Matthew O'Callaghan portrait

Matthew O'Callaghan

Postdoctoral Astrophysicist ยท Center for Astrophysics | Harvard & Smithsonian

Google Scholar NASA ADS arXiv GitHub LinkedIn matthew.ocallaghan@cfa.harvard.edu

Misspecification-Robust Simulation-Based Inference

Developing simulation-based inference methods that stay reliable when simulators do not perfectly describe the data, using learnt error models to deliver calibrated, amortised posteriors at the scale of large surveys such as NASA's Nancy Grace Roman Space Telescope, where I am building foundational stellar and dust products.

Dust Mapping and Stellar Parameter Inference

Data-driven extinction and reddening inference from Gaia distances and photometric surveys, with probabilistic modeling of intrinsic colors to recover robust stellar and dust posteriors.

Supernovae Cosmology

Using BayeSN in lensing-aware inference pipelines to constrain cosmological parameters, including H0, from Type Ia supernova observations.

Timeline

  • Sep 2026

    My paper "Robust Amortised Simulation-Based Inference via Learnt Error Models" was accepted at NeurIPS 2026!

  • Sep 2026

    I have accepted an offer to work at the Centre for Astrophysics | Harvard & Smithsonian with Catherine Zucker, where I will be looking at stellar parameter and dust inference for NASA's Nancy Grace Roman Space Telescope.

  • Feb 2026

    I have started a postdoctoral position at the University of Cambridge working with Kaisey Mandel on inference for supernovae cosmology.

  • Nov 2025

    I successfully defended my thesis at the University of Cambridge!

  • Nov 2025

    My paper "Data Driven Dust Inference at High Galactic Latitudes using Probabilistic Machine Learning" was accepted for publication at MNRAS.

  • Dec 2024

    My paper "Quantifying Extinction at High Galactic Latitudes" has been accepted for publication in MNRAS.

  • Mar 2024

    I have started a six-month research assistant position at the National Observatory in Athens, working on inference for atmospheric dust particles.

  • Mar 2022

    I have been awarded the Lloyd Exhibition Prize and Gold Medal from Trinity College Dublin.

  • Oct 2021

    I have started my PhD in Astronomy and Data Intensive Sciences as a Gianna Angelopoulos Science and Innovation Scholar at the University of Cambridge, where I will be working with Gerry Gilmore and Kaisey Mandel.

  • Jul 2021

    I have graduated from the Part III MASt in Mathematics at the University of Cambridge.

  • Nov 2020

    Graduated with B.A. in Mathematics from Trinity College Dublin.