A gravitational-wave standard siren measurement of the Hubble constant

Abstract

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.

Search for Post-merger Gravitational Waves from the Remnant of the Binary Neutron Star Merger GW170817

“…Supporting this hypothesis were electromagnetic counterparts observed across the spectrum (Abbott et al 2017b(Abbott et al , 2017c. Thanks to its relatively close proximity to Earth, with 90% credible intervals of -+ 40 14 8 Mpc as measured by the GW data analysis (Abbott et al 2017a) and -+ 43.8 6.9 2.9 Mpc as measured with electromagnetic observations (Abbott et al 2017d), GW170817 offers the first opportunity to study the nature of the remnant leftover from a binary NS merger using GW observations.…”

Optical properties of high-quality oxide coating materials used in gravitational-wave advanced detectors

“…First detections of gravitational waves have opened a new era on multi-messenger astronomy [1][2][3], leading to the determination of fundamental quantities such as the Hubble constant [4]. This remarkable result has been achieved thanks to the efforts dedicated to the development of highly sensitive interferometric gravitationalwave detectors (GWD) [5,6].…”

A multidimensional implementation of the Advanced Spectral neutrino Leakage scheme

“…For example, the 1.7s delay between the gravitational wave (GW) peak and the gammarays from an event detected by the Fermi satellite (Goldstein et al 2017) allowed to constrain the deviations of the GW propagation speed from the speed of light to 1 part in 10 15 (Abbott et al 2017c). The detection further allowed for an independent measure of the Hubble parameter (Abbott et al 2017b) as suggested by Schutz (1986). The GW signal was followed by emission all across the electromagnetic (EM) spectrum (e.g.…”