Ongoing Searches for Stochastic Gravitational Wave Sources

The gravitational-wave background (GWB) is a superposition of many astrophysical and cosmological sources, such as unresolved compact binaries, cosmic strings, and phase transitions in the early Universe. The third observing run published by the LIGO, Virgo, and KAGRA Collaborations, placed the most stringent upper limits on the energy density of the GWB to date. I will present results from a fiducial model constructed using the latest observations from GWTC-2 to estimate the astrophysical background from compact binaries, showing that its detection is expected with further improvements of the network sensitivity. Finally, I will show the results of applying a Bayesian method to treat correlated magnetic noise in the O3 data — a potential source of contamination in the future runs — which will allow us to ensure that once a signal is detected, it is of the gravitational origin.