Cosmography with Next-Generation Gravitational Wave Detectors

Advancements in cosmology through next-generation (XG) ground-based gravitational wave (GW) observatories will bring in a paradigm shift. We explore the pivotal role that GW standard sirens will play in inferring cosmological parameters with XG observatories, not only achieving exquisite precision but also opening up unprecedented redshifts. We examine the merits and the systematic biases involved in GW standard sirens utilizing binary black holes, binary neutron stars, and neutron star-black hole mergers. Further, we estimate the precision of bright sirens, golden dark sirens, and spectral sirens for these binary coalescences and compare the abilities of various XG observatories (A(#), cosmic explorer, Einstein telescope, and their possible networks). When combining different sirens, we find sub-percent precision over more than 10 billion years of cosmic evolution for the Hubble expansion rate H(z). This work presents a broad view of opportunities to precisely measure the cosmic expansion rate, decipher the elusive dark energy and dark matter, and potentially discover new physics in the uncharted Universe with XG GW detectors.