Quasar absorption outflows on galactic scales: Insights from DESI

TL;DR

This study utilizes DESI spectral data to analyze five quasar outflows at intermediate redshifts, revealing their physical properties, energetics, and potential impact on galaxy evolution.

Contribution

It provides detailed characterization of low-ionization quasar outflows using DESI data, including their distances, energetics, and role in AGN feedback, which was previously limited.

Findings

Outflows are located 4.5 to 31 kpc from the AGN.

Kinetic luminosities are 2e-6 to 5e-3 of Eddington luminosity.

Outflows exhibit diverse ionization states and energetics.

Abstract

Absorption outflows in quasars play an important role in understanding active galactic nuclei (AGN) feedback and their influence on galaxy evolution. The unprecedented spectral data provided by the Dark Energy Spectroscopic Instrument (DESI) opens new avenues to explore these outflows. We analyze five low-ionization absorption outflow systems in four intermediate-redshift quasars ($2 < z < 3$) using the data obtained by DESI in order to characterize their physical properties and energetics, and also to assess their role in AGN feedback. We use the spectra from DESI's Early Data Release to determine the ionic column densities, total hydrogen column densities, electron number densities, and ionization parameters via photoionization modeling and absorption line analysis. We derive the outflows' distance from the AGN, and its kinematic properties: mass-flow rates, kinetic luminosity, and momentum flux. Our study identifies five distinct mini-broad absorption line outflow systems, hosted by four quasars. The identified outflows exhibit hydrogen column densities of $\log (N_H) = 20.0-20.7$[cm$^{-2}$], ionization parameters of $\log (U_H) = -2.7$ to $-2.1$, and electron number densities of $\log (n_e) =1.45-2.85$[cm$^{-2}$]. The distances of the outflows from the central source are between 4.5 to 31 kpc, and the kinetic luminosities range from $2\times10^{-6}$ to $5\times10^{-3}$ of the Eddington luminosity. The outflows in J1407 and J1032 show the largest kinetic luminosities, with momentum flux ratios ($\dot{p} / \dot{p}_{rad}$) of about 2 and 0.2, respectively. Our findings highlight the vital role of DESI data in uncovering the diversity and significance of quasar outflows in galaxy evolution.