Romeel Dave (University of Arizona)

The Impact of Galactic Outflows Across Cosmic Scales

Feedback from supernova-driven winds is an important driver of galaxy evolution, particularly during the heydey of star formation in the universe. I will present new cosmological SPH simulations incorporating heuristic models of superwind feedback, and study their impact on the properties of galaxies and intergalactic gas during the heydey of galaxy formation at z~2-6. I will focus particularly on metal enrichment as a unique observational tracer of such outflows. Remarkably, by parameterizing the outflow properties of galaxies at those epochs based on what is seen in local observations of rare starbursts, it is possible to reproduce a wide range of galaxy and IGM metallicity observations. I will further show that such agreement is unique to a rather narrow class of outflow models. Our simulations yield new and non-conventional interpretations for several puzzling observations, such as the constancy of CIV absorption in the high-z IGM, and the low scatter, uniformity, and slow evolution of the galaxy mass-metallicity relation. Our results suggests a strong connection between galactic outflows from the reionization epoch until today, and offer promise that this major uncertainty in galaxy formation theory will soon be well-constrained.