I study the chemical structure of the Milky Way using SDSS3 APOGEE observations. I have developed routines to estimate distances to all the stars in the APOGEE survey using Bayesian analysis, comparing the derived spectroscopic parameters to model isochrones along with spatial density priors to determine the most likely distance to each star. From the first year of APOGEE observations, we generated mean metallicity maps of the Milky Way and measured radial and vertical gradients throughout the disk of the Galaxy.

The latest public data release for the SDSS (DR12) contains three years of APOGEE observations. We use nearly 71,000 giants to measure the metallicity distribution function and categorize the [a/M] vs. [M/H] plane. We found that the peak and shape of the MDF is strongly dependant upon location within the Galaxy, and that radial migration was needed to explain our results. We also found that the inner disk could potentially be explained by a single track in the [alpha/M] vs. [M/H] plane, starting with metal-poor stars at high-alpha abundances and ending with metal-rich ([M/H]~0.5) solar-alpha abundance stars.

For more information on my past research, visit my department research page.