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Kavli Institute for Cosmology, Cambridge

 

Biography

I am a Physics PhD student at the Kavli Institute for Cosmology and the Cavendish Laboratory at the University of Cambridge, working under the supervision of Dr Will Handley. Prior to joining Cambridge, I completed my undergraduate and master's degrees at Imperial College London. My research lies at the intersection of cosmology, advanced Bayesian inference, and machine learning, with a specific focus on rigorous model comparison and tension quantification.

I am the lead developer of unimpeded, a public pip-installable Python library and data repository designed to democratise access to computationally expensive nested sampling chains. Through this work, I have generated a comprehensive database across eight cosmological models and 69 datasets, transforming analyses that previously required months of supercomputing time into seconds. Most recently, I applied this framework to the DESI DR2 data release to critically examine claims of evolving dark energy. I am also a contributing author of anesthetic, a Python package for processing nested sampling chains.

Currently, I am extending this infrastructure to build the next generation of cosmological emulators. By leveraging machine learning techniques such as normalising flows and density estimators, I aim to enable instant, nuisance-free likelihood evaluations for future surveys.

Publications

Other publications: 

Publications

  • unimpeded: A Public Grid of Nested Sampling Chains for Cosmological Model Comparison and Tension Analysis
    D. D. Y. Ong and W. Handley
    arXiv:2511.04661
  • A Bayesian Perspective on Evidence for Evolving Dark Energy
    D. D. Y. Ong, D. Yallup and W. Handley
    arXiv:2511.05470
  • unimpeded: A Public Nested Sampling Database for Bayesian Cosmology
    D. D. Y. Ong and W. Handley
    arXiv:2511.10631
  • Signatures of star formation inside galactic outflows
    D. D. Y. Ong et al.
    arXiv:2512.10924