LIGO’s 1st detection of merging black holes ‘perfectly consistent’ with Northwestern model. In a new study, the scientists show their theoretical predictions last year were correct: The historic merger of 2 massive black holes detected Sept. 14, 2015, could easily have been formed through dynamic interactions in the star-dense core of an old globular cluster. These binary black holes are born in the chaotic “mosh pit” of a globular cluster, kicked out of the cluster and then eventually merge into one black hole. This theory, known as dynamical formation, is 1 of 2 main channels for forming binary black holes detected by Advanced LIGO (Laser Interferometer Gravitational-Wave Observatory).
Colliding black holes do not emit light; however, they do release a phenomenal amount of energy as gravitational waves. The first detection of these waves occurred Sept. 14, and the second – announced yesterday- occurred 3 months later. These events have launched a new era in astronomy: using gravitational waves to learn about the universe. “Thanks to LIGO, we’re not just theorists speculating anymore – now we have data,” said Frederic A. Rasio. “A relatively simple and well understood process seems to work. Simple freshman physics – Newton’s first law of motion – explains the gravitational dynamics of the first black holes detected by LIGO.”
The coalescence of 2 black holes is a very violent and exotic event. Rasio and his team used models of globular clusters – spherical collections of up to a million densely packed stars, common in the universe – to demonstrate that a typical cluster can very naturally create a binary black hole that will merge and form one larger black hole. Their powerful computer model can predict how many merging binary black holes LIGO might detect: potentially 100 forged in the cores of these dense star clusters per year. The model also shows where in the universe the binary black holes are, how long ago they merged and the masses of each black hole.
Rodriguez and colleagues used 52 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. For the study, the team used a parallel computing code for modeling star clusters.
Advanced LIGO (Laser Interferometer Gravitational-Wave Observatory) 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. http://www.northwestern.edu/newscenter/stories/2016/06/mosh-pit-star-clusters-black-holes.html
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