Gravitational light-bending reveals one of the largest black holes ever discovered

A team of astronomers has discovered one of the largest black holes ever discovered, taking advantage of a phenomenon called gravitational lensing.

The team, led by Durham University in the UK, used gravitational lensing – where a foreground galaxy bends and magnifies light from a distant object – and supercomputer simulations at the DiRAC HPC facility, which enabled the team to closely examine how light is bent by a black hole within a galaxy. ​Hundreds of millions of light years away from Earth.

They found a supermassive black hole, an object more than 30 billion times the mass of our Sun, in the foreground galaxy, a scale rarely seen by astronomers.

This is the first black hole discovered using this technique, as the team simulates light traveling through the universe hundreds of thousands of times. Each simulation includes a different mass black hole, which alters the light’s journey to Earth.

When the researchers included a supermassive black hole in one of their simulations, the path taken by light from the distant galaxy to reach Earth matched the path seen in real images taken by the Hubble Space Telescope.

The results were published today in the journal Monthly Notices of the Royal Astronomical Society.

A video showing how astronomers used gravitational lensing to discover a black hole 30 billion times the mass of the Sun in a galaxy 2 billion light-years away. Credit: Durham University

Lead author Dr James Nightingale, Durham University’s Department of Physics, said: “This particular black hole, about 30 billion times the mass of our Sun, is one of the largest ever discovered and at the upper limit of how big we can be. We think black holes can becoming a theoretician, so it’s a very exciting discovery.”

Gravitational lensing occurs when the gravitational field of a foreground galaxy appears to bend the light of a background galaxy, which means we notice it more often.

Like a real lens, this one also magnifies the background galaxy, allowing scientists to study it in enhanced detail.

Video still image – black hole – lens geometry. Credit: Durham University

Video still image – black hole – observed image. Credit: Durham University

Dr. Nightingale said: “Most large black holes that we know of are in an active state, where matter being pulled close to the black hole heats up and releases energy in the form of light, X-rays and other radiation.”

However, gravitational lensing makes it possible to study inactive black holes, something that is not currently possible in distant galaxies. This approach could allow us to detect many more black holes outside our local universe and reveal how these exotic objects evolved back in cosmic time. .”

The study, which also involves Germany’s Max Planck Institute, opens up the tantalizing possibility that astronomers can discover inactive, more massive black holes than previously thought, and investigate how they grow so massive.

The story of this very discovery began in 2004 when fellow Durham University astronomer Professor Alastair Edge noticed a giant arc of a gravitational lens when reviewing SGS images.

Video still image – black hole – integer mass. Credit: Durham University

Video still image of a supermassive supermassive black hole. Credit: Durham University

Video still image of a black hole – very low mass. Credit: Durham University

Fast forward 19 years and with the help of some high resolution images from NASA’s Hubble Telescope and the DiRAC COSMA8 supercomputer facility at Durham University, Dr. Nightingale and his team were able to revisit this and explore it further.

The team hopes that this is the first step in enabling a deeper exploration of the mysteries of black holes, and that future large-scale telescopes will help astronomers study distant black holes to learn more about their magnitude and size.