Bayesian anomaly detection for Cosmology - 21cm, Supernovae, and beyond

Add to your list(s) Download to your calendar using vCal

• Samuel Leeney (University of Cambridge)
• Tuesday 27 May 2025, 11:15-12:00
• Martin Ryle Seminar Room, Kavli Institute.

If you have a question about this talk, please contact Charles Walker.

We introduce a unified Bayesian anomaly-detection framework for Cosmology, applied to the REACH global 21cm probe and also Type Ia supernovae. This approach embeds data-integrity beliefs directly into the inference process. Rather than excising contaminated or anomalous data points, the method employs a piecewise likelihood constrained by a Bernoulli prior and an Occam penalty, allowing anomalies to be down-weighted automatically while performing numerical sampling for parameter inference. When applied to supernova light curves, the framework yields precise estimates of brightness scaling, stretch, and colour, while also automating supernova sample and band selection. In the context of global 21 cm cosmology, it offers a principled way to mitigate radio-frequency interference (RFI), particularly within the band of interest. We also discuss additional potential applications of this methodology.

This talk is part of the Hills Coffee Talks series.

This talk is included in these lists:

• All Cavendish Laboratory Seminars
• All Talks (aka the CURE list)
• Cambridge Astronomy Talks
• Cavendish Astrophysics Seminars
• Centre for Health Leadership and Enterprise
• Combined External Astrophysics Talks DAMTP
• Cosmology, Astrophysics and General Relativity
• Featured lists
• Hills Coffee Talks
• ME Seminar
• Martin Ryle Seminar Room, Kavli Institute
• Neurons, Fake News, DNA and your iPhone: The Mathematics of Information
• School of Physical Sciences
• Thin Film Magnetic Talks

Note that ex-directory lists are not shown.