Bibcode
Abbott, B. P.; Abbott, R.; Abbott, T. D.; Acernese, F.; Ackley, K.; Adams, C.; Adams, T.; Addesso, P.; Adhikari, R. X.; Adya, V. B.; Affeldt, C.; Afrough, M.; Agarwal, B.; Agathos, M.; Agatsuma, K.; Aggarwal, N.; Aguiar, O. D.; Aiello, L.; Ain, A.; Ajith, P.; Allen, B.; Allen, G.; Allocca, A.; Altin, P. A.; Amato, A.; Ananyeva, A.; Anderson, S. B.; Anderson, W. G.; Angelova, S. V.; Antier, S.; Appert, S.; Arai, K.; Araya, M. C.; Areeda, J. S.; Arnaud, N.; Arun, K. G.; Ascenzi, S.; Ashton, G.; Ast, M.; Aston, S. M.; Astone, P.; Atallah, D. V.; Aufmuth, P.; Aulbert, C.; Aultoneal, K.; Austin, C.; Avila-Alvarez, A.; Babak, S.; Bacon, P.; Bader, M. K. M.; Bae, S.; Baker, P. T.; Baldaccini, F.; Ballardin, G.; Ballmer, S. W.; Banagiri, S.; Barayoga, J. C.; Barclay, S. E.; Barish, B. C.; Barker, D.; Barkett, K.; Barone, F.; Barr, B.; Barsotti, L.; Barsuglia, M.; Barta, D.; Bartlett, J.; Bartos, I.; Bassiri, R.; Basti, A.; Batch, J. C.; Bawaj, M.; Bayley, J. C.; Bazzan, M.; Bécsy, B.; Beer, C.; Bejger, M.; Belahcene, I.; Bell, A. S.; Berger, B. K.; Bergmann, G.; Bero, J. J.; Berry, C. P. L.; Bersanetti, D.; Bertolini, A.; Betzwieser, J.; Bhagwat, S.; Bhandare, R.; Bilenko, I. A.; Billingsley, G.; Billman, C. R.; Birch, J.; Birney, R.; Birnholtz, O.; Biscans, S.; Biscoveanu, S.; Bisht, A.; Bitossi, M.; Biwer, C.; Bizouard, M. A. et al.
Bibliographical reference
Nature, Volume 551, Issue 7678, pp. 85-88 (2017).
Advertised on:
11
2017
Journal
Citations
974
Refereed citations
810
Description
On 17 August 2017, the Advanced LIGO and Virgo detectors observed the
gravitational-wave event GW170817—a strong signal from the merger
of a binary neutron-star system. 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. This sky region was subsequently observed by
optical astronomy facilities, resulting in the identification 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’ (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’: 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, while being completely
independent of them. Additional standard siren measurements from future
gravitational-wave sources will enable the Hubble constant to be
constrained to high precision.