Observations of Feedback from Radio-Quiet Quasars - II. Kinematics of Ionized Gas Nebulae

TL;DR

This study uses Gemini IFU observations to analyze ionized gas around radio-quiet quasars at z~0.5, revealing wide-angle outflows with high velocities and significant energetic impact on host galaxies.

Contribution

First detailed kinematic analysis of ionized gas nebulae around radio-quiet quasars at intermediate redshift, highlighting wide-angle outflows and their potential influence on galaxy evolution.

Findings

Nebulae exhibit large velocity widths up to 1000 km/s.

Outflows have median velocities around 760 km/s, comparable to escape velocities.

Kinetic energy flow and mass outflow rates are sufficient to affect host galaxy evolution.

Abstract

The prevalence and energetics of quasar feedback is a major unresolved problem in galaxy formation theory. In this paper, we present Gemini Integral Field Unit observations of ionized gas around eleven luminous, obscured, radio-quiet quasars at z~0.5 out to ~15 kpc from the quasar; specifically, we measure the kinematics and morphology of [O III]5007 emission. The round morphologies of the nebulae and the large line-of-sight velocity widths (with velocities containing 80% of the emission as high as 1000 km/s combined with relatively small velocity difference across them (from 90 to 520 km/s) point toward wide-angle quasi-spherical outflows. We use the observed velocity widths to estimate a median outflow velocity of 760 km/s, similar to or above the escape velocities from the host galaxies. The line-of-sight velocity dispersion declines slightly toward outer parts of the nebulae (by 3% per kpc on average). The majority of nebulae show blueshifted excesses in their line profiles across most of their extents, signifying gas outflows. For the median outflow velocity, we find a kinetic energy flow between 4x10^{44} and 3x10^{45} erg/s and mass outflow rate between 2000 and 20000 Msun/yr. These values are large enough for the observed quasar winds to have a significant impact on their host galaxies. The median rate of converting bolometric luminosity to kinetic energy of ionized gas clouds is ~2%. We report four new candidates for "super-bubbles" -- outflows that may have broken out of the denser regions of the host galaxy.