Stochastic gravitational wave background from supernovae in massive scalar-tensor gravity

In massive scalar-tensor gravity, core-collapse supernovae are strong sources of scalar-polarized gravitational waves. These can be detectable out to large distances. The dispersive nature of the propagation of waves in the massive scalar field implies that the gravitational wave signals are long-lived, and many such signals can overlap to form a stochastic background. Using different models for the population of supernova events in the nearby universe, we compute predictions for the energy density in the stochastic scalar-polarized gravitational wave background from core-collapse events in massive scalartensor gravity for theory parameters that facilitate strong scalarization. The resulting energy density is below the current constraints on a Gaussian stochastic gravitational wave background but large enough to be detectable with the current generation of detectors when they reach design sensitivity, indicating that it will soon be possible to place new constraints on the parameter space of massive scalar-tensor gravity.