Plasma jets firing from a supermassive black hole photographed by scientists

• Astronomers have photographed hot gas jets swirling out of a black hole in the heart of a nearby galaxy.
• Their findings suggest that all jets look the same, regardless of the mass of their black hole.
• In 2019, the same researchers zoomed in on a black hole 6.5 billion times the mass of our sun.

At the heart of every galaxy is a supermassive black hole, which consumes everything within the reach of its gravitational pull, that is, almost everything.

Scientists have spotted jets of plasma – streams of energy and hot matter – escaping the core of some black holes at one-third the speed of light. Researchers still don’t know how these jets form or escape from celestial voids. But a new study gives astronomers better insight into the relationship between jets and their black hole relatives.

Researchers from the Event Horizon Telescope collaboration – a group that reconstructed the very first image of a black hole two years ago – have imaged jets of plasma spewing from a black hole at the center of the Centaurus A galaxy, in about 13 million light years from Earth.

Their observations reveal that all jets closely resemble each other, regardless of the mass of their black hole. The size of the jets is simply scaled, which means that the smaller jets come from smaller black holes.

Courtesy of Michael Janssen / Radboud University / Event Horizon Telescope

Even the smallest of these jets can stretch far across the universe, however.

“They disperse to form gigantic hot gas bubbles 100,000 light years in size,” Michael Janssen, astronomer at the Max Planck Institute for Radio Astronomy and Radboud University and lead author of the new study.

Up close and personal with a supermassive black hole

To image the Centaurus A jet, the Janssen team relied on data collected in April 2017 by eight synchronized radio telescopes around the world, forming an instrument the size of the Earth. The image is therefore a reconstructed view, not a photograph.

“Think about looking in a mirror that you’ve shattered to pieces,” Janssen said. “Each fragment can show you a bit of your face. Using the limited information you get from each fragment, you can piece together what you look like.”

ALMA (ESO / NAOJ / NRAO), Goddi et al.

This is not the first time that scientists have examined jets of plasma from a black hole. In 2011, an international team also photographed the Centaurus A jets, but the new images are ten times more precise and 16 times sharper than previous ones.

“We have achieved a magnification factor of 1 billion,” Janssen said. “We are watching the jet with unprecedented resolution immediately in the region where it was just born and launched by the black hole.”

The sharpness helped researchers compare the jets from the Centaur A black hole – which is 55 million times more massive than our sun – to those escaping the galaxy Messier 87, about 54 million light years from Earth. The Messier 87 black hole is 6.5 billion times more massive than the sun.

The researchers also compared Centaurus A’s jets to those from other black holes of different masses.

Their findings ultimately support the idea that smaller black holes are scaled-down versions of their more massive counterparts – and act the same regardless of their mass or how quickly they accumulate matter and energy.

Magnetic fields could drive these jets at high speed

Event Horizon Telescope Collaboration / Maunakea Observatories via AP

Supermassive black holes are formed when stars collapse on themselves at the end of their life cycle.

Black holes spin so fast that they warp space-time, and their gravity attracts whatever is nearby. Because even light cannot escape, these forces create a single shadow in the form of a perfect circle in the center of the black hole. The edge of this circle is known as the event horizon.

This gravitational pull twists the light coming from the cloud of gas, dust, and space trash orbiting the center of the black hole – known as the accretion disk.

“Black holes feed on this accretion disk,” Janssen said. “But not all particles are swallowed up. Some are ejected by the black hole and escape in the form of these jets.”

NASA / JPL-Caltech / Reuters

Scientists haven’t yet figured out what powers these streams of escaped particles, but Janssen suggests that magnetic fields at the edges of a black hole help speed up jets.

(Two studies done in March by other members of the Event Horizon Telescope team found evidence of a magnetic field near the event horizon of the Messier 87 black hole.)

“As the black hole spins, these magnetic fields start to be drawn in and transform into a corkscrew structure,” Janssen said.

During this time, the winding magnetic field collects the incoming particles. Then the field shoots outward and projects hot gas and energy away from the black hole. The strength of the magnetic field is enough to help some particles resist the gravity of a black hole.

According to Janssen, the resulting jets are breathtakingly sized.

“If you could see these jets and Centaur A’s black hole from Earth, the black hole would appear as big as an apple on the moon’s surface,” he said, “while the jets would be 16. times wider than the moon itself. “