Fast Outflowing Warm Absorbers in Narrow-Line Seyfert 1 Galaxy PG 1001+054 Revealed by HST/COS Spectra

TL;DR

This paper reports the discovery of high-velocity warm absorbers in the NLS1 galaxy PG 1001+054, revealing a multiphase outflow that could significantly impact the host galaxy through AGN feedback.

Contribution

It presents the first detection of fast outflowing warm absorbers in a NLS1 galaxy and models their physical properties and potential influence on galaxy evolution.

Findings

Detected outflow velocities of 7000-9000 km/s.

Estimated absorber locations from 1 to 73 parsecs.

Outflow kinetic power could reach 1.7% of Eddington luminosity.

Abstract

Narrow-Line Seyfert 1 (NLS1) Galaxies are an important type of active galactic nucleus (AGN), generally expected to be accreting at high Eddington rate. The properties of their outflows and importance of AGN feedback remain intriguing. We report on the discovery of fast outflowing warm absorbers (WAs) in the NLS1 PG 1001+054, with velocities in the range of 7000 to 9000 kilometers per second. They are identified with blueshifted Lyman alpha, N v and Si iv lines in the high resolution ultraviolet (UV) spectra taken with the Cosmic Origins Spectrograph (COS) onboard the Hubble Space Telescope (HST). We perform photoionization modeling using XSTAR with three WAs. The derived physical properties are typical of WAs in terms of ionization and column density, whereas the outflow velocities are significantly higher. The estimated location of these WAs ranges from 1 to 73 parsecs away from the AGN. Together with previous detection of high ionization absorber in the X-ray for PG 1001+054, we suggest that the fast outflowing UV absorber is probably a part of a multiphase outflow. Such structure is likely produced by the outflow launched from AGN at accretion disk scale, which shocks the ambient ISM producing stratified absorbers. Assuming contribution from the three WAs at tens of parsecs, the estimated ratio between the kinetic power of the outflow and AGN Eddington luminosity could reach 1.7 percent, raising the possibility of sufficient influence on the host galaxy when compared to some theoretical models for efficient AGN feedback.