059 Cosmology with cross-correlation of data: CMB and Euclid observations

Job title:

059 Cosmology with cross-correlation of data: CMB and Euclid observations

Company:

Centre National d’Etudes Spatiales

Job description

25-059 Cosmology with cross-correlation of data: CMB and Euclid observationsPostuler25-059 Cosmology with cross-correlation of data: CMB and Euclid observations

• Doctorat, 36 mois
• Temps plein
• Indifférent
• Maitrise, IEP, IUP, Bac+4
• Astronomy, Astrophysics

PostulerMissionThe standard cosmological model predicts matter in the recent Universe to be distributed in a cosmic web, with galaxy clusters being the most massive objects and the nodes of this web, and filaments connecting the different nodes. The evolution of this cosmic web is mainly driven by two unknown components: dark matter, which acts only through gravitational effect and controls the collapse of the different structures, and dark energy, that controls the accelerated expansion of the recent Universe.The Euclid satellite is a mission from the European space agency launched in July 2023, with the goal of observing billions of galaxies, tracing the matter distribution in the recent Universe and therefore providing very stringent constraints on dark matter, dark energy and the whole cosmological model. Furthermore, Euclid observations will provide a description of the cosmic web with exquisite precision.From observations, we can mainly access “ordinary” matter, such as galaxies and gas around and between them. Analysing observables related to the recent Universe, such as hot gas and galaxy distribution, comes with the extra challenge of understanding different astrophysical processes (often referred to as baryonic physics). The combination and correlation of different observations targeting the galaxy and gas distribution is therefore fundamental to accurately test the cosmological model.Among the observables of the recent Universe, we have the thermal Sunyaev-Zel’dovich effect (tSZ), due to the interaction of photons from Cosmic Microwave Background (CMB) radiation with free electrons in hot gas. It is a unique tool to describe the distribution of hot gas in the recent Universe, which represents the largest component of matter. In recent decade, several experiments provided measurements of this signal, from the full sky map from the Planck satellite, to measurements of the general amplitude of the signal coming from ground-based telescopes, such as the South Pole telescope (SPT) or the Atacama Cosmology Telescope (ACT). Ongoing and upcoming experiments (such as Simons Observatory, SO) will provide even more precise measurements.The thesis project will mainly revolve around the correlation of tSZ observations with Euclid observables of the matter distribution (galaxy samples and shear maps). The aim will be to improve our general understanding of the recent Universe by identifying and constraining the impact of baryonic physics on the observables, and hence provide tight constraints on the cosmological parameters that describe our model. The PhD candidate will develop physical models of the tSZ signal and its cross-correlation with galaxy distribution. They will also develop the tools and estimators for the measurement of this cross-correlation, first on mock data and then on actual observations.The PhD project will be developed within the Euclid collaboration at the Institut d’Astrophysique Spatiale (IAS). The candidate will join the Euclid collaboration, with the possibility of interacting with a large international community that will help develop their scientific skills. IAS members have a large expertise in the analysis of tSZ, galaxy clusters and filaments, CMB and weak lensing observations. Furthermore, the project will be specifically developed within the Euclid “CMB cross correlation” science working group (CMBx SWG), in the frame of the selected Key-Project “Hot gas in the cosmic web via TSZ cross-correlation with GC, WL and clusters”. The leader of the Key Project (Laura Salvati) will act as supervisor of the PhD candidate, one of the leaders of CMBx SWG (Giulio Fabbian) joining the cosmology team at IAS as Directeur de Recherche, and the former leader of CMBx SWG (Nabila Aghanim) will be also directly involved in the development of the Key Project. The PhD candidate will therefore work in the ideal environment to develop this kind of analysis.For more Information about the topics and the co-financial partner (found by the lab !);contact Directeur de thèse –Then, prepare a resume, a recent transcript and a reference letter from your M2 supervisor/ engineering school director and you will be ready to apply online before March 14th, 2025 Midnight Paris time !ProfilWe look for a candidate with a Master in Astronomy and Astrophysics, with interest and/or expertise in Cosmology and in the analysis of CMB or galaxy survey data. The candidate must also have an experience in coding.

Expected salary

Location

Orsay, Essonne

Job date

Wed, 05 Feb 2025 07:41:40 GMT

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