I am interested in understanding what the structure and dynamics of galaxies can tell us about the properties of dark matter. To do this, I develop N-body simulations and analysis methods to identify observables that can inform us about the distribution and nature of dark matter. All my publications can be found through ADS. Below I summarize the main research projects I have led or worked on with collaborators.

The ongoing merger between the Milky Way and the LMC

With a mass of about 10–20% of that of the Milky Way, the LMC has just passed its first pericentric approach around the Galaxy. Its gravitational field is inducing perturbations in the Milky Way, opening an exciting opportunity to study how the galaxy’s dark matter behaves during a merger. As part of this response, the LMC induces a dark-matter wake in the Milky Way’s halo that trails the LMC. Such a wake is visible as an overdensity of Milky Way stars following the LMC. One of the first predictions of the properties of such a wake was presented in Hunting for the Dark Matter Wake induced by the Large Magellanic Cloud.

An illustration below shows the response of the Milky Way’s dark matter to the LMC as measured by Gaia and WISE. The dark matter halo is shown in purple, and the wake trailing the LMC is visible.

All-sky view of the Milky Way-LMC interaction and associated wake

Image credit: NASA/ESA/JPL-Caltech/Conroy et al., 2021

Observational characterization of the Milky Way’s response to the LMC’s passage

This work motivated the search for the stellar wake in Gaia data and other surveys. I have contributed to several such measurements in Conroy et al. 2021 and Cavieres et al. 2025.

The gravitational torques from the LMC on the Milky Way also induce an apparent motion of halo stars with respect to the disk, known as reflex motion. This motion has been detected in Gaia data, and it has also been measured by surveys such as SDSS-V (Chandra et al. 2025).

The perturbations from the LMC on the Milky Way are also present in the circumgalactic medium, as studied by Chris Carr (Carr et al. 2025), and in the disk of the Milky Way, as discussed by collaborator Chervin Laporte. See also Laporte et al. 2018a, Laporte et al. 2018b, and Stelea et al. 2024.

These observational and theoretical studies have therefore put forward a new picture in which the Milky Way is in a state of disequilibrium.

Constraining the nature of dark matter with the MW-LMC interaction

Excitingly, the disequilibrium state of the Milky Way offers a unique opportunity to study how dark matter behaves out of equilibrium. This includes the properties of the dark matter wake (Foote et al., 2023) and the distribution and kinematics of solar-neighborhood particles as studied by Gurtina Besla in Besla et al., 2019 and in Smith-Orlik et al., 2023, which could potentially be detected through direct-detection methods.

The LMC also brings its own population of subhalos with different kinematics from those of the Milky Way. With Arpit Arora, we characterized the kinematical properties of LMC subhalos and predicted potential signatures in the Milky Way stellar stream population (Arora et al., 2024).

Orbits of stellar tracers in a time-dependent Milky Way potential

The response of the Milky Way to the LMC has consequences for interpreting the dynamics of objects orbiting in the stellar halo of the Milky Way. Below I list a few examples of such consequences:

Orbital poles clustering from LMC

The apparent orbital poles clustering of halo particles induced by the LMC. Image credit: Garavito-Camargo et. al., 2021b

Methods to characterize galaxies in disequilibrium

I have developed and implemented new methods to characterize and interpret the degree of dynamical disequilibrium in galaxies. To do this, I use Basis Function Expansions (BFE). The animation below illustrates such decomposition in one of the dark matter halos of the MW-est suite of simulations. The response of the halo (left panel) to an external perturber is characterized and decomposed as a function of time using BFE. The evolution of harmonic modes of the expansion is shown in the right-hand panels.

BFE decomposition of Halo340

Image credit: Darragh-Ford et al., 2026

Such methods have allowed us to characterize the dark matter halo response to LMC-like satellites in the velocity fields of idealized simulations as shown by Emily Cunningham Cunningham et al., 2020; and in the density field as shown in Garavito-Camargo et al., 2021 and in cosmological simulations (Arora et al., 2025; Darragh-Ford et al., 2026).

Beyond the Milky Way–LMC interaction