Lense-Thirring precession after a supermassive black hole disrupts a star

This paper reports the discovery of strong, quasi-periodic X-ray flux and temperature modulations in a tidal disruption event (TDE), AT2020ocn/ZTF18aakelin. These modulations, separated by roughly 15 days and lasting about 130 days, are consistent with Lense-Thirring precession of the accretion flow. While other mechanisms cannot be ruled out, the authors constrain the black hole's dimensionless spin parameter (a) to be between 0.05 and 0.5, assuming typical TDE parameters and rigid body precession of the disk.

Dheeraj R. Pasham, Michal Zajaček, C. J. Nixon, Eric R. Coughlin, Marzena Śniegowska, Agnieszka Janiuk, Bożena Czerny, Thomas Wevers, Muryel Guolo, Yukta Ajay, Michael Loewenstein