New Insights into Supermassive Black Hole Environments from AT 2022upj
Recent research has provided new insights into the environment surrounding supermassive black holes, particularly through the study of the tidal disruption event (TDE) and extreme coronal line emitter (ECLE) known as AT 2022upj. This event, identified at a redshift of z=0.054, exhibited unique spectral features that have implications for our understanding of black hole activity and the dynamics of their surrounding environments.
The study highlights that AT 2022upj is notable for being the second confirmed ECLE, and the first to show broad He II emission concurrently with a flare. This emission is a significant indicator of optical and ultraviolet TDEs. The researchers detected high-ionization lines such as [Fe X] and [Fe XIV] during the optical peak, marking the earliest observation of extreme coronal lines during an ongoing transient.
Additionally, X-ray emissions were observed during the optical transient phase, suggesting a potential link to the ionizing radiation responsible for the extreme coronal lines. The spectroscopic analysis revealed that the intensity of the [Fe X] and [Fe XIV] lines diminished within 400 days following the optical peak, while other lines, including [Fe VII] and [O III], began to emerge during the same timeframe.
The findings indicate that the velocities of the iron lines suggest the presence of circumnuclear gas within 0.1 parsecs of the central supermassive black hole. Furthermore, evidence of stratified material around the black hole was inferred from NEOWISE data, which indicated that circumnuclear dust is located at least 0.4 parsecs away. This research not only confirms the existence of complex interactions in the vicinity of supermassive black holes but also emphasizes the impact of high-energy flares, such as TDEs, on their environments.
The study, titled "Mapping the Inner 0.1 pc of a Supermassive Black Hole Environment with the Tidal Disruption Event and Extreme Coronal Line Emitter AT 2022upj," is available for further reading on arXiv: arXiv:2406.11972.