Scientists find a large black hole that “hiccups,” giving off plumes of gas.

Credit: Jose-Luis Olivares/MIT.

Far away in a distant galaxy, about 800 million light years from Earth, a supermassive black hole has been caught behaving oddly, almost like it had a case of the hiccups.

Scientists, including a team from MIT and other countries, discovered this black hole suddenly burping out gas every 8.5 days, then returning to its quiet state.

This kind of behavior in black holes has never been seen before and has left astronomers buzzing with excitement.

Usually, we imagine black holes as cosmic vacuum cleaners, sucking in everything around them. But this black hole’s periodic gas plumes suggest there’s much more going on.

The researchers think a smaller black hole might be orbiting the big one, diving into its gas disk every 8.5 days, flinging gas out into space each time it passes through.

Published in the journal Science Advances, these findings shake up our previous understanding of black holes and their surroundings.

Black holes are often surrounded by a disk of gas that swirls around them, kind of like water going down a drain.

Until now, scientists thought these gas disks were pretty straightforward, but this discovery suggests they might actually host other black holes or even stars.

“We thought we knew a lot about black holes, but this is telling us there’s so much more they can do,” says Dheeraj “DJ” Pasham from MIT, one of the study’s authors. The team includes researchers from across the globe, such as Italy and the Czech Republic.

This discovery came about almost by accident. An automated survey of the sky, designed to spot supernovas and other cosmic events, caught a burst of light from the galaxy in question.

The galaxy, which had been quiet, suddenly lit up a thousand times brighter. Pasham saw this alert and decided to point NASA’s NICER telescope at it. NICER is an X-ray telescope on the International Space Station that looks out for X-ray bursts, which can signal black hole activity among other things.

The telescope observed the galaxy as it continued to flare up for about four months. When analyzing the data, Pasham noticed the galaxy’s energy dipped in a regular pattern every 8.5 days.

It was a clue that something was orbiting within the black hole’s gas disk, periodically blocking some of the energy being emitted.

A theory from Czech scientists fit perfectly with these observations. They had proposed that a supermassive black hole could have a smaller companion black hole orbiting it at an angle, punching through the gas disk and flinging gas out into space in a regular pattern.

To confirm their theory, the team used simulations that matched NICER’s observations.

They think that before the outburst in December 2020, a star wandered too close to the supermassive black hole and got torn apart by its gravity, lighting up the black hole’s surroundings.

As the supermassive black hole feasted on the remains of the star, the smaller black hole continued its orbit, puncturing the gas disk and causing the observed hiccups.

This discovery suggests that there might be many more black holes out there with companions, challenging our previous notions of black holes and their environments. “This is a different beast,” Pasham says, excited about the potential for future discoveries.

The study not only reveals new behaviors of black holes but also points to the possibility of detecting more such systems, which could be crucial for understanding the universe’s gravitational waves.

Richard Saxton, an X-ray astronomer who wasn’t involved in the study, likens the discovery to using a fluorescent dye to find a leak in a pipe, highlighting how disrupted star debris can illuminate the mysteries of galactic centers.

This finding hints that binary supermassive black holes might be more common than previously thought, opening new frontiers for gravitational wave research.