2016MNRAS.463L..99S

HLX-1, currently the best intermediate-mass black hole candidate, has undergone seven violent outbursts, each with a peak X-ray luminosity of L_peak,X ∼ 10⁴² erg s^–1. Interestingly, the properties of the HLX-1 outbursts evolve with time. In this work, we aim to constrain the physical parameters of the central engine of the HLX-1 outbursts in the framework of the black hole accretion. We find that the physical properties of the HLX-1 outbursts are consistent with being driven by the radiation pressure instability. This scenario can explain the evolution of the recurrent time-scales of the HLX-1 outbursts as a function of the durations.