A luminous X-ray outburst from an intermediate-mass black hole in an off-centre star cluster

Understand

A unique signature for the presence of massive black holes in very dense stellar regions is occasional giant-amplitude outbursts of multiwavelength radiation from tidal disruption and subsequent accretion of stars that make a close approach to the black holes.

• Previous strong tidal disruption event (TDE) candidates were all associated with the centers of largely isolated galaxies.
• Here we report the discovery of a luminous X-ray outburst from a massive star cluster at a projected distance of 12.5 kpc from the center of a large lenticular galaxy.
• The luminosity peaked at ~10^{43} erg/s and decayed systematically over 10 years, approximately following a trend that supports the identification of the event as a TDE.