LIGO may detect formation of black-hole binary stars: Study

Researchers from the University of Chicago have predicted that Laser Interferometer Gravitational-Wave Observatory (LIGO) would detect approximately 1,000 mergers of massive black holes annually once it achieves full sensitivity early next decade.

The prediction is based on computer simulations of more than a billion evolving binary stars. The simulations are based on state-of-the-art modeling of the physics involved, informed by the most recent astronomical and astrophysical observations.

Daniel Holz, assistant professor in physics and astronomy at the University of Chicago, said the main thing they found was that what LIGO detected makes sense. He added the simulations predicted the formation of black-hole binary stars in a range of masses that includes the two already observed.

Lead researcher Krzysztof Belczynski from the Warsaw University in Poland said the study showed that when LIGO reaches full sensitivity it would detect only one pair of colliding neutron stars for every 1,000 detections of the far more massive black-hole collisions.

Holz said there are dynamical processes by which those black holes get closer and eventually merge, adding identifying which black holes merged under which scenario is difficult. One potential method would entail examining the black holes' relative spins. Binary stars that evolved dynamically are expected to have randomly aligned spins; detecting a preference for aligned spins would be clear evidence in favor of the isolated evolutionary model.

"This study represents the first steps in the birth of the entirely new field of gravitational wave astronomy. We have been waiting for a century and the future has finally arrived," Daniel said.

The study is published in the journal of Nature.