Elizabeth Tasker

Postdoctoral Fellow in Theoretical Astrophysics @ UF

My research has focused on modelling stars & galaxies using the 3-dimensional hydrodynamics code, Enzo. Enzo is an adaptive mesh refinement (AMR) code with routines for star formation and feedback from Type II supernovae. More details about Enzo can be found in a paper by Brian O'Shea et al. (2004).

I am extremely interested in the role of star formation and feedback processes in galactic evolution. Global galaxy models (that is, simulations of a single, but entire, galaxy disc) have reached the stage where it is possible to resolve structures down to the giant molecular cloud (GMC) level of a few 10s parsecs. This enables us to follow the majority of the star forming gas through the whole galaxy and obtain a handle on how star formation affects galaxy properties and evolution. Grid codes (such as Enzo) nautrally create a multiphase interstellar medium, where the wide range of temperatures and densities can be maintained.

A movie of the gravitational fragmentation of a galaxy disk into GMC-sized gas clouds is shown below (click to start). The image is 20 kpc across and the smallest cell size used is 15.6 pc. Lower density gas is in the central region and outskirts of the disk, while the region between r = 2 - 10 kpc is unstable by having a Toomre Q < 1.

A significant amount of numerical developement of Enzo has been required to work on the above projects which led me to explore the differences in astrophysical codes quantitatively. My main paper on this topic has recently been accepted to MNRAS and has an accompanying website at: http://www.astro.ufl.edu/codecomparison.