PhD position in cosmology, to work on the RedH0T project

Overview

The Institute for Theoretical Particle Physics and Cosmology (TTK) at RWTH Aachen University invites applications for one PhD position in cosmology under the supervision of Julien Lesgourgues (salary scale: 75% of E13 TVL). The appointment is for three years, starting around October 2026.

Description

The student will work on the measurement of cosmological parameters from Baryon Acoustic Oscillations data, as well as its combination with other probes (including primordial element abundances from Big Bang Nucleosynthesis). On the one hand, they will participate to the team effort of the Euclid collaboration to measure BAOs (with a particular focus on the robustness of the measurements and the analysis of all underlying assumptions and systematics). On the other hand, they will revisit the analysis of previous data sets on BAO (and potentially BBN), with a similar focus. We seek for students having already acquired some good knowledge of astrophysics and cosmology during their Master studies. Previous experience on the modelling and handling of large-scale structure data (acquired through a research project) is a plus.

Collaboration framework

This position is funded by the ERC Synergy Grant 'Red-teaming the Hubble tension' (RedH0T). The overall goal of the project is to understand the Hubble tension, with a methodology based on red-teaming (adversarial collaboration), error auditing and synergy between various probes. While focusing on BAO (and potentially BBN), the student will participate to the activities of the whole network. They will have opportunities to collaborate with several international experts who are part of the project, and visit them for extended periods.

Application

The selected student should hold their Master degree on the first day of employment. We strongly encourage applications from qualified women and underrepresented minorities. Applicants should provide a curriculum vitae, as well as a brief a research statement (up to one page, outlining past research experience, future plans, and fit to the position). Applications should be send to the email address: before December 15, 2025. In the subject field, please include at least the word ‘RedH0T 2025’ and your family name (e.g.: ‘application RedH0T 2025 Lemaitre’). In addition, you should arrange for two to three letters of recommendation to be sent by your referees to the same address. In case you are also interested in the other position that we are advertising, ‘darkes 2025’, you need to send two applications to the same address, but with different subject fields. However, the letters of recommendation only need to be sent once.