The detection of gravitational waves with Advanced LIGO and Advanced Virgo has enabled novel tests of general relativity, including direct study of the polarization of gravitational waves. While general relativity allows for only two tensor gravitational-wave polarizations, general metric theories can additionally predict two vector and two scalar polarizations. The polarization of gravitational waves is encoded in the spectral shape of the stochastic gravitational-wave background, formed by the superposition of cosmological and individually unresolved astrophysical sources. Using data recorded by Advanced LIGO during its first observing run, we search for a stochastic background of generically polarized gravitational waves. We find no evidence for a background of any polarization, and place the first direct bounds on the contributions of vector and scalar polarizations to the stochastic background. Under log-uniform priors for the energy in each polarization, we limit the energy densities of tensor, vector, and scalar modes at 95% credibility to Ω0T < 5.58 x 10-8, Ω0V < 6.35 x 10-8, and Ω0S < 1.08 x 10-7 at a reference frequency f0 = 25 Hz.



Keywords and Phrases

Gravitational effects; Polarization; Relativity; Stochastic systems; Tensors; Testing; Vectors; Astrophysical sources; Energy density; General Relativity; Reference frequency; Scalar modes; Spectral shapes; Gravity waves

International Standard Serial Number (ISSN)


Document Type

Article - Journal

Document Version

Final Version

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© 2018 American Physical Society (APS), All rights reserved.

Publication Date

01 May 2018

Included in

Physics Commons