Research

Galaxies are not static entities; they change with time. They accrete gas, which is used to form stars, which fuse heavy elements, which are released when these stars die. These elements are ejected from the galaxy by stellar winds or AGN activity, or reincorporated into accreted gas that goes on to form new generations of stars. A galaxy’s abundance of heavy elements, or gas-phase metallicity, is thus sensitive to nearly every process of galactic evolution an astronomer could be interested in, and is a powerful tool for understanding how galaxies change.

I’m interested in how gas-phase metallicity changes in a galaxy population across cosmic time. As galaxies form new generations of stars, the stellar mass of the galaxies increases, as does the metallicity. The relationship between these quantities, known as the mass-metallicity relation, can tell us about galaxy evolution and stellar feedback.

I also think about how what we measure when it comes to metallicity studies may not always represent the complete truth: what bias is introduced, say, by a given survey’s selection function, or our ability to measure metallicity for only very strongly star-forming galaxies with bright emission lines?

RUBIES

As a member of Red Unknowns: Bright Infrared Extragalactic Survey, I am characterizing the mass-metallicity relation at z~5, in one of the earliest populations of galaxies for which a comprehensive set of metallicities have been measured.

LEGA-C Mass-Metallicity Relation

AI used the LEGA-C spectroscopic survey to detail the high-mass end of the mass-metallicity relation and its evolution between z=0.8 and the current day. This project was led by Brett Andrews and Rachel Bezanson, and assisted by Pitt undergraduate Katie Mack and then-high-school-student Mariah Jones. Our work was published in the Astrophysical Journal.