My Research

Strong gravitational lensing occurs when a massive, foreground galaxy – the deflector – bends the fabric of space, causing light from a background galaxy – the source – to be deflected into multiple "images" around the foreground galaxy; as a result, we can see the source galaxy in multiple places at the same time! The ASTRO3D Galaxy Evolution With Lenses (AGEL) Survey is an ongoing effort to observe and catalog strong lenses for applications in galaxy evolution and cosmology. In AGEL DR2 (Barone et al. 2026), we have spectroscopically confirmed 139 strong lenses, of which ~70 have Hubble Space Telescope Wide-Field Camera 3 (WFC3) imaging for precise lens modeling.

Since 2024, I have conducted research for the AGEL survey with PI Kim-Vy Tran, at the Center for Astrophysics | Harvard & Smithsonian. My research has been funded by awards from the Harvard College Research Program (HCRP) and the Summer Program for Undergraduates in Data Science (SPUDS).

Barone et al. (2026)

From Gottemoller et al. (2026). Environment density vs. mass (the mass enclosed by the Einstein radius) for 85 of the 89 AGEL lenses. The low observed correlation hints that many AGEL deflectors may be satellites in group or cluster environments.

Strong lensing deflectors are known to reside in diverse environments; some deflectors are in massive galaxy clusters, whereas others are isolated galaxies. For my first project with the AGEL survey, we investigated the large-scale environments of 89 AGEL DR2 lenses. To measure environment, we used photometric redshifts to identify deflector environment candidates. We then used projected surface galaxy number densities as our measure for deflector environment. To make comparisons between environment and intrinsic lensing properties, we also measured the Einstein radius – roughly half the angular distance between two source images – to estimate the "lensing mass." We found that roughly 3/4 of our deflectors were located in overdense (group or cluster) environments. Comparing our galaxy number densities of AGEL fields to control fields, we find that AGEL deflectors are located in even denser environments than control fields with galaxies matched to the deflecting galaxy's properties.

In Gottemoller et al. (2026), we theorized that many of the AGEL survey deflectors were satellites in overdense (e.g., group and cluster) environments. In overdense environments, external mass from the deflector environment can enhance the lensing effect, increasing the separation between source images by multiple times (see Oguri et al. 2005). In order to improve strong lens modeling and theoretical predictions, we are investigating how lensing parameters such as magnification and image separation are related to host halo properties (e.g., mass, distance from the center). Using theoretical and computational (IllustrisTNG; Nelson et al. 2019) methods, we have found significant enhancement in the Einstein radius by halo mass and distance from the center of the halo. These results will bridge the gap to the "lensing luminosity function," which will constrain what proportion of photons in the universe are strongly lensed.

Gottemoller et al. (in prep). Einstein radius enhancement by distance from the host halo center of mass, with several different host halo mass scales.

Lin et al. (2019)

Lin et al. (in prep).

Active galactic nuclei (AGN), which are caused by a galaxy's central supermassive black hole, are known to quench star formation through feedback. The global and directional processes by which they quench star formation are not observationally known. With the ALMaQUEST survey, I am analyzing how different galactic processes – AGN feedback, morphology, and environment – quench star formation. We use radial profiles of galaxies' H2 gas fractions and star formation efficiencies (SFE) to measure the "relative contributions" of SFE and gas fractions to quenched star formation rates.

We have preliminary results (see left) for the role of AGN feedback, morphology, and environment in gas fraction and SFE quenching. Our analysis is ongoing, and will be published later in 2026 or 2027.