A failed wind candidate in NGC 3783 from the 2001 year campaign with Chandra/HETGS

TL;DR

This study reanalyzed Chandra observations of NGC 3783, revealing spectral variations in the warm absorber linked to continuum changes, suggesting the presence of a failed wind component within the galaxy.

Contribution

It provides the first detailed analysis of a low-ionization warm absorber component as a potential failed wind in NGC 3783, using time-dependent photoionization modeling.

Findings

Spectral variations in Fe UTA correlate with continuum flux increase.

Low-ionization component located within 0.27 pc of the nucleus.

Lower density limit of >10^{12.3} m^{-3} for the absorber.

Abstract

We reanalyze the Chandra/HETGS observations of NGC 3783 from the campaign in the year 2001, identifying significant spectral variations in the Fe unresolved transition array (UTA) over timescales of weeks to months. These changes correlate with a $1.4-2$ fold increase in the ionizing continuum and exceed $10 \, \sigma$ significance. The variations primarily originate from a low-ionization state ($\rm log \xi = 1.65$) component of the warm absorber. Time-dependent photoionization modelling confirms the sensitivity of this low-ionization component to continuum variations within the Fe UTA band. Local fitting indicates a lower density limit of $>10^{12.3} \, \rm m^{-3}$ at $3 \, \sigma$ statistical uncertainty, with the component located within $0.27 \, \rm pc$. Our findings suggest that this low-ionization component is a potential failed wind candidate.