Galactic Scale Absorption Outflow in the Low Luminosity Quasar IRAS~F04250-5718: HST/COS Observations

TL;DR

This study analyzes the outflow in the low luminosity quasar IRAS F04250-5718 using HST/COS ultraviolet spectra, revealing multiple ionization components and suggesting the outflow may be part of a galactic wind at a distance greater than 3 kpc from the nucleus.

Contribution

First detailed absorption line analysis of IRAS F04250-5718's outflow, identifying multiple ionization states and estimating its large distance from the central source.

Findings

Identified three kinematic components with velocities from -50 to -230 km/s.

Determined the electron density in the main component is less than 30 cm^-3.

Estimated the outflow's distance from the nucleus to be over 3 kpc.

Abstract

We present absorption line analysis of the outflow in the quasar IRAS F04250-5718. Far-ultraviolet data from the Cosmic Origins Spectrograph onboard the Hubble Space Telescope reveal intrinsic narrow absorption lines from high ionization ions (e.g., C IV, N V, and O VI) as well as low ionization ions (e.g., C II and Si III). We identify three kinematic components with central velocities ranging from ~-50 to ~-230 km/s. Velocity dependent, non-black saturation is evident from the line profiles of the high ionization ions. From the non-detection of absorption from a metastable level of C II, we are able to determine that the electron number density in the main component of the outflow is < 30 per cubic cm. Photoionization analysis yields an ionization parameter log U ~ -1.6 +/- 0.2, which accounts for changes in the metallicity of the outflow and the shape of the incident spectrum. We also consider solutions with two ionization parameters. If the ionization structure of the outflow is due to photoionization by the active galactic nucleus, we determine that the distance to this component from the central source is > 3 kpc. Due to the large distance determined for the main kinematic component, we discuss the possibility that this outflow is part of a galactic wind.