Current Research Areas:

  • Galaxy Evolution

Hierarchical growth of galaxies and stellar halos; relation between galaxies, quasars, and dark matter halos; reionization of the universe by galaxies; galaxy quenching; evolution of satellite galaxies.  Formation and evolution of the Milky Way galaxy.

  • Large Spectroscopic Surveys

Design and analysis of large spectroscopic surveys of stars including H3, SDSS-V, and Gaia.

  • Stellar Populations

Building stellar population synthesis models for the interpretation of spectral energy distributions; development of novel semi-resolved stellar population techniques; Bayesian inference of stellar population properties; measuring detailed abundance patterns and the stellar initial mass function from absorption line spectroscopy; modeling nebular emission from galaxies; circumstellar and diffuse dust in galaxies; spectrophotometric calibration.

  • Stellar Evolution

Development of a new, comprehensive grid of stellar evolution models covering all phases of stellar evolution for all stellar masses; constraining uncertain ingredients in stellar models with resolved and unresolved stellar populations.

  • Stellar Spectroscopy

Automated calibration of atomic and molecular line lists based on high quality spectral standards; analysis of low resolution stellar spectra to measure detailed elemental abundance patterns; new grids of stellar atmospheres and spectra for a wide range of chemical compositions.

  • Chemical Evolution

Modeling the evolution of the detailed abundance patterns of galaxies to constrain formation scenarios; exploring the feasibility of `chemical tagging' techniques in the Galaxy.