2023ApJ...945...59L

We present a study of the relation between the [O III] 5007 Å emission line width (σ_[OIII]) and stellar velocity dispersion (σ_*), utilizing a sample of 740 type 1 active galactic nuclei (AGNs) with high-quality spectra at redshift z < 1.0. We find the broad correlation between the core component of the [O III] emission line width (${\sigma }_{[{\rm{O}}{\rm\small{III}},\mathrm{core}]}$) and σ_* with a scatter of 0.11 dex for the low redshift (z < 0.1) sample; for redshift (0.3 < z < 1.0) AGNs, the scatter is larger, being 0.16 dex. We also find that the Eddington ratio (L_bol/L_Edd) may play an important role in the discrepancies between ${\sigma }_{[{\rm{O}}{\rm\small{III}},\mathrm{core}]}$ and σ_*. As the L_bol/L_Edd increases, ${\sigma }_{[{\rm{O}}{\rm\small{III}},\mathrm{core}]}$ tends to be larger than σ_*. By classifying our local sample with different minor-to-major axis ratios, we find that σ_* is larger than ${\sigma }_{[{\rm{O}}{\rm\small{III}},\mathrm{core}]}$ for those edge-on spiral galaxies. In addition, we also find that the effects of outflow strength properties such as maximum outflow velocity (${V}_{\max }$) and the broader component of the [O III] emission line width and line shift (σ_[OIII,out] and V_[OIII,out]) may play a major role in the discrepancies between ${\sigma }_{[{\rm{O}}{\rm\small{III}},\mathrm{core}]}$ and σ_*. The discrepancies between ${\sigma }_{[{\rm{O}}{\rm\small{III}},\mathrm{core}]}$ and σ_* are larger when ${V}_{\max }$, V_[OIII,out], and σ_[OIII,out] increase. Our results show that the outflow strengths may have significant effects on the differences between narrow-line region gas and stellar kinematics in AGNs. We suggest that caution should be taken when using ${\sigma }_{[{\rm{O}}{\rm\small{III}},\mathrm{core}]}$ as a surrogate for σ_*. In addition, the substitute of ${\sigma }_{[{\rm{O}}{\rm\small{III}},\mathrm{core}]}$ for σ_* could be used only for low luminosity AGNs.