Scientists detect new Gravitational Waves
An international team of scientists including researchers from Monash University and the ARC Centre of Excellence for Gravitational Wave Discovery (OzGrav) has just released the latest results from the National Science Foundation’s LIGO (Laser Interferometer Gravitational-Wave Observatory) and the European-based Virgo gravitational-wave detector.
The data, presented in a series of journal publications published today showcases ripples in spacetime (called gravitational waves) from a total of 10 binary black hole mergers. Six of the black hole merger events had been reported before, while four are newly announced.
“We are building up a black hole catalogue,” said Dr Paul Lasky, LIGO member and Senior Lecturer at the Monash School of Physics and Astronomy.
“Gravitational-wave astronomy is coming into its own.”
“We can use these Gravitational Waves from black holes to learn about all kinds of things, like the fate of massive stars,” said Associate Professor Eric Thrane, a fellow LIGO member from the Monash School of Physics and Astronomy.
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.
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 five billion years ago, an equivalent energy of almost five solar masses was converted into gravitational radiation.
Author, PhD candidate Colm Talbot from OzGrav and Monash University, in a separate paper describes how the detection of these new black holes will assist in understanding the Universe’s entire population of black holes.
“Each of these black holes formed from huge stars which died in violent explosions called supernovae,” he said.
“By studying these black holes, we act as black hole archaeologists to learn how these cosmic giants die.”
The ARC Centre of Excellence for Gravitational Wave Discovery (OzGrav) is funded by the Australian Government through the Australian Research Council Centres of Excellence funding scheme. OzGrav is a partnership between Swinburne University of Technology (host of OzGrav headquarters), the Australian National University, Monash University, University of Adelaide, University of Melbourne, and University of Western Australia, along with other collaborating organisations in Australia and overseas.
LIGO is funded by NSF and operated by Caltech and MIT, which conceived of LIGO and led the Initial and Advanced LIGO projects. Financial support for the Advanced LIGO project was led by the NSF with Germany (Max Planck Society), the U.K. (Science and Technology Facilities Council) and Australia (Australian Research Council-OzGrav) making significant commitments and contributions to the project. More than 1,200 scientists from around the world participate in the effort through the LIGO Scientific Collaboration, which includes the GEO Collaboration. A list of additional partners is available at http://ligo.org/partners.php.
The Virgo collaboration consists of more than 300 physicists and engineers belonging to 28 different European research groups: six from Centre National de la Recherche Scientifique (CNRS) in France; 11 from the Istituto Nazionale di Fisica Nucleare (INFN) in Italy; two in the Netherlands with Nikhef; the MTA Wigner RCP in Hungary; the POLGRAW group in Poland; Spain with IFAE and the Universities of Valencia and Barcelona; two in Belgium with the Universities of Liege and Louvain; Jena University in Germany; and the European Gravitational Observatory (EGO), the laboratory hosting the Virgo detector near Pisa in Italy, funded by CNRS, INFN, and Nikhef. A list of the Virgo Collaboration can be found at http://public.virgo-gw.eu/the-virgo-collaboration/. More information is available on the Virgo website at www.virgo-gw.eu.
Paper: “GWTC-1: A Gravitational-Wave Transient Catalog of Compact Binary Mergers Observed by LIGO and Virgo during the First and Second Observing Runs”
Paper: “Binary Black Hole Population Properties Inferred from the First and Second Observing Runs of Advanced LIGO and Advanced Virgo”
Papers available on the arXiv and the LIGO DCC, https://dcc.ligo.org/
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