Gravitational lensing reveals one of the biggest black holes ever found

Scientists have discovered a black hole with a mass 32.7 billion times that of our Sun and located 2.7 billion light years from Earth. The discovery is the fruit of research coordinated by James Nightingale of the UK’s University of Durham based on data collected by the Hubble Space Telescope. The findings are published in the Monthly Notices of the Royal Astronomical Society.

The ultramassive black hole is concentrated in a relatively small space at the centre of Abell 1201, a galaxy lying at the centre of a large cluster composed of thousands of other galaxies. "It is certainly one of the largest black holes ever identified, and that's enough to make it interesting,” commented Crescenzo Tortora of the Capodimonte Astronomical Observatory of the Italian Institute for Astrophysics (Inaf).

“However, what makes the work even more important is the method by which it was identified, which is the use of a gravitational lens”, namely a phenomenon of light distortion due to the presence of large masses; the phenomenon was predicted by the theory of relativity but has only started to be used in a concrete way in recent years, opening up new frontiers of astronomy. In this case, it made it possible to 'weigh' the black hole at the centre of Abell 1201 and accurately measure its incredible mass.