Sophia Lilleengen

Sophia Lilleengen

Astrophysics PhD Candidate

University of Surrey


I am an astrophysics PhD candidate at the University of Surrey under the supervision of Denis Erkal and Justin Read. For five months in 2022, I joined the Center for Computational Astrophysics at the Flatiron Institute as a Predoctoral Fellow working with Adrian Price-Whelan and Kathryn Johnston. 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 - present

    University of Surrey, United Kingdom

  • MSc in Physics, 2016 - 2019

    University of Heidelberg, Germany

  • BSc in Physics, 2012 - 2016

    University of Heidelberg, Germany


(2021). Measuring the Mass of the Large Magellanic Cloud with Stellar Streams Observed by S^5. In The Astrophysical Journal.

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(2020). Accreted Globular Clusters in external galaxies: Why adaptive dynamics is not the solution. In Cambridge University Press.

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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 – Present 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