A gravitational-wave standard siren measurement of the Hubble constant

Research output: Contribution to journalArticle

Authors

  • LIGO Scientific Collaboration
  • Virgo Collaboration
  • 1M2H Collaboration
  • Dark Energy Camera GW-EM Collaboration
  • DES Collaboration
  • DLT40 Collaboration
  • Las Cumbres Observatory Collaboration
  • The VINROUGE Collaboration
  • MASTER Collaboration
  • Matt Nicholl

External organisations

  • California Institute of Technology
  • Louisiana State University
  • Universita degli Studi di Salerno
  • Complesso Universitario di Monte S.Angelo
  • University of Florida
  • Monash University
  • LIGO Livingston Observatory
  • LAPP, Université de Savoie, CNRS/IN2P3
  • University of Sannio at Benevento
  • Max Planck Institute for Gravitational Physics (Albert Einstein Institute) Am Mühlenberg 1, D-14476 Potsdam, Germany
  • University of Mississippi
  • University of Illinois at Urbana-Champaign
  • University of Cambridge
  • Institution Nikhef National Institute for Subatomic Physics
  • Massachusetts Institute of Technology
  • Instituto Nacional de Pesquisas Espaciais
  • Facebook
  • Laboratori Nazionali del Gran Sasso
  • Inter-University Centre for Astronomy and Astrophysics India
  • Tata Institute of Fundamental Research
  • University of Wisconsin-Milwaukee, Milwaukee, Wisconsin 53201, USA
  • Institut für Gravitationsphysik (Albert-Einstein-Institut)
  • Università di Pisa
  • Sezione INFN di Pisa
  • The Australian National University
  • Domaine Scientifique de la Doua
  • University of the West of Scotland
  • IN2P3

Abstract

On 17 August 2017, the Advanced LIGO 1 and Virgo 2 detectors observed the gravitational-wave event GW170817-a strong signal from the merger of a binary neutron-star system 3 . Less than two seconds after the merger, a γ-ray burst (GRB 170817A) was detected within a region of the sky consistent with the LIGO-Virgo-derived location of the gravitational-wave source 4-6 . This sky region was subsequently observed by optical astronomy facilities 7 , resulting in the identification 8-13 of an optical transient signal within about ten arcseconds of the galaxy NGC 4993. This detection of GW170817 in both gravitational waves and electromagnetic waves represents the first 'multi-messenger' astronomical observation. Such observations enable GW170817 to be used as a 'standard siren' 14-18 (meaning that the absolute distance to the source can be determined directly from the gravitational-wave measurements) to measure the Hubble constant. This quantity represents the local expansion rate of the Universe, sets the overall scale of the Universe and is of fundamental importance to cosmology. Here we report a measurement of the Hubble constant that combines the distance to the source inferred purely from the gravitational-wave signal with the recession velocity inferred from measurements of the redshift using the electromagnetic data. In contrast to previous measurements, ours does not require the use of a cosmic 'distance ladder' 19 : the gravitational-wave analysis can be used to estimate the luminosity distance out to cosmological scales directly, without the use of intermediate astronomical distance measurements. We determine the Hubble constant to be about 70 kilometres per second per megaparsec. This value is consistent with existing measurements 20,21 , while being completely independent of them. Additional standard siren measurements from future gravitationalwave sources will enable the Hubble constant to be constrained to high precision.

Details

Original languageEnglish
Pages (from-to)85-88
JournalNature
Volume551
Issue number7678
Early online date16 Oct 2017
Publication statusPublished - 2 Nov 2017

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