An international team of astronomers, including from the University of Southampton and Inter-University Centre for Astronomy and Astrophysics (IUCAA), have used state-of-the-art cameras to create a high frame-rate movie of a growing black hole system at a level of detail never seen before. In the process, they have uncovered new clues to understanding the immediate surroundings of these enigmatic objects.
An official statement issued Friday said that John Paice, a joint PhD student at the University of Southampton, UK and IUCAA, Pune, was the lead author of the study and also the artist who created the movie. He is part of an Indo-UK programme led by Professor Poshak Gandhi of University of Southampton and Professor Ranjeev Misra of IUCAA.
The black hole system is ‘MAXI J1820+070’, at least 10,000 light years away, and was first discovered in 2018. Its mass is the equivalent of seven Suns compressed into a region smaller than the city of London. Black holes can feed off a nearby star and create vast accretion discs of material. Here, the effect of the black hole’s strong gravity and the material’s own magnetic field can cause rapidly changing levels of radiation, which are emitted from the system as a whole.
This radiation is what was detected in visible light by the HiPERCAM instrument on the Gran Telescopio Canarias (La Palma, Canary Islands, Spain) and in X-rays by NASA’s NICER observatory aboard the International Space Station (ISS). Investigating these systems is usually very difficult, as their distances make them too faint and too small to see. These kinds of observations are not possible even by the Event Horizon Telescope (EHT), which recently took a picture of the black hole at the centre of the galaxy M87.
However, the HiPERCAM and NICER instruments allowed researchers to record ‘movies’ of the changing light from the system at over 300 frames per second, capturing violent ‘crackling’ and ‘flaring’ of visible and X-ray light. A split second time difference between X-ray and visible light (as illustrated in the movie) has been seen in two other systems hosting black holes but it has never been observed at this level of detail.
Paice explained that the movie was made using real data, but slowed down to 1/10th of actual speed to allow the most rapid flares to be discerned by the human eye. Professor Somak Raychaudhury, director, IUCAA, said, “Path-breaking discoveries like this often need collaborators and facilities from across the world bringing together a whole range of skills and instruments. I am so glad that IUCAA has been able to play a leading role in this discovery and I hope this collaboration will continue to produce more stunning results.”