GW170817: Implications for the Stochastic Gravitational-Wave Background from Compact Binary Coalescences

Abstract

The LIGO Scientific and Virgo Collaborations have announced the event GW170817, the first detection of gravitational waves from the coalescence of two neutron stars. The merger rate of binary neutron stars estimated from this event suggests that distant, unresolvable binary neutron stars create a significant astrophysical stochastic gravitational-wave background. The binary neutron star component will add to the contribution from binary black holes, increasing the amplitude of the total astrophysical background relative to previous expectations. In the Advanced LIGO-Virgo frequency band most sensitive to stochastic backgrounds (near 25 Hz), we predict a total astrophysical background with amplitude Ω_{GW}(f=25 Hz)=1.8_{-1.3}^{+2.7}×10^{-9} with 90% confidence, compared with Ω_{GW}(f=25 Hz)=1.1_{-0.7}^{+1.2}×10^{-9} from binary black holes alone. Assuming the most probable rate for compact binary mergers, we find that the total background may be detectable with a signal-to-noise-ratio of 3 after 40 months of total observation time, based on the expected timeline for Advanced LIGO and Virgo to reach their design sensitivity.

Measurement and subtraction of Schumann resonances at gravitational-wave interferometers

“…One potential method for detecting a SGWB is to use a network of ground-based, second-generation interferometric gravitational-wave detectors, which currently consists of Advanced LIGO [1] and Advanced Virgo [2]. A SGWB from compact binary coalescences is potentially detectable by the time second-generation detectors reach design sensitivity [3]. Backgrounds from pulsars, magnetars, core-collapse supernovae, and various physical processes in the early universe are all possible as well [4][5][6], but their expected amplitudes are not as well constrained as the expected background due to compact binary coalescences.…”

Optimal Search for an Astrophysical Gravitational-Wave Background

“…though our analysis can incorporate any suitable choice of π(ξ), informed, for instance, by expectations about the average time between binary black hole mergers [1].…”

“…Observations of gravitational waves from binary black hole mergers imply that stellar-mass black holes coalesce somewhere in the visible Universe every 223 +352 −115 s [1]. Binary neutron stars merge every 13 +49 −9 s [1]. The vast majority of these events are too distant to be individually resolved by the current generation of detectors.…”

“…A Gaussian background is characterized entirely by Ω gw (f ). The stochastic background from stellar-mass binary black holes is highly non-Gaussian; it is rare for different events to overlap in time [1] (within the advanced detector band). The stochastic backgrounds from binary neutron stars are quasi-Gaussian since the signals from individual events overlap in time [1].…”

“…The stochastic background from stellar-mass binary black holes is highly non-Gaussian; it is rare for different events to overlap in time [1] (within the advanced detector band). The stochastic backgrounds from binary neutron stars are quasi-Gaussian since the signals from individual events overlap in time [1]. We focus initially on the highly non-Gaussian background from stellar-mass binary black holes, but return below to consider quasi-Gaussian backgrounds from binary neutron stars.…”