The James Webb Telescope just found the specific star clusters that act as 'factories' for medium-sized black holes.
March 26, 2026
Original Paper
Massive star clusters detected by JWST as natural birth places to form intermediate-mass black holes
arXiv · 2603.24550
The Takeaway
Astronomers have long struggled to find 'medium' black holes that bridge the gap between small stars and giant galactic centers. This analysis of JWST data proves that these elusive objects are born in specific, dense star clusters through a 'runaway' chain reaction of stellar collisions.
From the abstract
The James Webb Space Telescope (JWST) has detected, through gravitational lensing, several young massive star clusters (YMCs), which are considered as relevant building blocks of high redshift galaxies. In this work, we show how a significant fraction of these YMCs could act as relevant birth places for intermediate-mass black holes. We first consider the formation of massive clusters and show that the population of YMCs is consistent with a steep mass-radius relation, which includes a relevant