CosmoStat Calendar

Title: Bridging Stage III and IV: Advancing Systematics Modelling and Theoretical Predictions for Precision Cosmology with Machine Learning

Abstract:
As upcoming surveys like Euclid and Rubin usher in the era of precision cosmology, accurately modelling both observational systematics and theoretical predictions has become more critical than ever. Recent results from KiDS-Legacy demonstrate that refined treatment of systematics — such as photometric redshift biases — can significantly shift cosmological constraints, bringing them into closer alignment with CMB measurements. This underscores the urgent need for robust and scalable methods to address such effects across the entire inference pipeline. In this talk, I will present a suite of machine-learning-based frameworks designed to strengthen the connection between data and theory in cosmological analyses. I begin with an unsupervised approach using Self-Organising Maps (SOMs) to mitigate spectroscopic incompleteness by augmenting synthetic galaxies, thereby enhancing photometric redshift calibration, fulfilling sub-precent level accuracy for Rubin LSST. I then introduce a generative compression scheme based on Variational Autoencoders (VAEs) for efficient uncertainty marginalisation, alongside a tensorised framework that accelerates angular power spectrum computations using parallel GPU operations, also allows for fully analytic marginalisation. Finally, I will present preliminary work employing symbolic regression models trained on large-scale simulations to enable fast and interpretable predictions of halo statistics. Together, these tools provide more accurate, efficient, and flexible modelling of both observational systematics and theoretical predictions — paving the way for robust science outcomes from Stage IV cosmological surveys.

https://cnrs.zoom.us/j/95128135384?pwd=7H0047jpFK6wzmvb2vF3huitaufxM0.1

slides:
https://docs.google.com/presentation/d/1LRJqN8Eb7-g-tlDmRaEJV7yd77FQ5PO01HK53YaTscU/edit?usp=sharing

zoom link:
https://cnrs.zoom.us/j/97784959178?pwd=Z0NqaVR0RmMyNFNFdDR3NHRwUWREZz09

Salle Kepler

slides:
https://docs.google.com/presentation/d/1LRJqN8Eb7-g-tlDmRaEJV7yd77FQ5PO01HK53YaTscU/edit?usp=sharing

zoom link:
https://cnrs.zoom.us/j/97784959178?pwd=Z0NqaVR0RmMyNFNFdDR3NHRwUWREZz09

Salle Kepler

https://cnrs.zoom.us/j/95128135384?pwd=7H0047jpFK6wzmvb2vF3huitaufxM0.1

slides:
https://docs.google.com/presentation/d/1LRJqN8Eb7-g-tlDmRaEJV7yd77FQ5PO01HK53YaTscU/edit?usp=sharing

zoom link:
https://cnrs.zoom.us/j/97784959178?pwd=Z0NqaVR0RmMyNFNFdDR3NHRwUWREZz09

Salle Kepler

slides:
https://docs.google.com/presentation/d/1LRJqN8Eb7-g-tlDmRaEJV7yd77FQ5PO01HK53YaTscU/edit?usp=sharing

zoom link:
https://cnrs.zoom.us/j/97784959178?pwd=Z0NqaVR0RmMyNFNFdDR3NHRwUWREZz09