College of Science & Engineering
Energetic outflows driven by star formation in young galaxies are required by state-of-the-art galaxy formation models. Outflow can be probed by absorption line of metals as well as by observations of the Lyman alpha (Lya) emission line. Because Lya photons scatter resonantly in the neutral hydrogen gas (HI) of the interstellar medium, their emergent spectrum depends on the properties of the outflows. Hence, Lya escape and/or line profile shapes have been suggested as diagnostics for outflow velocity and/or HI column density. Likewise, the size and shape of the outflowing gas can be measured from Lya imaging. However, since Lya scatters resonantly, researchers do not understand how to combine these diagnostics into accurate constraints.
This group uses MSI to address the challenges with outflow measurements. They run simulations to track the radiative transport of Lya photons on gas distributions obtained both from simple analytical prescriptions as well as from full hydrodynamical simulations. The simulations will result in synthetic spectra that will be analyzed as if they were real observations of galaxies. These simulations can help answer two outstanding key questions in astrophysics: Can observations accurately measure outflows? and Do feedback models reproduce observations?