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 H α lines, respectively. The broad components in both [O iii ] and H α represent the nongravitational kinematics, that is, gas outflows, while the narrow components, especially in H α , 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.