The Tidal Disruption Event AT2021ehb: Evidence of Relativistic Disk Reflection, and Rapid Evolution of the Disk-Corona System

Understand

We present X-ray, UV, optical, and radio observations of the nearby ($\approx78$ Mpc) tidal disruption event (TDE) AT2021ehb/ZTF21aanxhjv during its first 430 days of evolution.

• AT2021ehb occurs in the nucleus of a galaxy hosting a $\approx 10^{7}\,M_\odot$ black hole ($M_{\rm BH}$ inferred from host galaxy scaling relations).
• High-cadence Swift and NICER monitoring reveals a delayed X-ray brightening.
• The spectrum first undergoes a gradual ${\rm soft }\rightarrow{\rm hard}$ transition and then suddenly turns soft again within 3 days at $\delta t\approx 272$ days during which the X-ray flux drops by a factor of ten.