Weak gravitational lensing for studies of the mass-observable relation in galaxy clusters

• Grant number: 25/19543-1
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: January 01, 2026
• End date: April 30, 2028
• Field of knowledge: Physical Sciences and Mathematics - Astronomy - Extragalactic Astrophysics
• Principal Investigator: Eduardo Serra Cypriano
• Grantee: Isabel Bonomo Pederneiras Barbosa
• Host Institution: Instituto de Astronomia, Geofísica e Ciências Atmosféricas (IAG). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

This research project is focused on galaxy clusters in the context of surveys such as CODEX, J-PAS, and S-PLUS, projecting toward more ambitious surveys like LSST.Due to their privileged position at the top of the hierarchical structure formation process, clusters occupy an intersection between astrophysics and observational cosmology. Not only do these objects retain information about the Universe that formed them, including dark energy, in their amount and distribution, but they also act as cosmic laboratories where it is possible to study the properties of dark matter and its interactions with itself and with baryonic matter.In this project, we intend to use clusters to address the issue of the tension in the amplitude of matter fluctuations between the current Universe and that predicted from cosmic microwave background radiation from the distant Universe: the S8 tension. Data for this purpose comes from the CODEX catalog and the S-PLUS and J-PAS surveys. For the latter, a series of steps for this purpose is planned in the project: i) an optical detection of clusters, ii) determination of the gravitational shear field by the shape of distant galaxies, and iii) calibration of the optical mass-observable relation via weak gravitational lensing by stacking.This project also includes the continuation of recently completed projects. We will deepen our study of baryon physics in clusters and explore how these are affected by the mechanisms of heating and cooling of the intra-cluster plasma. This is done via scaling relations between mass and observed quantities with X-rays and microwaves, using data from CODEX and eROSITA DR1 survey. (AU)