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CIERA Graduate Student Michael Zevin Research Featured in AAS Nova

“The dense, chaotic centers of star clusters may be a birthplace for binary pairs of black holes like those observed by the Laser Interferometer Gravitational-Wave Observatory (LIGO). A new study now explores how eccentric binaries might arise and merge in these extreme environments.

….Since the discovery of the first gravitational-wave signal in September 2015, LIGO and its European counterpart Virgo have detected nine more merging black-hole binaries. After a brief pause for upgrades, the detectors are slated to come back online in April with significantly improved sensitivities — promising many more detections to come.

Though the gravitational-wave signals provide a wealth of information about the pre-merger binaries, we haven’t yet been able to determine how these black-hole binaries formed in the first place. Did these pairs evolve in isolation? Or were they born from interactions in the dense centers of star clusters?

One overlooked piece of data might shed light on these questions in the future: eccentricity. Since black-hole binaries in isolation take a long time to merge, any initial eccentricity in the orbit will be damped by gravitational-wave emission by the time the merger happens. But what if the binary doesn’t evolve in isolation? Could we see an imprint of eccentricity on the gravitational-wave signal then?

A new study led by scientist Michael Zevin (Northwestern University and CIERA) explores one possible channel for eccentric mergers: chaotic interactions between multiple black-hole binaries in the centers of star clusters.”

Read the full AAS Nova article, “Merging Eccentric Pairs of Black Holes“, by Susanna Kohler.


Banner Image Credit: Carl Rodriguez/Northwestern Visualization (Justin Muir, Matt McCrory, Michael Lannum)