What are the signatures of gravitational waves in non-homogeneous cosmologies?
PT-CERN Call 2021/1
Antonio da Silva
FCUL (Universidade de Lisboa)
IA - Instituto de Astrofísica e Ciências do Espaço
So far, gravitational waves have been described in the context of homogeneous and isotropic Friedmann-Lemaître-Robertson-Walker (FLRW) models. A more general class of non-homogeneous Lemaître-Tolman-Bondi (LTB) models may be a more natural and an observationally consistent alternative to the present homogeneous and isotropic paradigm. Predictions for gravitational waves from the early universe and from astrophysical sources are still missing for this class of models and are necessary for the preparation of the next ESA flagship missions for cosmology: LISA and Euclid. The main objective of this project is to develop the framework of GW generation in LTB, and build realistic simulations of the GW background based on it, using a combination of numerical and Machine Learning methodologies. The plan is to perform a detailed characterization of the properties of the GW signal that will be detected by future GW experiments for this class of models. We will also propose to explore the complementarity between GW and Electromagnetic (EM) surveys, combining several wavelengths in a multi-messenger approach, to identify cosmological signatures of LTB non-homogeneity in future datasets such as the forthcoming ESA/Euclid satellite data releases.