Unravelling the complex structure of AGN-driven outflows: I. Kinematics and sizes

TL;DR

This study uses integral field spectroscopy to analyze the kinematics and sizes of AGN-driven outflows in six local Type 2 AGNs, revealing smaller outflow sizes than previously estimated, which questions their role in galaxy feedback.

Contribution

First detailed kinematic analysis of AGN outflows in local Type 2 AGNs, providing more accurate size measurements and challenging previous overestimations.

Findings

Outflow sizes are between 1.3 and 2.1 kpc.

Previous methods likely overestimate outflow sizes by over a factor of 2.

Small outflow sizes cast doubt on their effectiveness for negative feedback.

Abstract

Outflows driven by active galactic nuclei (AGNs) are often invoked as agents of the long-sought AGN feedback. Yet, characterizing and quantifying the impact on their host galaxies has been challenging. We present Gemini Multi-Object Spectrograph integral field unit data of 6 local (z<0.1) and luminous (L$_{[OIII]}>10^{42}$ erg s$^{-1}$) Type 2 AGNs. In the first of a series of papers, we investigate the kinematics and constrain the size of the outflows. The ionized gas kinematics can be described as a superposition of a gravitational component that follows the stellar motion and an outflow-driven component that shows large velocity (up to 600 km s$^{-1}$) and large velocity dispersion (up to 800 km s$^{-1}$). Using the spatially resolved measurements of the gas, we kinematically measure the size of the outflow, which is found to be between 1.3 and 2.1 kpc. Due to the lack of a detailed kinematic analysis, previous outflow studies likely overestimate their size by up to more than a factor of 2, depending on how the size is estimated and whether the [OIII] or H$\alpha$ emission line is used. The relatively small size of the outflows for all 6 of our objects casts doubts on their potency as a mechanism for negative AGN feedback.