Spatially Resolved [O <scp>iii</scp>] Emission Line Kinematics of Reverberation-mapped Active Galactic Nuclei with the Keck Cosmic Web Imager

Abstract We present optical integral-field spectroscopic data of ten nearby (0.02 ≤ z ≤ 0.05) Seyfert 1 galaxies taken with the Keck Cosmic Web Imager. We map the spatially resolved kinematics of the [O iii ] gas and stars, and investigate the alignments between their global kinematic position angles (PAs). Large-scale gas motions are primarily dominated by rotation and are kinematically aligned with the stars (ΔPA ≤ 30°). However, eight galaxies exhibit nonrotational kinematic signatures (e.g., kinematic twists, possible outflows) in their ionized gas velocity fields near the nucleus. We compare aperture-wide measurements of the gas and stellar velocity dispersions ( σ gas and σ ⋆ ) to test the use of the width of the [O iii ] line core as a surrogate for σ ⋆ . Direct comparisons between σ gas and σ ⋆ show that σ gas tends to underestimate σ ⋆ , and thus is not a reliable tracer of σ ⋆ for our selected galaxies. We measure the extent of the narrow-line region (NLR) using several definitions, resulting in sizes of ∼0.1–10 kpc. For a given [O iii ] luminosity, our NLR sizes derived from the [O iii ]/H β flux ratio or an [O iii ] isophotal radius are an order of magnitude larger than those measured from past imaging data.