A greater cosmic mystery was revealed by the JWST as they were seen to possess supermassive black holes just a few hundred million years after the Big Bang. Old theories were powerless to account for the rapid growth of such black holes. Researchers from Maynooth University have now revealed a theory that indicates there was a ‘cosmic feeding frenzy’ that enabled baby black holes to feed on gas at an unprecedented rate. “We found chaotic conditions,” the lead researcher Daxal Mehta said.
Super-Eddington Feeding Frenzy
In the new study, simulations show early black holes could gobble gas much faster than usual. Normally, a black hole’s own radiation blows away infalling matter beyond a set rate (the Eddington limit). But the first galaxies were gas-rich and turbulent, allowing short bursts of super-fast feeding known as “super-Eddington” accretion.
During these gluttonous phases, baby black holes balloon to tens of thousands of times the Sun’s mass. “These early black holes, while small, are capable of growing spectacularly fast,” Mehta said.
Implications for Early Black Holes
Maynooth researcher Lewis Prole calls this finding a breakthrough that “unlocks one of astronomy’s big puzzles”: explaining how cosmic giants appeared so early. By showing that even ‘light seed’ black holes could bulk up quickly, the research helps explain JWST’s puzzling finds. Previously, scientists thought only exotic ‘heavy’ seeds could spawn the early giants.
Dr John Regan notes, “Heavy seeds are somewhat more exotic and may need rare conditions to form. Our simulations show that your ‘garden variety’ stellar mass black holes can grow at extreme rates in the early universe.”. In other words, ordinary black holes might suffice to seed the first quasars, solving the mystery of their rapid growth.
