LIGO/Virgo: Four New Gravitational-Wave Detections

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LIGO/Virgo: Four New Gravitational-Wave Detections

Post by bystander » Mon Dec 03, 2018 6:48 pm

LIGO and Virgo Announce Four New Detections
LIGO Scientific Collaboration | Virgo Collaboration | 2018 Dec 03

The observatories are also releasing their first catalog of gravitational-wave events

On Saturday, December 1, scientists attending the Gravitational Wave Physics and Astronomy Workshop in College Park, Maryland, presented new results from the National Science Foundation's LIGO (Laser Interferometer Gravitational-Wave Observatory) and the European- based VIRGO gravitational-wave detector regarding their searches for coalescing cosmic objects, such as pairs of black holes and pairs of neutron stars. The LIGO and Virgo collaborations have now confidently detected gravitational waves from a total of 10 stellar-mass binary black hole mergers and one merger of neutron stars, which are the dense, spherical remains of stellar explosions. Six of the black hole merger events had been reported before, while four are newly announced.

From September 12, 2015, to January 19, 2016, during the first LIGO observing run since undergoing upgrades in a program called Advanced LIGO, gravitational waves from three binary black hole mergers were detected. The second observing run, which lasted from November 30, 2016, to August 25, 2017, yielded one binary neutron star merger and seven additional binary black hole mergers, including the four new gravitational-wave events being reported now. The new events are known as GW170729, GW170809, GW170818, and GW170823, in reference to the dates they were detected.

All of the events are included in a new catalog, also released Saturday, with some of the events breaking records. ...

LIGO & VIRGO Announce Four New Gravitational-Wave Detections
Albert Einstein Institute | Max Planck Institute for Gravitational Physics | 2018 Dec 03

Gravitational Waves Shed Light on Population of Black Holes
Northwestern University | 2018 Dec 03

Four New Gravitational Wave Events from Black Hole Mergers
University of Maryland | CMNS | 2018 Dec 03

Scientists Detect Biggest Known Black-Hole Collision
Australian National University | 2018 Dec 03

Four New Gravitational Wave Detections Announced
Science & Technology Facilities Council, UK | 2018 Dec 03

GWTC-1: A Gravitational-Wave Transient Catalog of Compact Binary Mergers Observed by LIGO and
Virgo during the First and Second Observing Runs
~ LIGO Scientific Collaboration, Virgo Collaboration Binary Black Hole Population Properties Inferred from the First and Second Observing Runs
of Advanced LIGO and Advanced Virgo
~ LIGO Scientific Collaboration, Virgo Collaboration
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Re: LIGO/Virgo: Four New Gravitational-Wave Detections

Post by neufer » Tue Dec 04, 2018 4:02 am wrote:
<<The Kamioka Gravitational Wave Detector (KAGRA) is a project of the gravitational wave studies group at the Institute for Cosmic Ray Research (ICRR) of the University of Tokyo. KAGRA has two arms, 3 km long, which form a laser interferometric gravitational wave detector. KAGRA will detect gravitational waves from binary neutron star mergers at up to 240 Mpc away [6 times further than the LIGO/Virgo observed GW170817] with a signal to noise ratio of 10. The expected number of detectable events in a year is two or three. To achieve the required sensitivity, the existing state of the art techniques as used by LIGO and VIRGO (low-frequency vibration-isolation system, high-power laser system, Fabry-Pérot cavities, resonant side band extraction method, and so on) will be extended with an underground location, cryogenic mirrors, and a suspension point interferometer. Initial operation ("iKAGRA") with room-temperature test masses was hoped to begin in December 2015. The first operation of the interferometer happened in March 2016. The "baseline" planned cryogenic operation ("bKAGRA") will follow in 2019.>>
Art Neuendorffer