Webb Spectrum Backs Black Hole Star Model for 1 Early-Universe Little Red Dot

3 articles · Updated · spacedaily.com · Jul 14

GLIMPSE-17775, a compact red object seen 1.8 billion years after the Big Bang, now offers the strongest single-object evidence that some “little red dots” are black hole stars rather than impossibly dense stellar systems.
More than 40 spectral features from 30 hours of Webb NIRSpec data — boosted to roughly 80 hours by gravitational lensing — point to a powerful source buried in thick gas that reprocesses its radiation into a star-like glow.
Sixteen iron lines, broad hydrogen features better explained by electron scattering, and helium fluorescence all support a dense cocoon around a rapidly accreting black hole, helping explain why many little red dots lack strong X-ray signals.
A separate object, 3DHST-AEGIS-12014, shows little-red-dot traits plus detectable X-rays, suggesting some may be transitional cases as their cocoons thin and they evolve toward ordinary active galactic nuclei.
Astronomers still do not think every little red dot is the same object, but the new spectrum sharply reduces the need to invoke unrealistically massive, mature galaxies in the early universe.

Sources

spacedaily.com11h ago

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JWST’s “Little Red Dots”: Unveiling Black Hole Stars and the Rapid Growth of Supermassive Black Holes in the Early Universe

Overview

The launch of the James Webb Space Telescope (JWST) marked a turning point in astronomy, enabling the discovery of mysterious 'little red dots' (LRDs) in 2022. These compact, intensely red objects were first hinted at by earlier telescopes like Hubble, but only JWST’s advanced infrared capabilities could reveal their true nature. The red color comes from the universe’s expansion stretching their light to longer wavelengths. The abundance and brightness of LRDs in the early universe challenged existing theories, prompting new models and reshaping our understanding of how galaxies and black holes formed and evolved in cosmic history.

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