2020-12-04 11:00  P5A-1

Gravitational Waves and their Tidal Forces in Cosmological Spacetimes

Yen-Wei Liu

Despite being well-studied in the asymptotically-flat spacetime, the propagation of gravitational waves (GWs), generated by a distant isolated astrophysical source, has not been much addressed in a cosmological background until very recently. As most of the LIGO/Virgo's confirmed events have seen such non-trivial reshifts from their progenitors, it becomes more desirable to investigate these cosmological GWs from first principles. In particular, the scalar acoustic waves, associated with the scalar portion of the metric, have been shown to potentially coexist with their usual spin-2 counterparts in a relativistic fluid-driven cosmology. I will discuss these new features in some cosmological scenarios of interest.