Cosmology with Gravitational Wave Sirens
Gravitational wave (GW) sirens are a group of methods used to measure the expansion rate of the universe, and to test the nature of gravity on large scales. In this talk I’ll introduce the main categories of GW sirens — bright, dark, and spectral —explaining how they differ. I’ll explain how cosmologists have adapted to work around the lack of multi-messenger events since our one and only (to date!) bright siren, the binary neutron star merger GW170817.
We’ll take stock of where the current constraints from GW sirens stand. We’ll then explore how we can enhance these constraints by using our knowledge of the cosmic web, and its additional sensitivity to the laws of gravity.
Finally, we’ll look at what lies ahead in the short-term and long-term for cosmology using gravitational waves. With tens of thousands of GW sources in hand, will we ultimately use GWs as ‘just another tracer’ of the cosmic web, similar to galaxies?