A Remarkably Loud Quasi-Periodicity after a Star is Disrupted by a Massive Black Hole

TL;DR

This paper reports the discovery of a stable 131-second x-ray quasi-periodicity following a star's disruption by a black hole, providing insights into the black hole's properties and spin.

Contribution

It presents the first detection of a long-lasting, stable quasi-periodic signal after a tidal disruption event, revealing details about the black hole's spin and proximity to the event horizon.

Findings

The periodicity originates close to the black hole's event horizon.

The black hole is inferred to be rapidly spinning.

Such quasi-periodicities can encode black hole properties.

Abstract

The immense tidal forces of massive black holes can rip apart stars that come too close to them. As the resulting stellar debris spirals inwards, it heats up and emits x-rays when near the black hole. Here, we report the discovery of an exceptionally stable 131-second x-ray quasi-periodicity from a black hole after it disrupted a star. Using a black hole mass indicated from host galaxy scaling relations implies that, (1) this periodicity originates from very close to the black hole's event horizon, and (2) the black hole is rapidly spinning. Our findings suggest that other disruption events with similar highly sensitive observations likely also exhibit quasi-periodicities that encode information about the fundamental properties of their black holes.