The framework proposes that some black holes formed from seeds weighing at least 100,000 to 1 million Suns.
Supermassive black holes weighing 100 million to 1 billion Suns have been observed at times when the universe was less than 700 million years old. The study argues that growing them from ordinary stellar remnants would require too much sustained growth, while some existing scenarios involving larger seeds rely on restrictive conditions or episodes of exceptionally rapid feeding.
Instead, the authors propose treating seeds of at least 100,000 to 1 million solar masses as an observationally constrained population, without committing to one formation process. They suggest these seeds formed in especially dense regions of the early universe and helped accelerate the assembly of galaxies and quasars.
What the model predicts
The framework reduces the required growth from about 18–20 e-folds—repeated multiplicative increases in mass—to at least 10. The authors say this can fit realistic periods of black-hole activity and the effects of feedback, such as energy released by growing black holes.
The model is intended to explain the relatively large black-hole-to-galaxy mass ratios found in compact, high-redshift systems without requiring extreme dust obscuration or finely tuned feedback. It predicts a higher fraction of compact early galaxies hosting central supermassive black holes, a population of leftover intermediate-mass black holes, and more early black-hole mergers.
Why the seeds matter
The proposal offers a way to explain how very massive black holes appeared so early without changing the standard model of cosmic expansion and structure formation. Its importance lies in making specific observational predictions rather than depending on one assumed mechanism for producing large seeds.
The predicted excess of black holes in compact early galaxies could be checked with James Webb Space Telescope surveys. Future observations of black-hole mergers and nearby black-hole environments could provide additional tests. If the most compact high-redshift galaxies do not show the predicted enhanced black-hole occupation, the framework would be directly falsified.
Evidence and open tests
This is a phenomenological framework: it uses observations to define plausible properties of a population of massive seeds rather than directly demonstrating how those seeds formed. The abstract presents parameter ranges and proposed tests, but does not report a new detection or a statistical result confirming the model.
The explanation therefore remains dependent on future observations. Its proposed signatures include an enhanced central black-hole occupation fraction in compact high-redshift galaxies, relic intermediate-mass black holes, and elevated early merger rates. The model is described as consistent with standard cosmology, but its validity will depend on whether these predictions are observed.
// Source
Communications of the Byurakan Astrophysical Observatory · 2026 · DOI: 10.52526/25792776-26.73.1-196
Authors: Vasily Bruilo
