Among the stranger discoveries of the James Webb Space Telescope are the little red dots, compact crimson objects in the early universe thought to be rapidly growing black holes feeding on surrounding matter. Researchers at the University of Tokyo's Kavli Institute for the Physics and Mathematics of the Universe have now found four candidate pairs of these objects, each consisting of two little red dots lying remarkably close together.
The team developed a new image analysis method and applied it to high-resolution infrared imaging from the telescope, identifying pairs dating to roughly 12.5 to 12.8 billion years ago. For two of the pairs, spectroscopic data showed the companions share nearly identical redshifts, strong evidence that they are genuine neighbours rather than chance alignments along the line of sight.
The result, published in Publications of the Astronomical Society of Japan, bears on one of astrophysics' sharpest puzzles: how supermassive black holes assembled so quickly after the Big Bang. The group now plans to extend the search and measure statistically what fraction of little red dots form close pairs, a step towards quantifying how much merging contributed to early black hole growth.