Red dots in pairs: James Webb finds hints of black hole mergers in the early universe

Since the James Webb Space Telescope (JWST) began surveying the deep universe, it has revealed a family of objects that fit no previous catalog: extremely compact sources, of a characteristic red color, sitting at enormous cosmic distances. They are known as Little Red Dots (LRDs), and their nature remains one of the most intense debates in extragalactic astrophysics today.

A new study, published on August 31 in Publications of the Astronomical Society of Japan, adds an unexpected piece to that puzzle. An international team led by Takumi S. Tanaka analyzed infrared images from the JWST and identified four pairs of these red dots separated by only a few thousand light-years. The light from these systems set out some 12.5 to 12.8 billion years ago, when the universe was roughly one billion years old.

What the Little Red Dots are

The leading interpretation holds that each red dot harbors a supermassive black hole in full growth, wrapped in a dense cocoon of gas that absorbs its radiation and re-emits it at redder wavelengths. That would account for its color, its compactness and the surprising absence of X-ray emission. Even so, it is worth being clear: alternative models exist —from compact galaxies with intense star formation to hypothetical pulsating supermassive stars— and the matter is far from settled.

Pairs too close to be coincidence

The study’s key result is not merely finding red dots, but finding them in pairs. The authors report an excess of clustering on kilo-parsec scales; that is, more close pairs than one would expect from chance alignment on the sky. This points to physically associated systems rather than random projections. The images, built in false color from infrared filters at 1.5, 2.8 and 4.4 micrometers, show these pairs with a sharpness only the JWST can deliver today.

Here is where interpretation enters, and it must be named as such: if these objects contain black holes, finding them so close together suggests that some could be on their way to merging. If confirmed, mergers would be a growth channel that helps explain how the first supermassive black holes reached such enormous masses so soon after the Big Bang, one of the hardest open problems in cosmology.

What comes next

The very image-analysis method developed in the work opens a concrete path: applying it systematically to more JWST fields and statistically measuring what fraction of massive black holes form close pairs. That number would let astronomers quantify the real role of mergers in the earliest stages of black hole growth. For now, what we have is a solid, well-measured hint, not a definitive conclusion. The mystery of the Little Red Dots remains open, and this result makes it, if anything, more compelling.

© 2026 Homer Dávila Gutiérrez, FRAS — SKYCR.ORG. All rights reserved. Publication: Takumi S. Tanaka et al., Hidden in Pixels I: Discovery of dual «little red dots» indicates excess clustering on kilo-parsec scales, Publications of the Astronomical Society of Japan (2026). DOI: 10.1093/pasj/psag092