The evolution of the mass - X-ray luminosity relation in the CODEX galaxy cluster sample

• Ano de defesa: 2024
• Autor(a) principal: Barbosa, Isabel Bonomo Pederneiras
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Biblioteca Digitais de Teses e Dissertações da USP
• Palavras-chave em Português: Aglomerados de Galáxias; Bayesian statistics; Estatística Bayesiana; Galaxy cluster; Raios-X; X-ray
• Link de acesso: https://www.teses.usp.br/teses/disponiveis/14/14131/tde-26032024-191951/

Precise measurements of X-ray scaling relations in galaxy clusters are imperative to probe cosmology and to study baryonic processes in the intercluster medium. The functional form of the correlation between X-ray luminosity and the total mass of galaxy clusters is well established in the purely gravitational self-similar model (Kaiser 1986). However, deviations from this model become apparent when non-gravitational processes, such as radiative cooling and AGN feedback, exert influence, potentially leading to a temporal evolution of the M-Lx relation. Up until this work, precise calibration of the M-Lx relation and its evolution, employing weak lensing mass estimates and a consistent statistical methodology, was still lacking. Our calibration utilizes the COnstrain Dark Energy with X-ray clusters (CODEX) catalog, which was thoroughly constructed by adopting an X-ray and optical selection of clusters in the superposition area of Rosat All Sky Survey (RASS) and Sloan Digital Sky Survey (SDSS). We analyze 101 CODEX galaxy clusters for which we have weak lensing mass estimates. This method is a distinction of the project since it is sensitive to the entire matter of the cluster, with no assumptions needed for the system dynamics. By introducing a Bayesian hierarchical model for scaling relation analysis, we account for heteroscedastic measurement errors, intrinsic scatter, optical and X-ray selection functions, and the subsample\'s construction criteria. The CODEX weak-lensing sample is well fit by a power law in log space with a slope of 0.3 ± 0.05, which is significantly shallower than the self-similar prediction. We also report an evolution parameter of 1.54 ± 0.55, which is statistically significant to infer a positive evolution of the scaling relation. As we investigate these intriguing findings, we point out our distinctive statistical approach and our analysis focused on a high-mass cluster sample as potential factors. We also conjecture the effects of AGN feedback and a possible evolution bias due to a redshift dependence of the Lx distribution. We also note that, when compared with previous studies, our work was the first to further constrain the evolution parameter to errors below the measured value.