B. P. Abbott, California Institute of TechnologyFollow
R. Abbott, California Institute of TechnologyFollow
T. D. Abbott, Louisiana State UniversityFollow
S. Abraham, Inter-University Centre for Astronomy and Astrophysics IndiaFollow
F. Acernese, Università degli Studi di SalernoFollow
K. Ackley, Monash UniversityFollow
C. Adams, LIGO LivingstonFollow
V. B. Adya, Max Planck Institute for Gravitational Physics (Albert Einstein Institute)Follow
C. Affeldt, Max Planck Institute for Gravitational Physics (Albert Einstein Institute)Follow
M. Agathos, University of CambridgeFollow
K. Agatsuma, University of BirminghamFollow
N. Aggarwal, LIGO, Massachusetts Institute of TechnologyFollow
O. D. Aguiar, Instituto Nacional de Pesquisas EspaciaisFollow
L. Aiello, Gran Sasso Science InstituteFollow
A. Ain, Inter-University Centre for Astronomy and Astrophysics IndiaFollow
P. Ajith, Tata Institute of Fundamental Research, MumbaiFollow
G. Allen, University of Illinois Urbana-ChampaignFollow
A. Allocca, Università di PisaFollow
M. A. Aloy, Universitat de València
P. A. Altin, The Australian National UniversityFollow
A. Amato, CNRS Centre National de la Recherche ScientifiqueFollow
A. Ananyeva, California Institute of TechnologyFollow
S. B. Anderson, California Institute of TechnologyFollow
W. G. Anderson, University of Wisconsin-MilwaukeeFollow
S. V. Angelova, University of Strathclyde
S. Antier, Laboratoire de l'Accélérateur Linéaire
S. Appert, California Institute of Technology
K. Arai, California Institute of Technology
M. C. Araya, California Institute of Technology
J. S. Areeda, California State University, Fullerton
M. Arène, APC - AstroParticule et Cosmologie
N. Arnaud, Laboratoire de l'Accélérateur Linéaire
K. G. Arun, Chennai Mathematical Institute

Document Type

Article

Publication Date

9-4-2019

Abstract

The stochastic gravitational-wave background is a superposition of sources that are either too weak or too numerous to detect individually. In this study, we present the results from a cross-correlation analysis on data from Advanced LIGO's second observing run (O2), which we combine with the results of the first observing run (O1). We do not find evidence for a stochastic background, so we place upper limits on the normalized energy density in gravitational waves at the 95% credible level of ωGW<6.0×10-8 for a frequency-independent (flat) background and ωGW<4.8×10-8 at 25 Hz for a background of compact binary coalescences. The upper limit improves over the O1 result by a factor of 2.8. Additionally, we place upper limits on the energy density in an isotropic background of scalar- and vector-polarized gravitational waves, and we discuss the implication of these results for models of compact binaries and cosmic string backgrounds. Finally, we present a conservative estimate of the correlated broadband noise due to the magnetic Schumann resonances in O2, based on magnetometer measurements at both the LIGO Hanford and LIGO Livingston observatories. We find that correlated noise is well below the O2 sensitivity.

Publication Source (Journal or Book title)

Physical Review D

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