Light-bending gravity reveals one of the biggest black holes ever found

An image of the Milky Way warped around a small black circle at the centre of the image.
An artist’s impression of a black hole, where the black hole’s intense gravitational field distorts the space around it. This warps images of background light, lined up almost directly behind it, into distinct circular rings. This gravitational "lensing" effect offers an observation method to infer the presence of black holes and measure their mass, based on how significant the light bending is. The Hubble Space Telescope targets distant galaxies whose light passes very close to the centers of intervening foreground galaxies, which are expected to host supermassive black-holes over a billion times the mass of the sun.
ESA/Hubble, Digitized Sky Survey, Nick Risinger (, N. Bartmann

A team of astronomers have discovered one of the biggest black holes ever found, taking advantage of a phenomenon called gravitational lensing. The findings are published in Monthly Notices of the Royal Astronomical Society.

The team, led by Durham University, UK, used gravitational lensing - where a foreground galaxy bends the light from a more distant object and magnifies it – and supercomputer simulations on the DiRAC HPC facility, enabled the team to closely examine how light is bent by a black hole inside a galaxy hundreds of millions of light years from Earth.

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

This is the first black hole found using the technique, whereby the team simulates light travelling through the Universe hundreds of thousands of times. Each simulation includes a different mass black hole, changing light’s journey to Earth.

When the researchers included an ultramassive black hole in one of their simulations the path taken by the light from the faraway galaxy to reach Earth matched the path seen in real images captured by the Hubble Space Telescope.

A gravitational lens occurs when the gravitational field of a foreground galaxy appears to bend the light of a background galaxy, meaning that we observe it more than once.

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

The study, which also includes Germany’s Max Planck Institute, opens up the tantalising possibility that astronomers can discover far more inactive and ultramassive black holes than previously thought, and investigate how they grew so large.

The story of this particular discovery started back in 2004 when fellow Durham University astronomer, Professor Alastair Edge, noticed a giant arc of a gravitational lens when reviewing images of a galaxy survey.

Fast forward 18 years and with the help of some extremely high-resolution images from NASA’s Hubble telescope and the DiRAC COSMA8 supercomputer facilities 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 even more distant black holes to learn more about their size and scale.

The research was supported by the UK Space Agency, the Royal Society, the Science and Technology Facilities Council (STFC), part of UK Research and Innovation (UKRI), and the European Research Council.

This work used both the DiRAC Data Intensive Service (CSD3) and the DiRAC Memory Intensive Service (COSMA8), hosted by University of Cambridge and Durham University on behalf of the DiRAC High-Performance Computing facility.

Lead author Dr James Nightingale, Department of Physics, Durham University, said: “This particular black hole, which is roughly 30 billion times the mass of our Sun, is one of the biggest ever detected and on the upper limit of how large we believe black holes can theoretically become, so it is an extremely exciting discovery.”

Dr Nightingale said: “Most of the biggest black holes that we know about are in an active state, where matter pulled in 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 not currently possible in distant galaxies. This approach could let us detect many more black holes beyond our local universe and reveal how these exotic objects evolved further back in cosmic time.”

Media Contacts

Gurjeet Kahlon
Royal Astronomical Society
Mob: +44 (0)7802 877 700

Dr Robert Massey
Royal Astronomical Society
Mob: +44 (0)7802 877699


Science Contacts

Dr James Nightingale
Department of Physics, Durham University


Further information

The research appears in ‘Abell 1201: Detection of an Ultramassive Black Hole in a Strong Gravitational Lens’, Nightingale et al., Monthly Notices of the Royal Astronomical Society, in press.

James Nightingale’s work was supported by the UK Space Agency Grant ST/N001494 and ST/W002612 and the Royal Society Short Industry Fellowship.

Russel Smith’s work was supported by a Royal Society University Research Fellowhsip and the Science and Technology Facilities Council (STFC).

Jacob Kegerreis acknowledges support from a NASA Postdoctoral Program Fellowship.

Amy Etherington was supported by grants ST/R504725 and ST/T50604 from the STFC.

Aristeidis Amvrosidais and Qiuhan He acknowledge support from the European Research Council grant DMIDAS (GA 786910)

This work used both the DiRAC Data Intensive Service (CSD3) and the DiRAC Memory Intensive Service (COSMA8), hosted by University of Cambridge and Durham University on behalf of the DiRAC High-Performance Computing facility.

The DiRAC HPC facility is funded BEIS and STFC. 


Notes for Editors

The Royal Astronomical Society (RAS), founded in 1820, encourages and promotes the study of astronomy, solar-system science, geophysics and closely related branches of science. The RAS organises scientific meetings, publishes international research and review journals, recognises outstanding achievements by the award of medals and prizes, maintains an extensive library, supports education through grants and outreach activities and represents UK astronomy nationally and internationally. Its more than 4,000 members (Fellows), a third based overseas, include scientific researchers in universities, observatories and laboratories as well as historians of astronomy and others.

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We conduct boundary-breaking research that improves lives globally and we are ranked as a world top 100 university with an international reputation in research and education (QS World University Rankings 2023).


About Durham University

Durham University is a globally outstanding centre of teaching and research based in historic Durham City in the UK.

We are a collegiate university committed to inspiring our people to do outstanding things at Durham and in the world.

We are a member of the Russell Group of leading research-intensive UK universities and we are consistently ranked as a top 10 university in national league tables (Times and Sunday Times Good University Guide, Guardian University Guide and The Complete University Guide).

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About DiRAC

DiRAC stands for Distributed Research Using Advanced Computing. The DiRAC High Performance Computing facility provides cutting-edge supercomputing resources for UK researchers working on world-leading scientific calculations across a wide range of areas including particle physics, astrophysics, cosmology and nuclear physics.

It comprises supercomputers at Cambridge, Durham, Leicester and Edinburgh, each designed to support specific types of calculations.  DiRAC also provides access to a team of expert research software engineers to help researchers make the most efficient use of the available computing resources.

For more details see:

Submitted by Gurjeet Kahlon on Wed, 29/03/2023 - 09:25