Sophia Lilleengen

Sophia Lilleengen

Postdoctoral Researcher

Durham University


I am a postdoctoral researcher at the Institute for Computational Cosmology at Durham University. I completed my astrophysics PhD at the University of Surrey in June 2023. For five months in 2022, I joined the Center for Computational Astrophysics at the Flatiron Institute as a Predoctoral Fellow. My main research interest lies in stellar streams and whether they are sensitive to time-dependent, deforming dark matter halos. The Milky Way is currently deformed by the infalling Large Magellanic Cloud. Which streams are affected and can trace this? What does this tell us about the nature of dark matter?

  • Stellar Streams
  • Milky Way and Large Magellanic Cloud
  • Dark Matter
  • PhD in Astrophysics, 2019 - 2023

    University of Surrey, United Kingdom

  • MSc in Physics, 2016 - 2019

    University of Heidelberg, Germany

  • BSc in Physics, 2012 - 2016

    University of Heidelberg, Germany


(2024). Action and energy clustering of stellar streams in deforming Milky Way dark matter haloes. arXiv.

Cite DOI

(2023). $S^5$: Probing the Milky Way and Magellanic Clouds potentials with the 6D map of the Orphan-Chenab stream. MNRAS.

PDF Cite Dataset DOI

(2023). Streams on FIRE: Populations of Detectable Stellar Streams in the Milky Way and FIRE. The Astrophysical Journal, ApJ.


(2023). How do the dynamics of the Milky Way-Large Magellanic Cloud system affect gamma-ray constraints on particle dark matter?. MNRAS.



Postdoctoral Research Associate
Jun 2023 – Present Durham, United Kingdom
Pre-Doctoral Research Fellow
Jan 2022 – Jun 2022 New York City, NY, USA
Project: Information Content in Stellar Streams in Time-Dependent Potentials
Postgraduate Research Student
Oct 2019 – Jun 2023 Guildford, Surrey, United Kingdom
Project: Modelling the Effect of Deforming Dark Matter Halos on Stellar Streams
Pre-Doctoral Researcher
Mar 2019 – May 2019 Perth, Australia
Project: The Impact of Lumpiness in a Dark Matter Halo on the Diffusion in Orbits
MSc Thesis Student
Nov 2017 – Feb 2019 Garching, Germany
Project: Adaptive Dynamics - can Orbital Actions of Globular Clusters Constrain the Gravitational Potential of Galaxies?
European Space Agency Trainee
May 2017 – Oct 2017 Madrid, Spain
Project: Characterising Galaxy Evolution in Nearby Galaxy Clusters
BSc Thesis Student
Sep 2015 – Mar 2016 Heidelberg, Germany
Project: Hunting for Intermediate-Mass Black Holes in Simulated Globular Clusters using Integrals of Motion