The Limited Impact of Outflows: Integral-field Spectroscopy of 20 Local AGNs

Abstract

To investigate active galactic nucleus (AGN) outflows as a tracer of AGN feedback on star formation, we perform integral-field spectroscopy of 20 type 2 AGNs at z < 0.1, which are luminous AGNs with [O iii] luminosity > 10 erg s⁻¹ that exhibit strong outflow signatures in the [O iii] kinematics. By decomposing the emission-line profile, we obtain the maps of the narrow and broad components of the [O iii] and Hα lines, respectively. The broad components in both [O iii] and Hα represent the nongravitational kinematics, that is, gas outflows, while the narrow components, especially in Hα, represent the gravitational kinematics, that is, the rotational disk. By using the integrated spectra within the flux-weighted size of the narrow-line region, we estimate the energetics of the gas outflows. The ionized gas mass is 1.0–38.5, and the mean mass outflow rate is 4.6 ± 4.3 M _⊙ yr⁻¹, which is a factor of ~260 higher than the mean mass accretion rate of 0.02 ± 0.01 yr⁻¹. The mean energy injection rate of the sample is 0.8% ± 0.6% of the AGN bolometric luminosity , while the momentum flux is (5.4 ± 3.6) × on average, except for the two most kinematically energetic AGNs with low , which are possibly due to the dynamical timescale of the outflows. The estimated outflow energetics are consistent with the theoretical expectations for energy-conserving outflows from AGNs, yet we find no supporting evidence of instantaneous quenching of star formation due to the outflows.