Bayesian inference for cosmology: Inferring the initial fields of our cosmic neighborhood

When:
31/12/2025 – 01/01/2026 all-day
2025-12-31T01:00:00+01:00
2026-01-01T01:00:00+01:00

Offre en lien avec l’Action/le Réseau : DatAstro/– — –

Laboratoire/Entreprise : CRIStAL / Université de Lille / CNRS / Centrale Li
Durée : 18 mois
Contact : jenny.sorce@univ-lille.fr
Date limite de publication : 2025-12-31

Contexte :
The project is part of the Chaire WILL UNIVERSITWINS (UNIVERSe dIgital TWINS) led by Jenny Sorce (funded by the Université de Lille under the initiative of excellence). The successful candidate will be jointly supervised by Jenny Sorce (CNRS Researcher in cosmology) and Pierre Antoine Thouvenin (Assoc. Prof., Centrale Lille), and hosted in the CRIStAL lab (UMR 9189), Lille, France. The work will be conducted in collaboration with Jean Prost (Assoc. Prof., ENSEEIHT) in the IRIT lab. More than 2000 GPU.hours have already been secured for the project at TGCC on the Irene/Rome partition. They will be used to finetune, validate and deploy the surrogate model to perform Bayesian inference. Access to the medium scale computing center from the University of Lille is also ensured.

Lien vers le site du projet : https://sorcej.github.io/Jenny.G.Sorce/universitwins.html

Lien vers l’offre d’emploi : https://sorcej.github.io/Jenny.G.Sorce/jobads/postdocuniversitwins.pdf

Sujet :
According to the standard cosmological model, about 95% of the Universe is dark. Recent large survey analyses reveal tensions with this model. For instance, the local measurement of the expansion rate and the estimate of the Universe homogeneity differ by more than three standard deviations from those inferred with the first light of the Universe. These discrepancies are at the heart of a heated debate in cosmology to determine whether these tensions require new physical models to be acccounted for, or are mere consequences of systematic biases in the observation processing pipeline. Part of this pipeline relies on cosmological simulations to act as the missing ground truth. However, the simulations only reproduce the statistics of the local cosmic web. A new type of simulations, qualified as constrained, is emerging. Initial velocity and density fields of such simulations stem from observational constraints.

Profil du candidat :
PhD in signal/image processing, computer science or applied mathematics.

Formation et compétences requises :
The project requires a strong background in data science and/or machine learning (statistics, optimization), signal & image processing. Very good Python coding skills are expected. A B2 English level is mandatory. Knowledge in C++ programming, as well as experience or interest in parallel/distributed code development (MPI, OpenMP, CUDA, …) will be appreciated.

Adresse d’emploi :
UMR CRIStAL
Université de Lille – Campus scientifique
Bâtiment ESPRIT
Avenue Henri Poincaré
59655 Villeneuve d’Ascq