A Systematic Search for Active Galactic Nucleus Flares in ZTF Data Release 23

TL;DR

This paper presents a systematic search for AGN flares in six years of ZTF data, resulting in two catalogs of flares with potential astrophysical origins, and provides a publicly accessible resource for transient AGN phenomena.

Contribution

The authors developed a method to identify and catalog AGN flares in ZTF data, creating the first large-scale, publicly available AGN flare catalog with high-confidence events and potential astrophysical associations.

Findings

Identified 28,504 flares using Bayesian blocks and Gaussian Processes.

Created a refined catalog of 1,984 high-confidence AGN flares.

Some flares are linked to supernovae, tidal disruption events, or blazars.

Abstract

Active galactic nuclei (AGNs) are known to exhibit stochastic variability across a wide range of timescales and wavelengths. AGN flares are extreme outbursts that deviate from this typical behavior and may trace a range of energetic physical processes. Using six years of data from Zwicky Transient Facility (ZTF) Data Release 23, we conduct a systematic search for AGN flares among a sample of well-sampled AGNs and AGN candidates. We construct two catalogs: the AGN Flare Coarse Catalog (AGNFCC), containing 28,504 flares identified via Bayesian blocks and Gaussian Processes, and the AGN Flare Refined Catalog (AGNFRC), comprising 1,984 high-confidence flares selected using stricter criteria. We analyze their spatial distribution, temporal characteristics, host AGN type and potential origins. Some flares can be associated with known supernovae, tidal disruption events, or blazars, and a few may be linked to binary black hole mergers or microlensing events. These catalogs provide a valuable resource for studying transient phenomena in AGNs and are publicly available at https://github.com/Lyle0831/AGN-Flares.