Christian Kragh Jespersen

Christian Kragh Jespersen

PhD Candidate in Astrophysical Sciences

Princeton University

Department of Astrophysical Sciences

Biography

I am a 5th and final-year PhD Candidate working at the Department of Astrophysical Sciences at Princeton University. I am advised by Peter Melchior and David N. Spergel. I work on applying new statistical methods to astrophysics, integrating inductive biases, geometric and physical constraints into well-calibrated Bayesian and Machine Learning models. My main interests are extragalactic, but I am interested in almost all areas of astronomy (e.g., the molecular structure of interstellar dust). My thesis will focus on constructing a link between low-dimensional representations of dark-matter only cosmological simulations and observed galaxy spectra. This will be achieved with data from the Prime Focus Spectrograph (PFS), which I optimize by understanding and using the emission of the atmosphere itself (airglow) to improve the instrument calibration.

As you may be able to tell, I love integrating my science vertically, from instruments to analyses. In short, I like modelling and measuring (astronomy-related) things, so if you have problems meeting any of these criteria, I will be excited to work with you!

Outside of PFS, I am also a member of the Learning the Universe (LtU) collaboration and the Legacy Survey of Space and Time Dark Energy Science Collaboration. I am affiliated with multiple research groups including the Astro Data Lab, led by Peter Melchior, and the Cosmology x Data-science group at the Flatiron Institute led by Shirley Ho.

I love showing our wonderful universe to the public, and I frequently lead the public observing nights at Peyton Hall, and give outreach talks at Astronomy On Tap Trenton.
Outside of academia, I like all things to do with mountains, oceans, and gardening (I organize the local community garden).
Originally from Denmark, I obtained my Bachelor’s degree from the Niels Bohr Institute at the University of Copenhagen in 2021, with a thesis on Neutrino Detection in IceCube.

Last updated Oct 11th, 2025.

Interests
  • (Geometric) Machine Learning
  • Galaxy Evolution
  • Spectroscopy
  • Terrestrial airglow
  • Cosmology
  • Transients
Education
  • PhD in Astrophysicical Sciences, 2026

    Princeton University

  • MA in Astrophysicical Sciences, 2023

    Princeton University

  • BSc in Physics, 2021

    University of Copenhagen

Research

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Publications

I would never keep everything here up to date, so for an up-to-date list, instead look at the amazing NASA/ADS service. Sometimes, web services track my name as “Kragh Jespersen, Christian”, sometimes as “Jespersen, Christian Kragh” (the correct form), and sometimes as “Jespersen, Christian K.”, so I recommend using the above link to get correct results.

Contact

Please reach out to me if you have any questions regarding science or general academic life, as well as if something on this site is not working. Here are some ways of doing so. Thank you!