LIGO and the opening of a unique observational window on the universe

Vassiliki Kalogera, Albert Lazzarini*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


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.

Original languageEnglish (US)
Pages (from-to)3017-3025
Number of pages9
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number12
StatePublished - Mar 21 2017


  • Black holes
  • Gravitational waves
  • LIGO

ASJC Scopus subject areas

  • General


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