# Quantifying the AGN-driven outflows in ULIRGs (QUADROS) IV: HST/STIS spectroscopy of the sub-kpc warm outflow in F14394+5332

## TL;DR

This study uses HST/STIS spectroscopy to resolve and analyze the sub-kpc warm outflow in a ULIRG, revealing detailed kinematic and ionization properties crucial for understanding AGN feedback in galaxy evolution.

## Contribution

First high-resolution HST/STIS observations of a sub-kpc warm outflow in a ULIRG, providing detailed kinematic and ionization structure analysis.

## Key findings

- Outflow region is compact (~0.9 kpc) with high ionization.
- Outflow velocities increase from ~500 to 1800 km/s with radius.
- Outflow likely caused by acceleration and destruction of dense clouds in AGN-driven wind.

## Abstract

Considerable uncertainties remain about the nature of warm, AGN-driven outflows and their impact on the evolution of galaxies. This is because the outflows are often unresolved in ground-based observations. As part of a project to study the AGN outflows in some of the most rapidly evolving galaxies in the local Universe, here we present HST/STIS observations of F14394+5332E that resolve the sub-kpc warm outflow for the first time in a ULIRG. The observations reveal a compact, high-ionization outflow region (r_max~0.9 kpc) set in a more extensive (r_max~1.4 kpc) halo that is kinematically quiescent and has a lower ionization state. A large line width (600 < FWHM < 1500 km/s) is measured throughout the outflow region, and the outflowing gas shows a steep velocity gradient with radius, with the magnitude of the blueshifted velocities increasing from ~500 to 1800 km/s from the inner to the outer part of the outflow. We interpret the observations in terms of the local acceleration, and hydrodynamic destruction, of dense clouds as they are swept up in a hot, low density wind driven by the AGN. We discuss the implications for measuring the mass outflow rates and kinetic powers for the AGN-driven outflows in such objects.