Nav: Home

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

May 11, 2018

EVANSTON, Ill. --- 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 hole binaries will be detectable by LISA in our neighboring galaxy of Andromeda and another 80 in nearby Virgo.

Before the first detection of gravitational waves by LIGO, as the twin detectors were being built in the United States, astrophysicists around the world worked for decades on theoretical predictions of what astrophysical phenomena LIGO would observe. That is what the Northwestern theoretical astrophysicists are doing in this new study, but this time for LISA, which is being built by the European Space Agency with contributions from NASA.

"We do our computer simulations and analysis at the same time our colleagues are bending metal and building spaceships, so that when LISA finally flies, we're all ready at the same time," said Shane L. Larson, associate director of CIERA and an author of the study. "This study is helping us understand what science is going to be contained in the LISA data."

A globular cluster is a spherical structure of hundreds of thousands to millions of stars, gravitationally bound together. The clusters are some of the oldest populations of stars in the galaxy and are efficient factories of compact object binaries.

The Northwestern research team had numerous advantages in conducting this study. Over the past two decades, Frederic A. Rasio and his group have developed a powerful computational tool -- one of the best in the world -- to realistically model globular clusters. Rasio, the Joseph Cummings Professor in Northwestern's department of physics and astronomy, is the senior author of the study.

The researchers used more than a hundred fully evolved globular cluster models with properties similar to those of the observed globular clusters in the Milky Way. The models, which were all created at CIERA, were run on Quest, Northwestern's supercomputer cluster. This powerful resource can evolve the full 12 billion years of a globular cluster's life in a matter of days.
NASA (ATP grant NNX14AP92G) and the National Science Foundation (grant AST-1716762) supported the research.

Other authors of the paper include Sourav Chatterjee and Katelyn Breivik, both of Northwestern and CIERA, and Carl L. Rodriguez, of the MIT-Kavli Institute for Astrophysics and Space Research.

(Source contacts: Kyle Kremer at and Shane Larson at 847-467-4305 or

Northwestern University

Related Black Hole Articles:

Scientists make waves with black hole research
Scientists at the University of Nottingham have made a significant leap forward in understanding the workings of one of the mysteries of the universe.
Collapsing star gives birth to a black hole
Astronomers have watched as a massive, dying star was likely reborn as a black hole.
When helium behaves like a black hole
A team of scientists has discovered that a law controlling the bizarre behavior of black holes out in space -- is also true for cold helium atoms that can be studied in laboratories.
Star in closest orbit ever seen around black hole
Astronomers have found evidence of a star that whips around a likely black hole twice an hour.
Tail of stray black hole hiding in the Milky Way
By analyzing the gas motion of an extraordinarily fast-moving cosmic cloud in a corner of the Milky Way, Astronomers found hints of a wandering black hole hidden in the cloud.
Hubble gazes into a black hole of puzzling lightness
The beautiful spiral galaxy visible in the center of the image is known as RX J1140.1+0307, a galaxy in the Virgo constellation imaged by the NASA/ESA Hubble Space Telescope, and it presents an interesting puzzle.
Clandestine black hole may represent new population
Astronomers have combined data from NASA's Chandra X-ray Observatory, the Hubble Space Telescope and the National Science Foundation's Karl G.
When will a neutron star collapse to a black hole?
Astrophysicists from Goethe-University Frankfurt have found a simple formula for the maximum mass of a rotating neutron star and hence answered a question that had been open for decades.
Behemoth black hole found in an unlikely place
Astronomers have uncovered a near-record breaking supermassive black hole, weighing 17 billion suns, in an unlikely place: in the center of a galaxy in a sparsely populated area of the universe.
Behemoth black hole found in an unlikely place
Astronomers have uncovered one of the biggest supermassive black holes, with the mass of 17 billion Suns, in an unlikely place: the centre of a galaxy that lies in a quiet backwater of the Universe.

Related Black Hole Reading:

Black Hole (Pantheon Graphic Library)
by Charles Burns (Author)

Death by Black Hole: And Other Cosmic Quandaries
by Neil deGrasse Tyson (Author)

The Little Book of Black Holes (Science Essentials)
by Steven S. Gubser (Author), Frans Pretorius (Author)

Black Holes (A True Book)
by Ker Than (Author)

A Black Hole Is Not a Hole
by Carolyn Cinami DeCristofano (Author), Michael Carroll (Illustrator)

Black Hole: How an Idea Abandoned by Newtonians, Hated by Einstein, and Gambled On by Hawking Became Loved
by Marcia Bartusiak (Author)

Black Holes and Time Warps: Einstein's Outrageous Legacy (Commonwealth Fund Book Program)
by Kip S. Thorne (Author), Stephen Hawking (Foreword)

Black Holes: A Very Short Introduction (Very Short Introductions)
by Katherine Blundell (Author)

Black Hole Blues and Other Songs from Outer Space
by Janna Levin (Author)

Black Holes (Kindle Single)
by Bantam

Best Science Podcasts 2018

We have hand picked the best science podcasts for 2018. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

The Story Behind The Numbers
Is life today better than ever before? Does the data bear that out? This hour, TED speakers explore the stories we tell with numbers — and whether those stories portray the full picture. Guests include psychologist Steven Pinker, economists Tyler Cowen and Michael Green, journalist Hanna Rosin, and environmental activist Paul Gilding.
Now Playing: Science for the People

#487 Knitting in PEARL
This week we're discussing math and things made from yarn. We welcome mathematician Daina Taimina to the show to discuss her book "Crocheting Adventures with Hyperbolic Planes: Tactile Mathematics, Art and Craft for all to Explore", and how making geometric models that people can play with helps teach math. And we speak with research scientist Janelle Shane about her hobby of training neural networks to do things like name colours, come up with Halloween costume ideas, and generate knitting patterns: often with hilarious results. Related links: Crocheting the Hyperbolic Plane by Daina Taimina and David Henderson Daina's Hyperbolic Crochet blog...