TAPIR Seminar

Galactic winds are necessary to reduce the star formation rate in simulated galaxies in order to match observations. These outflows are so violent that they completely change the properties of the galaxy and its environment. I will show results from cosmological zoom-in simulations, part of the Feedback In Realistic Environments (FIRE) project, which includes a detailed implementation of stellar feedback. I will discuss observational probes of the gas flow into and out of galaxies. Gas discs which are kinematically misaligned with the stellar component are commonly observed in massive early-type galaxies. I will show that misaligned gas discs can persist for a long time, because of the addition of angular momentum from freshly accreted gas. Outflows enrich and heat the gas in galaxy haloes and thus change their X-ray properties. I will show how this depends on stellar mass and what the contribution of galactic outflows is to the total X-ray luminosity. Additionally, the distribution of metals, especially rapid neutron capture (r-process) elements formed in neutron star mergers, is greatly affected by feedback. For low-metallicity halo stars, our simulations predict a wide range of stellar r-process abundance ratios, consistent with observations. I will therefore argue that neutron star mergers could be the source of most of the r-process nuclei in the Universe.