Metallicity-dependent cosmic star formation history скачать в хорошем качестве

Metallicity-dependent cosmic star formation history

Martyna Chruslinska (MPA, Germany) Abstract: The chemical composition of material within galaxies changes over time as elements produced in stellar interiors are ejected and mixed with the surrounding medium. Increasing metallicity alters the physics and observable properties of both stars and galaxies. Oxygen and carbon determine gas cooling and the way gas is converted to stars. Iron-group elements regulate the opacity in stars, influencing their lives and deaths, ionizing radiation input and feedback on galactic scales. Transient events of stellar-origin (e.g. long GRBs, X-ray sources) show an intriguing preference for the formation in metal-poor environments. A strong low metallicity dependence is also predicted on theoretical grounds for black hole mergers - dominant sources of currently observable gravitational waves. To advance our understanding of such processes, it is necessary to quantify the metallicity-dependent cosmic star formation history (fSFR(Z,t)), particularly in the low metallicity regime. I will summarize recent efforts to determine fSFR(Z,t) and identify factors that dominate its uncertainty. Many of those factors are related to the properties of galaxies that are faint and distant (and therefore difficult to observe). The fact that they leave imprint on the properties of mergers as a function of cosmic time makes future gravitational wave observations a potential new tool for studying the chemical evolution of galaxies.