Improved limits on a stochastic gravitational-wave background and its anisotropies from Advanced LIGO O1 and O2 runs

2019/07/24 by Arianna Renzini, Carlo Contaldi · 1 citation
Physics and Astronomy · #astro-ph.CO #astro-ph.IM #gr-qc

paper · pdf · doi:10.1103/physrevd.100.063527

published as Phys. Rev. D 100, 063527 (2019) · 9 pages, 8 figures

arxiv created 2019/07/24 · arxiv updated 2019/09/25

Abstract

We integrate the entire, publicly available, Advanced LIGO (ALIGO) data set to obtain maximum-likelihood constraint maps of the Stochastic Gravitational-Wave Background (SGWB). From these we derive limits on the energy density of the stochastic background Ω_{\rm GW}, and its anisotropy. We find 95% confident limits Ω_{\rm GW} < 5.2× 10^-8 at 50 Hz for a spectral index α=2/3 consistent with a stochastic background due to inspiral events and Ω_{\rm GW} < 3.2× 10^-7 for a scale (frequency) invariant spectrum. We also report upper limits on the angular power spectra C_ℓ for three broadband integrations of the data. Finally we present an estimate where we integrate the data into ten separate spectral bins as a first attempt to carry out a model-independent estimate the SGWB and its anisotropies.

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