Speaker
Description
The universe is permeated by gravitational waves that originate from a diverse array of astrophysical and cosmological sources. These waves collectively form the stochastic gravitational wave background (SGWB), the characterization of which is a major goal for numerous planned and ongoing missions, such as LIGO, Virgo, NANOGrav, and LISA. The waves comprising the SGWB are absorbed by stars through their excitation of global quadrupolar oscillation modes. In this work, we analyze oscillation data from stars belonging to several different variability classes in order to probe the energy density of the SGWB across a broad range of frequencies. We use these stars to place an upper bound on the characteristic strain of the SGWB produced at late cosmic times in the $10^{-5} - 10^{-2}$ Hz spectral window, which corresponds to the waves generated by compact binaries and extreme mass ratio inspirals. Aside from measurements from solar system bodies, these constraints are the strongest probe in this window until the forthcoming LISA mission in the 2030s.
