Scientists See Black Hole Swallowing a Neuton Star

The LIGO-Virgo gravitational wave detector has discovered an event of a type that could be the result of the collision between a black hole and a neutron star, a phenomenon never before seen by astronomers.

A first-of-its-king event

Researchers spotted the collision between a neutron star and a black home on April 26.

“The universe is keeping us on our toes,” says Patrick Brady, spokesperson for the LIGO Scientific Collaboration and a professor of physics at the University of Wisconsin-Milwaukee.

“We’re especially curious about the April 26 candidate. Unfortunately, the signal is rather weak. It’s like listening to somebody whisper a word in a busy café; it can be difficult to make out the word or even to be sure that the person whispered at all. It will take some time to reach a conclusion about this candidate.”

Referred to as S190426c, the collision is estimated to have taken place roughly 1.2 billion light-years away.


LIGO and Virgo team members estimate that the candidate gravitational signal referred to as S190426c originated from the region outlined on the sky map. Image: LIGO/Virgo/NASA/Leo Singer (Milky Way image: Axel Mellinger)

“NSF’s LIGO, in collaboration with Virgo, has opened up the universe to future generations of scientists,” says NSF Director France Córdova.

“Once again, we have witnessed the remarkable phenomenon of a neutron star merger, followed up closely by another possible merger of collapsed stars. With these new discoveries, we see the LIGO-Virgo collaborations realizing their potential of regularly producing discoveries that were once impossible. The data from these discoveries and others sure to follow will help the scientific community revolutionize our understanding of the invisible universe.”

Ligo and Virgo

The revolutionary find came only a few weeks after researchers tuned LIGO and Virgo back on.

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Both twin detectors of LIFO—one in Washington and another one in Louisiana—as well as Virgo, at the European Gravitational Observatory (EGO) in Italy, resumed operations on April 1, after the systems went through a series of upgrades to increase their sensitivity in detecting gravitational waves, aka ripples in space and time.

The upgrade will allow both instruments to survey a much larger part of the universe and also help detect events like when neutron stars collide with black holes.

“Joining human forces and instruments across the LIGO and Virgo collaborations has been once again the recipe of an incomparable scientific month, and the current observing run will comprise 11 more months,” says Giovanni Prodi, the Virgo Data Analysis Coordinator, at the University of Trento.