that our models serve as viable models for warm absorbers. Currently, our ongoing efforts at refining the models constitute studying the effect of additional physics such as thermal conduction and improving our line profiles by assuming a Lorentzian profile.