# Supermassive black holes with high accretion rates in active galactic nuclei: X. Optical variability characteristics

## TL;DR

This study analyzes optical variability in 73 active galactic nuclei with a wide range of black hole masses and accretion rates, revealing correlations that suggest a common underlying physical mechanism across different accretion regimes.

## Contribution

It systematically investigates the optical variability characteristics of AGNs with diverse properties using the DRW model and MCMC, including super-Eddington accreting black holes, which is novel.

## Key findings

- Variability correlates with black hole mass, accretion rate, and luminosity.
- Correlations are smooth across sub- and super-Eddington regimes.
- Variability may be driven by a common physical process.

## Abstract

We compiled a sample of 73 active galactic nuclei (AGNs) with reverberation mapping (RM) observations from RM campaigns including our ongoing campaign of monitoring super-Eddington accreting massive black holes (SEAMBHs). This sample covers a large range of black hole (BH) mass $(M_{\bullet}=10^{6-9}~M_\odot)$, dimensionless accretion rates $(\dot{\mathscr{M}}=10^{-2.7}-10^{2.7})$ and 5100~\AA~luminosity $(L_{5100}=10^{42-46}~\rm erg~s^{-1})$, allowing us to systematically study the AGN variability and their relations with BH mass, accretion rates, and optical luminosity. We employed the damped random walk (DRW) model to delineate the optical variability of continuum at 5100~\AA~and obtained damped variability timescale ($\tau_{\rm d}$) and amplitude ($\sigma_{\rm d}$) using a Markov Chain Monte Carlo (MCMC) method. We also estimated the traditional variability amplitudes ($F_{\rm var}$), which provide a model-independent measure and therefore are used to test the DRW results. We found that AGN variability characteristics are generally correlated with $(M_{\bullet},\dot{\mathscr{M}},L_{5100})$. These correlations are smooth from sub-Eddington to super-Eddington accretion AGNs, probably implying that the AGN variability may be caused by the same physical mechanism.