A team of astronomers in the UK has made a massive discovery, using gravitational lensing to locate one of the biggest black holes to date.
At 32.7 billion solar masses, this ultramassive black hole is positioned in center of the gigantic elliptical galaxy Abell 1201 BCG, in the galaxy cluster Abell 1201, some 2.7 billion light-years away from Earth.
The Durham University astronomers made their discovery with the aid of DiRAC COSMA8 supercomputing, creating hundreds and thousands simulations of light traveling through the universe and being able to match one model to a real path that had been captured by NASA's Hubble Space Telescope.
“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,” said lead author James Nightingale, from the Centre for Extragalactic Astronomy at Durham University.
It’s the first black hole found using this technique, but gravitational lensing has been used before to probe space from Earth, enabling the exploration of supernovae, distant colliding galaxies and to seek out other black holes. Gravitational microlensing has even been put to work to spy distant smaller objects, like a single star.
In this case, gravitational lensing, which uses a foreground galaxy to bend light from a distant object and magnify it, allowed scientists to measure the ultramassive black hole – thanks largely to Abell 1201 being such an exemplary gravitation lens. But it opens the door to better understand the mysteries of black holes and the space around them.
“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,” said Nightingale. “However, gravitational lensing makes it possible to study inactive black holes, something not currently possible in distant galaxies.”
Their findings are the culmination of nearly 20 years of work, dating back to 2004 when Durham University astronomer Alastair Edge spotted the enormous arc of a gravitational lens while reviewing galaxy images. The Hubble data and the supercomputing technology allowed the team to revisit their initial discovery.
“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,” Nightingale added.
Currently, the most massive black hole we know of is TON 618, which is believed to be 66 billion solar masses.
The study was published in the journal Monthly Notices of the Royal Astronomical Society.
In the video below, see how gravitational lensing tipped the team off about the black hole's existence.
Source: Durham University
