Density calculations of NGC 3783 warm absorbers using a time-dependent photoionization model

TL;DR

This paper introduces a novel time-dependent photoionization model, tpho, to determine the density and distance of warm absorbers in NGC 3783, enhancing understanding of AGN outflows and their galactic impact.

Contribution

The study develops the tpho-delay method using a new time-dependent model to accurately estimate plasma density and outflow distance in AGN winds, accounting for non-equilibrium effects.

Findings

The tpho model effectively predicts delayed ionic states in warm absorbers.

Non-equilibrium effects are significant during the delayed phase of plasma ionization.

Future observations can improve constraints on outflow density and feedback energetics.

Abstract

Outflowing wind as one type of AGN feedback, which involves noncollimated ionized winds prevalent in Seyfert-1 AGNs, impacts their host galaxy by carrying kinetic energy outwards. However, the distance of the outflowing wind is poorly constrained due to a lack of direct imaging observations, which limits our understanding of their kinetic power and therefore makes the impact on the local galactic environment unclear. One potential approach involves a determination of the density of the ionized plasma, making it possible to derive the distance using the ionization parameter {\xi}, which can be measured based on the ionization state. Here, by applying a new time-dependent photoionization model, tpho, in SPEX, we define a new approach, the tpho-delay method, to calculate/predict a detectable density range for warm absorbers of NGC 3783. The tpho model solves self-consistently the time-dependent ionic concentrations, which enables us to study delayed states of the plasma in detail. We show that it is crucial to model the non-equilibrium effects accurately for the delayed phase, where the non-equilibrium and equilibrium models diverge significantly. Finally, we calculate the crossing time to consider the effect of the transverse motion of the outflow on the intrinsic luminosity variation. It is expected that future spectroscopic observations with more sensitive instruments will provide more accurate constraints on the outflow density, and thereby on the feedback energetics.