BBC Sky at Night Magazine
Black holes are big babies
Astronomers have discovered that infant supermassive black holes are much larger than expected, potentially explaining their rapid growth. The giant black holes have been spotted in the Universe just 800 million years after the Big Bang, but astronomers have struggled to explain how they reached their enormous size that quickly.
A new study could potentially hold the answer, by looking not at the growth of the black hole itself, but at how its initial ‘seed’ formed. These infant black holes formed in the gas-rich centres of early galaxies, where many extremely large stars formed.
“The biggest stars live a short time and very quickly evolve into stellar black holes, as large as several scores of solar masses. They are small, but many form in these galaxies,” says Lumen Boco from Scuola Internazionale Superiore di Studi Avanzati, who led the study.
The study showed these black holes then merge together, forming a seed as large as 100,000 solar masses – much larger than first
thought and giving black holes the early boost they need to grow to the sizes we see today. www.sissa.it