Four new gravitational wave detections announced
(3 December 2018 - STFC) Four new gravitational wave detections announced today include the most massive and distant source ever observed.
The results are included in a new paper from the Laser Interferometer Gravitational-Wave Observatory (LIGO) and the VIRGO gravitational-wave detector, which presents analysis of 10 stellar-mass binary black hole mergers and one neutron star merger.
Professor Sheila Rowan is Director of the University of Glasgow’s Institute for Gravitational Research. Professor Rowan said: “This remarkable crop of detections show just how valuable gravitational wave astronomy is in developing our understanding of the universe.
(courtesy: Teresita Ramirez / Geoffrey Lovelace / SXS Collaboration / LIGO-Virgo Collaboration)
“In less than three years gravitational wave detections have given us direct evidence of the existence of black holes and binary neutron star collisions. Today we present a wealth of new data from LIGO and Virgo to stand alongside the ground-breaking discoveries already made during their initial observing runs. It took science a century to confirm Einstein’s prediction of the existence of gravitational waves, but the pace of our discoveries since then has been exhilarating, and we’re anticipating many more exciting detections to come.”
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 a 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 based on the dates on which they were detected.
The new event GW170729, detected in the second observing run on July 29, 2017, is the most massive and distant gravitational-wave source ever observed. In this coalescence, which happened roughly 5 billion years ago, an equivalent energy of almost five solar masses was converted into gravitational radiation.
Since the detectors first started operation in September 2015, the LIGO and Virgo Collaborations, which include the Universities of Birmingham, Cardiff and Glasgow and also the University of Strathclyde, have completed two observation runs. During these runs they have detected gravitational waves from a total of ten stellar-mass binary black hole mergers – compact objects likely formed by the gravitational collapse of massive stars. They have also detected one binary neutron star coalescence – generated by two neutron stars spiraling into each other.