Special Talk

• Special Talks

  Speaker: Farhan Hasan (STScI)
  Title: Shaping Cosmic Ecosystems Through Baryon Cycling: Simulations, Observations, and the promise of the Roman Era
  Abstract: Galaxy evolution is governed by the exchange of baryons across cosmic ecosystems, from the interstellar medium to the cosmic web, yet how these flows shape galaxy gas content, star formation, and morphology remains unclear. I will address this question across the majority of cosmic time by combining observations with state-of-the-art simulations. First, I will present how galaxy cold gas content and star formation depend on the cosmic web environment at z<0.5 using ground-based HI and HST-based galaxy surveys. Tensions with cosmological simulations reveal questions about the competition between cold gas accretion and shock-heating/gas stripping due to cosmic filaments. At z>1, simulations predict a dramatic transition in how large-scale environments affect the star formation activity and morphological characteristics of galaxies. I will introduce a powerful "slime mold"-inspired method to characterize large-scale structures: applications to deep wide-field galaxy surveys from Roman will enable robust, novel mapping of the z>1 cosmic web. Finally, I will show how a JWST slitless spectroscopic survey is charting the mass-metallicity relation (MZR) - a fundamental tracer of the baryon cycle - at z~1.7-3.5. We constrain the MZR down to unprecedentedly low masses and show its statistical dependence on morphology at this epoch for the first time. These results highlight the role that accretion and outflows play in shaping galaxies. I will conclude with how Roman will enable a dramatic improvement in these statistics and revolutionize our understanding of the cosmic baryon cycle at the peak epoch of galaxy formation.