New method makes easier the detection of black holes

The study, prepared with physicists from other countries, has been published in the prestigious scientific journal Physical Review Letters

21 June, 2011

Black holes are not at all easy to detect. Nevertheless, their study is one of the hottest topics in astronomy, since it may provide important clues on issues as profound as how the universe started. Now, they might be easier to identify, thanks to a new method devised by Sascha Husa and Denis Pollney, researchers from UIB, along with collaborators from the California Institute of Technology, University of Vienna, Cardiff University, Friedrich Schiller Universität Jena and the Max- Planck-Institut für Gravitationsphysik in Potsdam.

The method has been published in the June issue of the journal Physical Review Letters and focuses on the detection of systems of two black holes through the gravitational waves generated by them. Gravitational waves are ripples in the fabric of space-time created when extremely massive bodies move very quickly. A particularly important case in astrophysics is when two black holes orbit around each other. Gradually, the two black holes get closer until they fall onto each other. During the last few orbits, the strongest and most interesting part of the signal is emitted and this is when you can apply the method developed by Sascha Husa and collaborators. Due to the complexity of the calculations, supercomputers such as Mare Nostrum in Barcelona are required to compute the motion of the black holes and their gravitational waves.

Sascha Husa and Denis Pollney are members of the Relativity and Cosmology group at UIB, which specializes in the study of gravitational waves. As an indicator of the excellence of the group, professor Husa has been recently appointed one of the two spokespersons for the international collaboration "Ninja II". This project aims to combine the solutions to Einstein's equations with the data collected by gravitational wave detectors to develop the best techniques to search for these faint signals from distant regions of the universe.

Although there were already methods to identify black hole systems, the new technique is more sophisticated and makes their detection much more likely. The main difference is that this method takes into account a fundamental characteristic of many black holes - they spin. Like the Earth, most of these objects also rotate around themselves. However, adding this factor into the calculations makes them much more difficult, and this is why previously it had not been possible to efficiently search for spinning black holes in the detector data. It is estimated that this technique will increase up to five times the likeliness to detect gravitational waves from these black holes systems.

Gravitational waves were predicted by Einstein in 1916, but they have not yet been detected directly due to the degree of technical difficulty. This is why the new method is especially important, since black holes systems are one of the most promising sources of these waves. The discovery of gravitational waves will open a new window on the Universe that could lead to discoveries that we can not even imagine.

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