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

Abstract

To investigate 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 the [O III] luminosity >10 41.5 erg s −1 , and 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 [O III] and Hα lines, respectively. The broad components in both [O III] and Hα represent the non-gravitational kinematics, i.e., gas outflows, while the narrow components, especially in Hα, represent the gravitational kinematics, i.e., 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 1.0-38.5×105 M , 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 0.02±0.01 M 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)×L bol /c on average, except for two most kinematically energetic AGNs with low L bol , 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.

Outflow Kinematics Manifested by the Hα Line: Gas Outflows in Type 2 AGNs. IV.

“…The difference is noticeable in the case of composite objects as expected since the contribution from non-AGN, i.e., SF region, is most significant compared to Seyfert galaxies and LINERs. While the limitation of this work is the lack of spatial resolution, Karouzos et al (2016); Bae et al (2017) used a subsample of AGNs with strong outflow signatures in [O iii] to obtain integral field spectroscopy data. By applying the same kinematic analysis with double Gaussian models adopted in this paper to each pixel in the outflow region, they found that both narrow and broad components of [O iii] are presenting non-viral outflow kinematics.…”

Ionized-gas Kinematics Along the Large-scale Radio Jets in Type-2 AGNs

“…Green-dots present the results from Karouzos et al (2016a). The measured values from Bae et al (2017) Husemann et al (2014) and Bae et al (2017) . ized gas emissions are aligned, the radio jets may be responsible for driving outflows and shock ionization, hence driving the correlations between radio emissions and gas kinematics (e.g., Veilleux 1991;Bower et al 1995;Zakamska & Greene 2014). In a radio-loud AGN 4C12.50 fast outflows in HI gas are detected with an extremely blue-shifted velocity, ∼1000 km s −1 relative to the systematic velocity at the location of the southern jet.…”

“…In Figure 8 we compare the measured NLR size based on [O III] with the [O III] luminosity for our sample, combined with various AGNs selected from literature, for which the photoionization size was measured with a consistent manner (Husemann et al 2013(Husemann et al , 2014Karouzos et al 2016a;Bae et al 2017). Note that since all these measures are dust-uncorrected [O III] luminosity, we use [O III] luminosity without correcting for dust obscuration.…”

“…However, the extent of the photoionization region is different from that of gas outflows, since gas can be ionized by the central source while the kinematics of the ionized gas can simply follow the gravitational potential of the host galaxy without showing any outflows. Therefore, Karouzos et al (2016a) and Bae et al (2017) measured the size of the outflows based on the [O III] kinematics compared to stellar kinematics, instead of measuring the extent of the photoionization region. A detailed comparison between the photoionization and outflow sizes will be presented in the future (Kang et al 2017 in preparation).…”

“…The photoionization size (R NLR ) can be probed based on the spatial distribution of ionized gas, which is manifested by the surface brightness distribution in the narrow band images with the [O III] filter or by the spatial distribution of [O III] emission in long-slit or integral field spectroscopy (e.g. Bennert et al 2006a,b;Husemann et al 2013;Oh et al 2013;Karouzos et al 2016a;Bae et al 2017). We check the [O III]/Hβ ratio as a function of radius, confirming that the ionizing source is the central AGN in each object.…”