Abstract

Galaxies are “ecosystems” where energy flows and material cycles are self-regulated in a pattern referred to as “baryon cycle”. When inflows of gas trigger star formation, ionizing radiation is emitted into the interstellar medium (ISM) and Supernovae II feedback also releases chemical elements into the ISM. These processes modify the composition and structure of the ISM and can lead to the escape of ionizing radiation and Lyman alpha photons. In this talk, I will investigate two specific aspects of the baryon cycle. I will show the value of chemical abundances and in particular of the carbon/oxygen abundance to trace the early stages of the galaxy star formation histories.I will also discuss the connection between the structure of the ISM, LyC escape fraction and the Lya emission. I will present new analytical models that describe how the Lyman alpha equivalent width varies as a function of the ISM structure and content.