Recently, a hard X-ray transient event-Sw J1644+57, was discovered by the Swift satellite, which marks the onset of a relative jet from a supermassive black hole, which was triggered by a tidal disruption event (TDE).
Another candidate in the same category Sw J2058 05 was also given. The small number of cases shows that run only a small fraction of relativistic jets TDES. A general prediction is that these rare events have to do to rapidly rotating black holes.
We realize begins Jet Blandford-Znajek mechanism, and limit the available data on the parameters turn black hole for both events. It turns out that two black holes, in fact, carry a moderate to high spin, suggesting that the spin of the black hole is probably the decisive factor for the J1644 +57- Sw such events.