A new analysis of the James Webb Space Telescope’s discoveries of tiny, bright objects called "Little Red Dots" (LRDs) shows that the universe may have produced supermassive black holes (SMBHs) with masses of at least a million suns when it was less than 1.5 billion years old. The objects’ inferred masses challenge standard models of black‑hole growth, which rely on slow accretion and mergers of small, Population III stars.

The study uses a Bayesian framework to explore how primordial density fluctuations that are slightly non‑Gaussian could create an enhanced population of primordial black holes (PBHs). Markov‑chain Monte Carlo simulations were run for two shapes of the power‑spectrum: a lognormal bump and a cut‑power‑law tail. For each shape the researchers varied the local non‑Gaussianity parameter |fNL| and the peak amplitude A, while also accounting for how quickly the black holes can gather gas at the Eddington rate. The analysis requires the models to stay below the upper bound on cosmic‑microwave‑background μ‑distortions set by COBE/FIRAS.

Results from the simulations show that both the lognormal and cut‑power‑law templates can match the observed number density of LRDs and keep μ below the observational limit, provided |fNL| is of order unity and A is about 10⁻³. The joint constraints are illustrated in Figure 3, which displays the allowed region in terms of μ and LRD abundance. The figure demonstrates that the required values of |fNL| are small enough to satisfy CMB limits, yet large enough to generate the needed PBH seeds.