Time-dependent photoionization spectroscopy of the Seyfert galaxy NGC 3783

TL;DR

This study uses time-dependent photoionization models to analyze the warm absorbers in Seyfert galaxy NGC 3783, revealing broader charge state distributions and improved spectral fits, with implications for AGN feedback.

Contribution

It introduces a time-evolving photoionization model in SPEX that better captures the spectral properties of AGN absorbers compared to equilibrium models.

Findings

Time-evolving models produce broader charge state distributions.

Inclusion of variability improves spectral fits.

Absorbers are likely expelled at escape velocities.

Abstract

We present an investigation into the spectroscopic properties of non-equilibrium photoionization processes operating in a time-evolving mode. Through a quantitative comparison between equilibrium and time-evolving models, we find that the time-evolving model exhibits a broader distribution of charge states compared to the equilibrium model, accompanied by a slight shift in the peak ionization state depending on the source variability and gas density. The time-evolving code, tpho in SPEX, has been successfully employed to analyze the spectral properties of warm absorbers in the Seyfert galaxy NGC 3783. The incorporation of variability in the tpho model improves the fits of the time-integrated spectra, providing more accurate descriptions to the average charge states of several elements, in particular for Fe which is peaked around Fe XIX. The inferred densities and distances of the relevant X-ray absorber components are estimated to be approximately a few 1E11 per cubic meter and less than 1 pc, respectively. Furthermore, the updated fit suggests a potential scenario in which the observed absorbers are being expelled from the central AGN at the escape velocities. This implies that these absorbers might not play a significant role in the AGN feedback mechanism.