NASA’s Chandra spots fastest-growing black hole in early universe

An artist’s concept of a supermassive black hole, a surrounding disk of material falling towards the black hole and a jet containing particles moving away at close to the speed of light. This black hole represents a recently-discovered quasar powered by a black hole. New Chandra observations indicate that the black hole is growing at a rate that exceeds the usual limit for black holes, called the Eddington Limit.(Image: NASA/CXC/SAO/M. Weiss)

Astronomers have spotted one of the fastest-growing black holes ever recorded, raising fresh questions about how such giants emerged so soon after the Big Bang.

What makes this black hole so unusual?
The black hole, named RACS J0320-35, is about a billion times heavier than the Sun. It lies 12.8 billion light years from Earth, meaning we see it as it was just 920 million years after the universe began. Observations from NASA’s Chandra X-ray Observatory show it producing more X-rays than any other black hole spotted in the universe’s first billion years.

This activity reveals that the black hole is growing at a rate above the normal threshold. That limit, called the Eddington limit, describes the maximum rate at which material can fall in without being pushed back by radiation pressure.

How are scientists explaining the rapid growth?
The black hole powers a quasar, a blazing object brighter than whole galaxies. Matter is funnelling into it faster than expected, possibly at 2.4 times the Eddington limit. Researchers say this suggests it may not need an unusually massive birth to reach its current size. Instead, it could have started with a smaller mass, less than a hundred Suns, from the collapse of a star.

Luca Ighina, who led the study, said the team was “shocked” by the pace of growth. Co-author Alberto Moretti added that working backwards from the mass allows scientists to test new theories of black hole origins.

What does this mean for the wider universe?
The discovery may explain how black holes reached enormous sizes in the early universe. It also raises new questions about rare jets of particles, seen moving near light speed from RACS J0320-35. Such jets are uncommon for quasars, which hints that the fast growth may be linked to their creation.

The object was first discovered in a radio survey with the Australian Square Kilometre Array Pathfinder, then confirmed with data from Chilean observatories. Chandra’s X-ray spectrum gave crucial evidence of the black hole’s rapid expansion, while optical and infrared data supported the result.

Scientists believe the black hole is adding mass at a rate between 300 and 3,000 suns per year. A paper describing the findings has been accepted for publication in The Astrophysical Journal.