This article from sciencealert states:
Astronomers think these two galactic cores could merge into one larger black hole, sending huge gravitational waves rippling out across spacetime. But if there's any asymmetry in the galactic merger, the newly forged black hole could be punted clean out of the galaxy and sent zooming across the Universe by gravitational wave recoil, taking a swarm of stars with it. Such runaway objects, theorised in the late noughties, are called hypercompact stellar systems (HCSSs) - a supermassive black hole with a tight bunch of gravitationally bound stars, careening away into the cosmos.
This article was written in 2020; now is the end of 2021. Have any HCSSs (supermassive black holes with a tight bunch of gravitationally bound stars) been detected since then?
What projects are currently actively searching for HCSSs?