The 'Most Naked' Massive Black Hole QSO1 Discovered, Accounting for Over 2/3 of Galaxy Mass

IT Home news on May 28: Tech media Ars Technica published an article today (May 28), astronomers used the James Webb Space Telescope (JWST) to further confirm that the "little red dot" Abell 2744−QSO1 in the early universe is a supermassive black hole with almost no surrounding stars.

IT Home note: Abell 2744−QSO1 (or QSO1 for short) is an early-universe active galactic nucleus (AGN) reddened by dust and affected by strong gravitational lensing. It is widely accepted that this object formed roughly 700 million years after the Big Bang.

The research team reconstructed a fine image of its surrounding environment. They compared the brightness of different regions and measured the redshift and blueshift of hydrogen emission lines to determine the direction of gas movement toward and away from Earth.

International team results showed that one side of the object was redshifted and the other blueshifted, consistent with the characteristic of matter rotating around a central object. The team also analyzed velocity dispersion to determine whether this material's motion was concentrated and dominated by a single massive gravitational source.

Subsequently, researchers plugged observational data into multiple models. The best fit was the scenario of "a central massive point mass source with surrounding material rotating around it," i.e., a supermassive black hole-dominated system.

Model estimates place its mass at approximately 50 million times that of the Sun, while the upper limit for surrounding total stellar mass is only 20 million solar masses — meaning over 2/3 of the mass is concentrated within the black hole.

This upper limit makes QSO1 the "most naked" massive black hole known — meaning the black hole dominates almost the entire system, with researchers even placing quotes around the term "galaxy."

This result also raises an even bigger question: How did such a large black hole form so soon after the universe began? The paper discussed three main hypotheses:

First: Primordial black holes formed shortly after the Big Bang

Second: Direct collapse of massive gas clouds, skipping the star formation phase

Third: Continuous merging of numerous black holes in early high-density star clusters, leading to rapid mass gain

However, since QSO1 has no dense surrounding star cluster, it would be difficult to form enough black holes first and then merge them step by step into a supermassive one — making this hypothesis very weak.

The paper also noted that many existing direct collapse models often require an intense UV radiation source and more surrounding material than observed for QSO1, making the primordial black hole scenario seem more favorable.