Investigating the {Origin} of the Absorption-Line Variability in Narrow-Line Seyfert 1 Galaxy WPVS 007

TL;DR

This study uses spectral synthesis modeling to analyze the short-term absorption-line variability in WPVS 007, revealing that changes in the outflow's covering fraction drive the observed spectral changes.

Contribution

First application of SimBAL to multiple epochs showing the utility of time-domain data in spectral modeling of AGN outflows.

Findings

WPVS 007 has a highly ionized outflow with significant mass-loss.

Absorption-line variability is primarily due to changes in the outflow's covering fraction.

Demonstrates SimBAL's capability to incorporate multi-epoch data for spectral analysis.

Abstract

Broad Absorption Line Quasars (BALQs) are actively accreting supermassive black holes that have strong outflows characterized by broad absorption lines in their rest-UV spectra. Variability in these absorption lines occurs over months to years depending on the source. WPVS 007, a low-redshift, low-luminosity Narrow-line Seyfert 1 (NLS1) shows strong variability over shorter timescales, providing a unique opportunity to study the driving mechanism behind this variability that may mimic longer scale variability in much more massive quasars. We present the first variability study using {the} spectral synthesis code SimBAL, which provides velocity-resolved changes in physical conditions of the gas using constraints from multiple absorption lines. Overall, we find WPVS 007 to have a highly ionized outflow with a large mass-loss rate and kinetic luminosity. We determine the primary cause of the absorption-line variability in WPVS 007 to be a change in covering fraction of the continuum by the outflow. This study is the first SimBAL analysis where multiple epochs of observation were fit simultaneously, demonstrating the ability of SimBAL to use the time-domain as an additional constraint in spectral models.