A new simulation could help solve one of astronomy’s longstanding mysteries—how supermassive black holes formed so rapidly—along with a new one: What are the James Webb Space Telescope’s (JWST) “little red dots?”
Invisible leviathans lurk at the cores of nearly all of the 2 trillion or so galaxies strewn throughout space-time. Monster black holes entered the cosmic scene soon after the Universe’s birth and grew rapidly, reaching millions or even billions of times the Sun’s mass in less than a billion years. Astronomers have long wondered how these supermassive black holes could have grown so hefty in such little time.
The monster black hole mystery became even more perplexing in 2022 when “little red dots” were spotted at the far edges of space. When these tiny scarlet orbs began unexpectedly popping up in JWST images of the distant Universe, their nature was hotly debated. Now that scientists have amassed a sample of hundreds of them, many think the dots are growing supermassive black holes.
The problem is that they appear even earlier than astronomers thought possible, making the challenge of explaining early supermassive black holes even harder. Observations suggest that the little red dots mainly flickered on when the Universe was around 600 million years old and fizzled out within the next billion years (the supermassive black holes linger to the present time, but they no longer light up as little red dots).
A new study tries to explain the early formation of these immense objects via swelling swarms of stars.
Missing link
Many people thought it would violate the laws of physics for monster black holes to form so quickly. But a new study explains how colliding clusters of stars could have given rise to supermassive black holes within the Universe’s first several hundred million years—no new physics required.
“Right now, there are three main ideas for how supermassive black hole seeds form: direct collapse from gas clouds, remnants of the first stars, and dense star clusters,” said Fred Garcia, a graduate student at Columbia University who led the study. “Our work really supports the last case, where dense clusters evolve and their centers collapse to make intermediate-mass black hole seeds.”