My Research

My research interests are in the field of computational astrophysics where I use simulation and theoretical models -- along with my extensive software development skills -- to understand the first galaxies and the transition from metal-free Population III (Pop III) to Population II (Pop II) star formation. Since no one has yet observed a metal-free star, one way to deduce their characteristics is by using theory and simulation to understand the unusual elemental abundances seen in some of the oldest stellar systems studied by observers. These ``stellar fossils'' are thought to have captured the chemical imprint of Pop III supernova (SN) and neutron star mergers (NSM) providing us with clues we can use to understand this first generation of stars.

PDFs for chemical abundances in our simulated stars 

Our probability density functions (PDFs) correlate well with the observations of CEMP stars from Keller et al. (2014) (red stars).

Supernova induced turbulent velocity and fluid-flow (vectors).

Our simulation tracks the pristine fraction of gas at subgrid scales to better model the formation of Pop III stars in the early universe.

Histogram of stellar mass in metallicity bins

We demonstrate that a large number of stars can still form in regions of otherwise polluted gas due to incomplete mixing.

Left: Scatter diagram of the corrected A(C) vs. [Fe/H] from Yoon et al. [2016]. The blue and red open circles represent the 147 CEMP-s/rs stars and 127 CEMP-no stars, respectively. The black diagonal line identifies a carbon-to-metal ratio: [C/Fe] = 0.7. Right: Joint PDF depicting the mass-weighted probabilities, per Mpc3, for A(C) vs. [Fe/H] for all the stars in my simulation. Red stars are a super-set of CEMP-no stars plotted at left. The PDF correlates well with bimodal pattern of CEMP-no (red) stars analyzed by Yoon et al. [2016].

-- A(C) = log (NC/NH) + 12, is the Carbon abundance where A(C)⊙ = 8.43