HEP Colloquia 2025

by Matteo Schulz (Istituto Nazionale di Fisica Nucleare)

Wednesday 21 May 2025, 15:00 → 15:30 Europe/Rome

Sala Consiliare (Department of Physics)

Cosmology with Gravitational Waves x Neutral Hydrogen Cross-Correlation with Future Observatories

Despite the success of the Lambda-CDM model in describing the Universe, tensions in cosmological measurements are calling for new independent cosmological probes. Among the most promising are gravitational waves (GWs) and neutral hydrogen (HI).
We explore the potential of cross-correlation between GWs and 21 cm intensity mapping (IM) from neutral hydrogen emission, focusing on its role in view of future high-precision observatories, specifically Einstein Telescope (ET) and the Square Kilometer Array Observatory (SKAO).
We model the large scale structure evolution by making use of 3D lightcones of the dark matter density distribution up to redshift z ~ 3 from both linear perturbation theory and N-body simulations.
Assuming that GW and HI are different tracers of the same underlying density field, we infer cosmological parameters from both the angular power spectrum (auto-correlation) and the angular cross-power spectrum (cross-correlation) of these probes.
We examine synergies between future GW and HI experiments and evaluate their improvement on standard sirens measurements, thanks to increased sensitivity and high-redshift coverage, allowing to constrain cosmological parameters to a level comparable to that of well-established alternative probes, such as Type Ia Supernovae and the Cosmic Microwave Background.