01 Feb 2021 — The LIGO, Virgo and KAGRA collaborations report new upper limits on the background of gravitational waves in the universe, in two papers recently submitted to the ArXiv. The two papers present analyses of data collected during the third observing run (O3) of the Advanced LIGO and Advanced Virgo detectors. This is the first time we have included data from the Virgo detector, in addition to the two LIGO instruments, in our searches for gravitational-wave backgrounds.
In the first paper, we present results from a generic search for the gravitational-wave background generated by different astrophysical and cosmological sources. In our second paper, we present results from a more targeted search for gravitational waves from cosmic strings: hypothetical one-dimensional objects which may have formed in the early universe.
Read more about both papers in the science summaries here and here.