Free Astronomy Magazine May-June 2020

29 MAY-JUNE 2020 SPACE CHRONICLES inside a dense star cluster. Interme- diate-mass black holes (IMBHs) are a long-sought “missing link” in black hole evolution. There have been a few other IMBH candidates found to date. They are smaller than the supermassive black holes that lie at the cores of large galaxies, but larger than stellar-mass black holes formed by the collapse of massive stars. This new black hole is over 50,000 times the mass of our Sun. IMBHs are hard to find. “Intermedi- ate-mass black holes are very elu- sive objects, and so it is critical to carefully consider and rule out alter- native explanations for each candi- date. That is what Hubble has allowed us to do for our candidate,” said Dacheng Lin of the University T his artist’s impression depicts a star being torn apart by an in- termediate-mass black hole (IMBH), surrounded by an accretion disc. This thin, rotating disc of material consists of the leftovers of a star which was ripped apart by the tidal forces of the black hole. [ESA/Hub- ble, M. Kornmesser]