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My research

Changing-look AGN

AGN are typically classified based on their spectra. Type 1 AGN have broad lines in their spectra, while Type 2 AGN do not. Most AGN unification theories attribute these types to the orientation of the AGN system relative to the viewer.

Changing-look AGN are AGN which gain or lose broad-line emission over timescales of months or years. We still don't know what causes this behavior, but popular theories include changes in the fuel available to the AGN, instabilities in the accretion disk, or transient events like the tidal disruption of stars.

Post-starburst galaxies

Galaxies in the local Universe can be broadly divided into star-forming spiral galaxies and quiescent/quenched (non-star-forming) elliptical galaxies. Galaxies must evolve from star-forming to quiescent by 'quenching,' or shutting down, their star formation. Most quiescent galaxies in the local Universe quenched slowly over billions of years, while quiescent galaxies in the early Universe (which had less time to shut down star formation) did so rapidly. To understand these early-Universe rapid quenching mechanisms, we can study so-called 'post-starburst galaxies,' or galaxies which experienced a burst of star formation followed by rapid quenching, in the local Universe.

My Papers

Identifying Transitions in Changing-look Active Galactic Nuclei in Light-curve Data with the Zwicky Transient Facility (ApJ, 2026)

Changing-look AGN are AGN which gain or lose broad emission lines in their spectra on timescales less than a decade. The exact timescale of this transition is extremely constraining for physical models of AGN accretion state changes, but accurately measuring this timescale requires high-cadence spectroscopic monitoring of large numbers of AGN. In this work, I propose a method to identify a photometric counterpart to the spectroscopic CL-AGN transition. Using light curve data from the Zwicky Transient Facility, I identify significant photometric changes in 5 previously-known CL-AGN. For one object, the photometric change is associated with a new CL-AGN transition, meaning this object is a "repeating" CL-AGN. I use the ZTF data to measure CL-AGN transition timescales and find most occur on timescales of years, not decades. I then explore the possible mechanisms to create such rapid transitions.

Modeling Star Formation Histories of Changing-look AGN Host Galaxies with Prospector (ApJ, 2025)

Changing-look active galactic nuclei, or CL-AGN, are AGN which appear to transition between Seyfert Type 1 and 2 over periods of months to years. Several mechanisms to trigger these transitions have been proposed, but we have yet to conclusively determine their cause. Recent studies suggest CL-AGN are hosted primarily in galaxies which are shutting down star formation, which may indicate a link between galaxy quenching and changing look events. In this paper, I model the star formation histories for 39 CL-AGN host galaxies to test whether CL-AGN live in unique host galaxies. I find that CL-AGN hosts have similar star formation properties to the host galaxies of other AGN, implying CL-AGN state transitions may instead result from nuclear-scale or accretion disk effects.

Merger Signatures are Common, but not Universal, in Massive, Recently Quenched Galaxies at z~0.7 (ApJ, 2023)

Post-starburst galaxies are galaxies that have recently and rapidly stopped forming stars. Galaxy mergers are commonly invoked as a way to induce a rapid starburst, change the shape of a galaxy from spiral to elliptical, and deplete or remove gas in the galaxy, forming a post-starburst. In this work, I visually classify tidal features and asymmetries in post-starburst galaxies as tracers of recent mergers. I find that post-starbursts are about 3.6x more likely to be disturbed than quiescent galaxies and about 2.1x more likely to be disturbed than star-forming galaxies, with the highest merger rates occurring in the brightest and most recently quenched post-starbursts. This work suggests a link between galaxy mergers and the post-starburst phase at intermediate redshift.