Tag: KAGRA

Categories
GeekWire

Gravitational-wave sleuths look for more cosmic crashes

A specialist checks the alignment of a test beam at the Laser Interferometer Gravitational-wave Observatory. (NSF Photo)

After three years of upgrading and waiting, due in part to the coronavirus pandemic, the Laser Interferometer Gravitational-wave Observatory has officially resumed its hunt for the signatures of crashing black holes and neutron stars.

“Our LIGO teams have worked through hardship during the past two-plus years to be ready for this moment, and we are indeed ready,” Caltech physicist Albert Lazzarini, the deputy director of the LIGO Laboratory, said in a news release.

Lazzarini said the engineering tests leading up to today’s official start of Observing Run 4, or O4, have already revealed a number of candidate events that have been shared with the astronomical community.

“Most of these involve black hole binary systems, although one may include a neutron star,” he said. “The rates appear to be consistent with expectations.”

One such event, called S230518h, was detected last week. Researchers say that if they can confirm the data, the event was most likely caused by the merger of a faraway black hole and a neutron star.

The twin LIGO gravitational-wave detectors at Hanford, Wash., and Livingston, La., will be joined for O4 by the Virgo detector in Italy as well as the KAGRA observatory in Japan. Virgo is scheduled to take part in the run starting later this year. KAGRA will parallel LIGO’s observations for the next month, take a break for some upgrades, and then rejoin the run.

Get the full story on GeekWire
Categories
Cosmic Space

Confirmed! Black holes and neutron stars collide

Artwork shows a black hole and a neutron star circling toward a merger. (Credit: Carl Knox / OzGrav / Swinburne U.)

Gravitational-wave astronomers are confident that they’ve filled out their repertoire of cataclysmic collisions, thanks to the detection of two cosmic crashes that each involved a black hole and a neutron star.

Over the past five years, astronomers have used the twin LIGO gravitational-wave detectors in Washington state and Louisiana, plus the Virgo detector in Italy, to pick up signals from more than 50 violent mergers of black holes with black holes, or neutron stars with neutron stars.

In 2019, the astronomers picked up readings from two events that might have been caused by hot black-hole-on-neutron-star action. But one of those detections, on April 26, 2019, could plausibly have been nothing more than noise in the detectors. The other event, on Aug. 14, 2019, involved a crash between a black hole and an object that was either the heaviest known neutron star or the lightest known black hole. The gravitational-wave hunters couldn’t say definitively which.

In contrast, astronomers leave little doubt that the gravitational waves sparked by two separate events in January 2020 were thrown off by the merger of a black hole and a neutron star. They lay out their evidence in a paper published today by The Astrophysical Journal Letters.

“With this new discovery of neutron star-black hole mergers outside our galaxy, we have found the missing type of binary. We can finally begin to understand how many of these systems exist, how often they merge, and why we have not yet seen examples in the Milky Way,” Astrid Lamberts, a member of the Virgo collaboration who works at the Observatoire de la Côte d’Azur in France, said in a news release.

There’s still some mystery surrounding the detections.

Continue reading “Confirmed! Black holes and neutron stars collide”
Categories
GeekWire

Japan joins the global gravitational wave hunt

An illustration provides a cutaway view of the underground KAGRA gravitational-wave detector in Japan. (ICRR / Univ. of Tokyo Illustration)

Japan’s Kamioka Gravitational-Wave Detector, or KAGRA, is due to start teaming up with similar detectors in Washington state, Louisiana and Italy in December, boosting scientists’ ability to triangulate on the origins of cataclysmic cosmic events such as black hole smash-ups.

Representatives of KAGRA, the U.S.-based Laser Interferometer Gravitational-Wave Observatory (LIGO) and Europe’s Virgo detector signed a memorandum of agreement today in Toyama, Japan, to confirm their collaboration. The agreement includes plans for joint observations and data sharing.

“This is a great example of international scientific cooperation,” Caltech’s David Reitze, executive director of the LIGO Laboratory, said in a news release. “Having KAGRA join our network of gravitational-wave observatories will significantly enhance the science in the coming decade.”

Nobel-winning physicist Takaaki Kajita, principal investigator of the KAGRA project, said “we are looking forward to joining the network of gravitational-wave observations later this year.”

Get the full story on GeekWire.

Exit mobile version