Speaker
Description
We are now routinely detecting gravitational waves (GW) emitted by merging black holes and neutron stars. Those are the afterlives of massive stars that formed all across the Universe - at different times and with different metallicities (i.e. abundances of elements heavier than helium).
Birth metallicity plays an important role in the evolution of massive stars.
Consequently, the population properties of mergers are sensitive to the metallicity dependent cosmic star formation history.
In particular, within the isolated merger formation scenarios (the focus of my talk), a strong low metallicity preference of the formation of mergers involving black holes was found. I will disscuss its origin and consequences.
Most importantly, the uncertainty in the amount of star formation happening at low metallicity cannot be ignored in the models and makes the interpretation of current GW observations challenging.
Factors that dominate this uncertainty 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 means that future GW observations can serve as a complementary tool to study chemical evolution of galaxies.
