LOcal Clusters And supercLuster In sZ: Adding Thermal, kInetic and relativistic cOrrectioNs

• Applicant: Professor Dr. Klaus Dolag
• Subject Area: Astrophysics and Astronomy
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 490702358

Galaxy clusters offer unique opportunities to test the cosmological model. This relies on the use of statistical assessments of their properties from comparison of simulations and observations. To overcome the limitation of statistical approaches, one would ideally need an actual reproduction of the Universe. Constrained simulations now permit building high fidelity clones of the local Large Scale Structure (LSS) of the Universe within 600Mpc diameter valid down to cluster scales. LOCALIZATION will produce and use simulated clones of local clusters and superclusters to fully understand the building up of these cosmic laboratories. We will study their physical and dynamical properties via cosmic flows, X-rays and Sunyaev-Zeldovich signals and we will derive the cosmological signatures of the local LSS on the cosmic background at large scales. LOCALIZATION will pave the way from precision cosmology from averaged statistics towards accurate understanding of the cosmological growth of structures.Indeed, the ΛCDM model is a great success, still the advent of precision cosmology revealed yet unexplained discrepancies between theoretical expectations and observations. Among these the difference between the linearly evolved amplitude of the matter power spectrum measured with the CMB and galaxy clusters, i.e. σ8 tension, as well as CMB large-scale anomalous features. By revisiting these two debated cosmological issues, LOCALIZATION seeks, for the first time, a common solution to both of them. To address this challenge, a comprehensive analysis of the local galaxy clusters and LSS and of their impact on the CMB will be performed based on the hydrodynamical numerical clones of the local Universe up to z<0.07. An unbiased comparison between observational data from Planck and numerical local cluster, supercluster and full LSS clones will be performed.Thanks to LOCALIZATION’s cluster clones, we will derive for the first time the exact relation between cluster masses and their observed proxies. We will address the CMB anomalies in Planck data focusing on sources of CMB signal that contribute at the largest angular scales from the local supercluster and clusters. In addition thanks to the state-of-the-art constrained simulations, we will perform the first exhaustive estimate of the contribution from all possible secondary CMB anisotropies at large angular scales.With LOCALIZATION we will thus answer the following questions: Can the σ8 tension be solved or reduced with a scaling relation exactly and faithfully calibrated thanks to local cluster clones from LOCALIZATION simulations? and How much of the low-multipole CMB anomalies can be explained by the local extragalactic environment fully reproduced by the local LSS clone built within LOCALIZATION?

• DFG Programme: Research Grants
• International Connection: France
• Cooperation Partner: Professorin Dr. Nabila Aghanim