Ultra-dense stellar clusters as black hole nurseries

A study published in Astronomy & Astrophysics proposes that ultra-dense stellar clusters observed by the James Webb Space Telescope (JWST) may be the birthplaces of supermassive black holes. Researchers led by Viola Bocchi suggest that these clusters could act as "nurseries" for "heavy seeds" that eventually grow into supermassive black holes.

Cosmic gems with unique properties

The observed clusters, referred to as "cosmic gems," were seen 460 million years after the Big Bang. They are noted for their extreme compactness and low content of heavy elements, conditions that may lead to frequent stellar collisions and fusions. These processes could create heavy seeds with masses between 1,600 and 2,700 times that of the Sun, ideal for forming supermassive black holes.

Evidence from distant galaxy Firefly Sparkle

In a distant galaxy called "Firefly Sparkle," observed 600 million years after the Big Bang, the JWST identified ten young stellar clusters. These clusters produce smaller seeds ranging from 180 to 810 solar masses, supporting the idea that this formation mechanism is not unique. This finding may also explain the origins of the mysterious "Little Red Dots" seen in the early universe.

Limitations and uncertainties

The researchers caution that they have not directly observed the birth of supermassive black holes. While their models suggest these clusters could be viable sites for black hole formation, there are uncertainties about the clusters’ internal rotation, three-dimensional structure, and initial mass. These factors contribute to the margin of uncertainty in the final masses of the potential seeds.

A foundation for understanding early black holes

Despite these uncertainties, the study provides a tangible physical basis for understanding how supermassive black holes may have formed in the early universe. This research offers a new perspective on the origins of these massive cosmic objects.