LIGO and the opening of a unique observational window on the universe
A unique window on the universe opened on September 14, 2015, with direct detection of gravitational waves by the Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO) detectors. This event culminated a half-century effort around the globe to develop terrestrial detectors of adequate sensitivity to achieve this goal. It also happened appropriately only a few months before the centennial of Einstein's final paper introducing the general theory of relativity. This detection provided the surprising discovery of a coalescing pair of "heavy" black holes (more massive than ≃ 25 M_๏) leading to the formation of a spinning ≃ 62 solar mass black hole. One more binary black-hole detection and a significant candidate event demonstrated that a population of such merging binaries is formed in nature with a broad mass spectrum. This unique observational sample has already provided concrete measurements on the coalescence rates and has allowed us to test the theory of general relativity in the strong-field regime. As this nascent field of gravitational-wave astrophysics is emerging we are looking forward to the detection of binary mergers involving neutron stars and their electromagnetic counterparts, as well as continuous-wave sources, supernovae, a stochastic confusion background of compact-object mergers, known sources detected in unexpected ways, and completely unknown sources.
© 2017 National Academy of Sciences. Edited by Neta A. Bahcall, Princeton University, Princeton, NJ, and approved February 8, 2017 (received for review November 14, 2016) Published online before print March 10, 2017. We have presented a summary of the findings from the first aLIGO observational run. Much of the information reviewed here appears in a body of literature, referenced herein, that the LIGO Scientific Collaboration and Virgo Collaboration published throughout 2016. This body of work was the product of our many dedicated colleagues who contributed to the overall understanding of what nature is telling us with our first detections. We also gratefully acknowledge the support of the US National Science Foundation (NSF) for the construction and operation of the LIGO Laboratory and Advanced LIGO, as well as the Science and Technology Facilities Council (STFC) of the United Kingdom, the Max-Planck Society, and the State of Niedersachsen, Germany, for support of the construction of Advanced LIGO and construction and operation of the GEO600 detector. Additional support for Advanced LIGO was provided by the Australian Research Council. We gratefully acknowledge the Italian Istituto Nazionale di Fisica Nucleare (INFN), the French Centre National de la Recherche Scientifique (CNRS), and the Foundation for Fundamental Research on Matter supported by the Netherlands Organization for Scientific Research, for the construction and operation of the Virgo detector and for the creation and support of the European Gravitational-Wave Observatory (EGO) consortium. Further, we gratefully acknowledge research support from these agencies as well as by the Council of Scientific and Industrial Research of India; Department of Science and Technology, India; Science & Engineering Research Board, India; Ministry of Human Resource Development, India; the Spanish Ministerio de Economía y Competitividad; the Conselleria d'Economia i Competitivitat and Conselleria de Educació; Cultura i Universitats of the Govern de les Illes Balears; the National Science Center of Poland; the European Commission; the Royal Society; the Scottish Funding Council; the Scottish Universities Physics Alliance; the Hungarian Scientific Research Fund; the Lyon Institute of Origins; the National Research Foundation of Korea; Industry Canada and the Province of Ontario through the Ministry of Economic Development and Innovation, the Natural Sciences and Engineering Research Council of Canada; the Canadian Institute for Advanced Research; the Brazilian Ministry of Science, Technology, and Innovation; the Russian Foundation for Basic Research; the Leverhulme Trust; the Research Corporation; Ministry of Science and Technology, Taiwan; and the Kavli Foundation. Finally, we gratefully acknowledge the support of the NSF, STFC, MPS, INFN, CNRS, and the State of Niedersachsen, Germany, for provision of computational resources. V.K. and A.L. contributed equally to this work. Author contributions: V.K. and A.L. wrote the paper. The authors declare no conflict of interest. This article is a PNAS Direct Submission.
Published - PNAS-2017-Kalogera-3017-25.pdf