Large-amplitude modulations and hours-timescale variability in the early X-ray light curve of a tidal disruption flare

We present new X-ray, optical, and UV observations of the tidal disruption event candidate , (hereafter Between 50 and 60 days after peak optical brightness, , exhibited large-amplitude modulations in its 0.2--2 keV emission, when the flux repeatedly dimed and re-brightened by a factor of ∼ , over a ∼3-day timescale. These modulations exhibited harder-when-brighter behaviour but were not detected in high-cadence observations obtained 60--70 days and 170--200 days after peak optical brightness, when the system instead exhibited stochastic X-ray variability over timescales of hours. We discuss the different physical mechanisms responsible for such exotic X-ray variability and explore the possibility that the modulations in were caused by the Lense-Thirring precession of the inner accretion flow around the disrupting black hole.