An article published in “The Astrophysical Journal Letters” reports the discovery of the best evidence so far of the existence of intermediate-mass black holes. A team of researchers led by Dacheng Lin of the University of New Hampshire used the Hubble Space Telescope for a follow-up study based on X-ray data collected by other space telescopes that observed the source cataloged as 3XMM J215022.4-055108. The result is that this source is located in a dense star cluster on the periphery of another galaxy and the characteristics indicate that it’s an intermediate-mass black hole with a mass over 50,000 times the Sun’s.