Dozens of binaries from Milky Way’s globular clusters could be detectable by LISA

Northwestern Now: Summaries

EVANSTON – The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A string of detections — four more binary black holes and a pair of neutron stars — soon followed the Sept. 14, 2015, observation.Now, another detector is being built to crack this window wider open. This next-generation observatory, called LISA, is expected to be in space in 2034, and it will be sensitive to gravitational waves of a lower frequency than those detected by the Earth-bound Laser Interferometer Gravitational-Wave Observatory (LIGO).A new Northwestern University study predicts dozens of binaries (pairs of orbiting compact objects) in the globular clusters of the Milky Way will be detectable by LISA (Laser Interferometer Space Antenna). These binary sources would contain all combinations of black hole, neutron star and white dwarf components. Binaries formed from these star-dense clusters will have many different features from those binaries that formed in isolation, far from other stars.The study is the first to use realistic globular cluster models to make detailed predictions of LISA sources. “LISA Sources in Milky-Way Globular Clusters” was published today, May 11, by the journal Physical Review Letters.“LISA is sensitive to Milky Way systems and will expand the breadth of the gravitational wave spectrum, allowing us to explore different types of objects that aren’t observable with LIGO,” said Kyle Kremer, the paper’s first author, a Ph.D. student in physics and astronomy in Northwestern’s Weinberg College of Arts and Sciences and a member of a computational astrophysics research collaboration based in Northwestern’s Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA).In the Milky Way, 150 globular clusters have been observed so far. The Northwestern research team predicts one out of every three clusters will produce a LISA source. The study also predicts that approximately eight black …

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