Researchers from Cardiff University have used computer simulations of black holes to show that the gravitational waves they emit can reveal details of the primordial collision that created them in the first place.
Kilometre-sized laser interferometers are currently being built in the USA, Europe, Japan, and India to detect gravitational waves from colliding black holes and other cosmic events. The Cardiff calculations, which will appear in Physical Review Letters, mean that the data from these interferometers could be more valuable than previously thought.
By comparing the strengths of different frequencies, ‘it is possible not only to learn about the final black hole, but also the properties of the original two black holes that took part in the collision,’ explained Ioannis Kamaretsos, who performed the simulations as part of his PhD research.
He added, ‘It is exciting that the details of the late in-spiral and merger are imprinted on the waves from the deformed final black hole. If General Relativity is correct, we may be able to make clear how very massive black holes in the centres of galaxies have shaped galactic evolution.’
Two black holes orbiting around each other emit gravitational waves and lose energy, eventually spiralling into each other to produce a single, initially highly deformed, black hole which emits a mixture of gravitational waves of different frequencies.
Astronomers have long believed that by measuring the frequencies of its gravitational radiation, one can measure the mass and spin of a black hole. ‘We never guessed it would be possible to weigh two black holes after they've collided and merged,’ said Dr Mark Hannam.
‘We might even be able to use these results to test Einstein's general theory of relativity. We can compare the waves we observe from the orbiting black holes with the waves from the merged black hole, and check whether they are consistent,’ he added.
The finding comes just as seven new PhD studentships in computational science have been announced at Welsh Universities, as part of a collaboration between Fujitsu and High Performance Computing Wales. HPC Wales provides business and academic researchers in the country with advanced computing technology and also the training, outreach and technical support to exploit supercomputing technology effectively. It is part-funded by the Welsh Government and the European Regional Development Fund.
The successful projects will use HPC Wales’s infrastructure, powered by Fujitsu Primergy clusters and will also have access to HPC specialists from Fujitsu Laboratories of Europe and Fujitsu’s Technical Computing Solutions Unit.
