The morphology-density relation, ram-pressure stripping and ultra-diffuse galaxies in extra high resolution galaxy cluster zoom-in simulations

• Applicant: Professor Dr. Klaus Dolag
• Subject Area: Astrophysics and Astronomy
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 516355818

Galaxy clusters and their impact via star-formation reduction, i.e. quenching, on individual satellite galaxies has been the focus of extensive observational research in recent years. As all satellite galaxies are processed in galaxy clusters, an opportunity arises to study the environmental dependence of galaxy evolution. The primary goal of this proposal is to understand the following question: How and to what extent does ram-pressure stripping in galaxy clusters contribute to the build-up of the morphology-density relation (an observational relation between environmental density and morphological galaxy type)? This is closely related to the second focus of the proposal, namely the evaluation and weighting of environmental quenching mechanisms in galaxy clusters. This, in turn, is connected to a third question: What are possible evolutionary pathways in galaxy clusters for the formation of the recently discovered ultra-diffuse galaxies (UDGs)? To understand these connections, we will perform extremely high resolution zoom-in simulations based on the treatment of physical processes used for the cosmological hydrodynamical simulation set \textit{Magneticum Pathfinder}, which have proven to successfully reproduce various properties of galaxies and galaxy clusters. Our dedicated goal is to resolve both ram-pressure stripping and the formation mechanism(s) of UDGs with an unprecedented level of detail. To this end, we aim at simulating 24 galaxy clusters with halo mass M_halo > 1e15 M_sol, resolved with almost 1e9 particles within the virial radius, giving a dark matter particle mass of m_dm~4e6 M_sol/h and a gas particle mass of $m_gas ~ 7e5 M_sol/h, resulting in a spatial resolution of the star particles of ~240 pc/h. With the proposed extreme high resolution we will be able to spatially resolve all necessary physical processes (especially turbulent mixing) involved in satellite galaxy quenching and UDG formation. In addition, we also plan to push the resolution for at least one cluster to ten times better mass resolution, increasing the spacial resolution to ~100 pc/h. As such, this project offers the unique opportunity to profoundly increase our understanding of how galaxy clusters transform their satellite galaxies.

• DFG Programme: Research Grants