Dark sirens and large scale structure

• Grant number: 24/04044-7
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• Start date until: July 01, 2024
• End date until: June 30, 2025
• Field of knowledge: Physical Sciences and Mathematics - Astronomy - Extragalactic Astrophysics
• Principal Investigator: Riccardo Sturani
• Grantee: Isabela Santiago de Matos
• Supervisor: Tessa Baker
• Host Institution: Instituto de Física Teórica (IFT). Universidade Estadual Paulista (UNESP). Campus de São Paulo. São Paulo , SP, Brazil
• Institution abroad: University of Portsmouth, England
• Associated to the scholarship: 23/02330-0 - Standard sirens: black or bright?, BP.PD

Abstract

Gravitational waves (GWs) allow the investigation of the Universe at large scales through a new channel of observations. They are at the same time distance indicators and tracers of the underlying matter field. It has been demonstrated in recent literature that the use of standard sirens as new standard candles and in combination with various cosmological probes is a very promising strategy for measuring the Hubble constant $H_0$ and eventual deviations from the standard cosmological model. The broad goal of this project is to systematically develop state-of-the-art methods for extracting robust and precise information on the cosmological model, using current and future gravitational wave observations with (bright) or without (dark) electromagnetic counterparts. As for the duration of the BEPE project, we plan to investigate a new statistical method based on the angular cross-correlations of binary black-hole (BBH) mergers with galaxies (and other tracers), that is model-independent and that overcomes various limitations of the current main methods using galaxy catalogs. We expect to obtain a precise measurement of $H_0$ with this method by the time of third generation GW detectors, such as the Einstein Telescope, and future large-scale structure surveys. We propose to further develop the method, which is already under study by our group, to its full potential; then compare it with the existing dark siren methods, and apply it to the context of various extensions of $\Lambda$CDM, starting with the construction of accurate forecasts for the large number of BBHs observations ($\mathcal{O}(10^5)$) expected in the near future.