The Close AGN Reference Survey (CARS): Mrk 1018 halts dimming and experiences strong short-term variability

TL;DR

This study monitors the changing brightness of AGN Mrk 1018, revealing it halted its dimming, experienced a short-term outburst, and continues to show variability, highlighting complex accretion and emission processes.

Contribution

It provides detailed, ongoing multiwavelength observations of Mrk 1018's recent variability and outburst behavior, offering new insights into AGN state changes and broad-line region dynamics.

Findings

AGN Mrk 1018 halted dimming and rebrightened

Observed inhomogeneous broad-line region with red wing asymmetry

AGN brightness remains variable, indicating ongoing activity

Abstract

After changing optical AGN type from 1.9 to 1 in 1984, the AGN Mrk 1018 recently reverted back to its type 1.9 state. Our ongoing monitoring now reveals that the AGN has halted its dramatic dimming, reaching a minimum around October 2016. The minimum was followed by an outburst rising with $\sim$0.25 U-band mag/month. The rebrightening lasted at least until February 2017, as confirmed by joint Chandra and Hubble observations. Monitoring was resumed in July 2017 after the source emerged from sunblock, at which point the AGN was found only $\sim$0.4 mag brighter than its minimum. The intermittent outburst was accompanied by the appearance of a red wing asymmetry in broad-line shape, indicative of an inhomogeneous broad-line region. The current flickering brightness of Mrk 1018 following its rapid fading either suggests that the source has reignited, remains variable at a low level, or may continue dimming over the next few years. Distinguishing between these possibilities requires continuous multiwavelength monitoring.