Physical characterization of the FeLoBAL outflow in SDSS J0932+0840: Analysis of VLT/UVES observations

¹ Department of Physics, Virginia Tech, Blacksburg, VA 24061, USA
² Department of Physics, Western Michigan University, 1120 Everett Tower, Kalamazoo, MI 49008-5252, USA
³ Department of Astronomy, University of Michigan, Ann Arbor, MI 48109, USA

^⋆ Corresponding author; mayanksh@vt.edu

Received: 24 October 2024
Accepted: 9 December 2024

Abstract

Context. The study of quasar outflows is essential for understanding the connection between active galactic nuclei (AGN) and their host galaxies. We analyzed the VLT/UVES spectrum of quasar SDSS J0932+0840 and identified several narrow and broad outflow components in absorption, with multiple ionization species including Fe II. This places it among the rare class of outflows known as iron low-ionization broad absorption line outflows (FeLoBALs).

Aims. We studied one of the outflow components to determine its physical characteristics by determining the total hydrogen column density, the ionization parameter, and the hydrogen number density. Through these parameters, we obtained the distance of the outflow from the central source, its mass outflow rate, and its kinetic luminosity, and we constrained the contribution of the outflow to the AGN feedback.

Methods. We obtained the ionic column densities from the absorption troughs in the spectrum and used photoionization modeling to extract the physical parameters of the outflow, including the total hydrogen column density and ionization parameter. The relative population of the observed excited states of Fe II was used to model the hydrogen number density of the outflow.

Results. We used the Fe II excited states to model the electron number density (n_e) and hydrogen number density (n_H) independently and obtained n_e ≃ 10^3.4 cm⁻³ and n_H ≃ 10^4.8 cm⁻³. Our analysis of the physical structure of the cloud shows that these two results are consistent with each other. This places the outflow system at a distance of 0.7_−0.4^+0.9 kpc from the central source, with a mass flow rate (Ṁ) of 43₋₂₆⁺⁶⁵ M_⊙ yr⁻¹ and a kinetic luminosity (Ė_k) of 0.7_−0.4^+1.1 × 10⁴³ erg s⁻¹. This is 0.5_−0.3^+0.7 × 10⁻⁴ of the Eddington luminosity (L_Edd) of the quasar, and we thus conclude that this outflow is not powerful enough to contribute significantly toward AGN feedback.