Abbott, B. P.Davies, G. S.LIGO Scientific Collaboration and Virgo Collaboration2017-04-052017-04-05Abbott, BP., et al., (LIGO Scientific Collaboration and Virgo Collaboration). (2017) Upper limits on the stochastic gravitational-wave background from Advanced LIGO’s first observing run. Physical Review Letters, Volume 118, Issue 12, 2017, Article number 121101http://dspace.lib.cranfield.ac.uk/handle/1826/11712https://doi.org/10.1103/PhysRevLett.118.121101A wide variety of astrophysical and cosmological sources are expected to contribute to a stochastic gravitational-wave background. Following the observations of GW150914 and GW151226, the rate and mass of coalescing binary black holes appear to be greater than many previous expectations. As a result, the stochastic background from unresolved compact binary coalescences is expected to be particularly loud. We perform a search for the isotropic stochastic gravitational-wave background using data from Advanced Laser Interferometer Gravitational Wave Observatory’s (aLIGO) first observing run. The data display no evidence of a stochastic gravitational-wave signal. We constrain the dimensionless energy density of gravitational waves to be Ω 0 < 1.7 × 10 − 7 with 95% confidence, assuming a flat energy density spectrum in the most sensitive part of the LIGO band (20–86 Hz). This is a factor of ∼ 33 times more sensitive than previous measurements. We also constrain arbitrary power-law spectra. Finally, we investigate the implications of this search for the background of binary black holes using an astrophysical model for the background.© 2017 American Physical Society. This is the publisher Version of Record Manuscript. Please refer to any applicable publisher terms of use.Article12110111812