Globular clusters could be factories of binary black holes

Astronomers have detected dense star clusters that they claim could be the factories of binary black holes.

The coalescence of two black holes, a very violent and exotic event, is one of the most sought-after observations of modern astronomy. But, as these mergers emit no light of any kind, finding such elusive events has been impossible so far.

The first observatories capable of directly detecting these 'gravity signals' ripples in the fabric of spacetime first predicted by Albert Einstein 100 years ago, would begin observing the universe later this year.

When the gravitational waves rolling in from space are detected on Earth for the first time, a team of Northwestern University astrophysicists predicts astronomers will "hear," through these waves, five times more colliding black holes than previously expected.

Senior author of the study and theoretical astrophysicist Frederic A. Rasio said that their study indicates the observatories potentially could detect 100 merging binary black holes per year forged in the cores of these dense star clusters than previously thought.

Rodriguez and colleagues used detailed computer models to demonstrate how a globular cluster acts as a dominant source of binary black holes, producing hundreds of black hole mergers over a cluster's 12-billion-year lifetime.

Advanced LIGO (Laser Interferometer Gravitational-Wave Observatory) is one of the new gravitational-wave observatories. Slated to begin operation later this year, Advanced LIGO is a large-scale physics experiment designed to directly detect gravitational waves of cosmic origin. Laser interferometers detect gravitational waves from the minute oscillations of suspended mirrors set into motion as the waves pass through the Earth.

The study is published by the journal Physical Review Letters.