Seoul National University AGN Monitoring Project. V. Velocity-resolved H-beta Reverberation Mapping and Evidence of Kinematics Evolution

TL;DR

This study presents velocity-resolved H-beta reverberation mapping for 20 AGNs, revealing diverse BLR kinematics and evidence of evolution over time, expanding understanding across a broad luminosity range.

Contribution

It provides the largest high-luminosity velocity-resolved reverberation mapping sample, identifying common kinematic structures and their evolution in AGN broad-line regions.

Findings

Symmetric velocity-resolved lags are most common (40%).

Inflow kinematics occur in 20% of cases.

Evidence of BLR kinematics evolution in two AGNs.

Abstract

We present velocity-resolved reverberation lags of H-beta for 20 active galactic nuclei (AGNs) from the Seoul National University AGN Monitoring Project. We detect unambiguous velocity-resolved structures in 12 AGNs, among which eight objects exhibit symmetric structures, two objects show inflow-like characteristics, and two objects display outflow-like signatures. For two AGNs, we successfully measure the velocity-resolved lags in different years, revealing evidence of evolving broad-line region (BLR) kinematics. By combining our sample with the literature velocity-resolved lags, we find that the symmetric velocity-resolved lags are the most common (40%) type among this sample. The frequency of inflow kinematics is also notable (20%), while outflow kinematics are less common (11%). Our sample significantly expands the previous velocity-resolved reverberation mapping sample in the high-luminosity regime, enabling us to constrain BLR kinematics across a large dynamic range of luminosity.