Role of Feedback in AGN-HOST Coevolution: A Study from Partially Obscured Active Galactic Nuclei

TL;DR

This study investigates how feedback from partially obscured AGNs influences the coevolution of supermassive black holes and their host galaxies, revealing links between accretion activity, outflows, and stellar population age.

Contribution

It introduces improved methods to analyze AGN spectra, confirming the connection between accretion rates, outflows, and host galaxy evolution in partially obscured AGNs.

Findings

Correlation between Eddington ratio and stellar age confirmed.

Outflows linked to accretion activity and star formation.

Partially obscured AGNs show younger hosts and higher accretion rates.

Abstract

Partially obscured AGNs within a redshift range $z=0.011\sim0.256$ are used to re-study the role of feedback in the AGN-host coevolution issue in terms of their [OIII]$\lambda$5007 emission line profile. The spectra of these objects enable us to determine the AGN's accretion properties directly from their broad H$\alpha$ emission. This is essential for getting rid of the "circular reasoning" in our previous study of narrow emission-line galaxies, in which the [OIII] emission line was used not only as a proxy of AGN's bolometric luminosity, but also as a diagnostic of outflow. In addition, the measurement of $D_n(4000)$ index is improved by removing an underlying AGN's continuum according to the corresponding broad H$\alpha$ emission. With these improvements, we confirm and reinforce the correlation between $L/L_{\mathrm{Edd}}$ and stellar population age. More important is that this correlation is found to be related to both [OIII] line blue asymmetry and bulk blueshift velocity, which suggests a linkage between SMBH growth and host star formation through the feedback process. The current sample of partially obscured AGNs shows that the composite galaxies have younger host stellar population, higher Eddington ratio, less significant [OIII] blue wing and smaller bulk [OIII] line shift than do the Seyfert galaxies .