GalaxyHalo Group @ UCSD

Our group's research spans the evolution of the faintest galaxies in the nearby universe, the formation of cosmic structure, and the fundamental nature of dark matter. We tackle these problems using advanced cosmological simulations, computational and theoretical techniques, and the latest galaxy survey and gravitational lensing data.

The GalaxyHalo Group at UC San Diego
2025–26. From left: Sandip Roy, Devontae Baxter, Stephen Canino, Ethan Nadler, Roxanne Lai, Sophia Um, Zewei Wu, Ollie Jackson.

Graduate students and postdocs

Sandip Roy
Sandip Roy
Postdoctoral scholar
Astronomy & Astrophysics and Schmidt AI in Sciences Postdoctoral Fellow

Sandip is developing simulations of galaxy and dark matter structure and using machine learning techniques to reveal observable signatures of new dark matter physics.

Ollie Jackson
Ollie Jackson
Astronomy & Astrophysics Ph.D. student
Katzin Prize Fellow · ARCS Foundation Fellow

Ollie is a graduate student using cosmological simulations to model strong gravitational lensing data and probe the nature of dark matter.

Mia Mansfield
Mia Mansfield
Astronomy & Astrophysics Ph.D. student
NSF GRFP Fellow

Mia is studying galaxy evolution in the local universe using simulations and survey data.

Wisha Wanichwecharungruang
Wisha Wanichwecharungruang
Physics Ph.D. student
Cambridge Part III MASt

Wisha is developing semi-analytic models of subhalo and satellite galaxy populations to test fundamental physics.

Zewei Wu
Zewei Wu
Astronomy & Astrophysics Ph.D. student
LSST Data Science Fellow

Zewei is a graduate student using hydrodynamic simulations of dwarf galaxies to advance galaxy formation theory and near-field cosmology.

Undergraduate students

  • Stephen Canino — Stephen is modeling the evolution of cosmic structure using high-resolution zoom-in simulations.
  • Kaushal Jagdish — Kaushal is studying the density profiles of dark matter halos in warm, fuzzy, and interacting dark matter models.
  • Roxanne Lai — Roxanne is analyzing dark matter substructure in self-interacting dark matter cosmologies.

Co-advised graduate students

  • Omar Kotrach — Physics Ph.D. student. Omar is studying sterile neutrino dark matter production mechanisms and astrophysical constraints.
  • Shahed Shayan Arani — Physics Ph.D. student. Shasha is modeling halo evolution in mixed dark sector models with self-interactions.

Alumni

  • Devontae Baxter — Affiliated postdoc (Coil group), NSF AAPF & UC Chancellor's Postdoctoral Fellow (2024–2026); now Princeton, Future Faculty in the Physical Sciences Fellow; our papers
  • Sophia Um — Astronomy & Astrophysics thesis student (2024–2026); now San Diego State University, M.S. program; our papers
  • Bocheng Feng — Undergraduate researcher (2025); now UT Austin, Ph.D. program; our papers

Papers led by group members

  • S. Um, D. C. Baxter, and E. O. Nadler. Linking orbital history to the quenching of isolated dwarf galaxies. OJAp, submitted.
  • B. Feng, E. O. Nadler, S. P. Oh, and S. Ji. The non-universal pseudo-phase-space density profiles of symphony host haloes. 2026, MNRAS, 546, stag215.

Students and postdocs I have mentored at other institutions are listed on the mentoring page.

I am recruiting undergraduate, graduate, and postdoctoral researchers to join my group at UC San Diego. If you're interested, please email me at enadler@ucsd.edu.