Galaxy Evolution in Supercluster Environments

The formation and evolution of galaxies is one of the great outstanding problems in astrophysics. Besides the fact that galaxy formation involves so many physical processes that it is intrinsically difficult to model, the environment in which the galaxies live also plays a major rôle. This means that one needs to study galaxies in different environments in order to study its influence on the evolutionary sequence. The proposed project aims to measure and understand the physical processes underlying the transformation and evolution of galaxies, their star formation histories and merger rates, and any other dependence on their environment. The observational effort will be driven by two planned (within the timescale of the project) surveys in the optical and infrared wavebands using the OmegaCAM camera on the VLT Survey Telescope. The first of these surveys is VST-16, which employs 16 filters in as many wavebands to be able to sparsely sample the spectrum of each galaxy, which in turn can be used to determine its distance to us. The other survey is VESUVIO, which aims to map the Hercules and Horologium superclusters in great detail in 5 optical wavebands, with extensive follow-up radio and X-ray observations planned. Both surveys will start at the end of 2005. The theoretical effort is focussed on enhancing and extending an existing model for galaxy formation and evolution that works well for the local universe, but has not been tested for environmental effects. This requires the inclusion of a good model for the relevant processes, especially anything related to mergers and close encounters, and a good model for superclusters and their constituent clusters, which provide a large variety of environments. The final aim is to produce a model that compares well to the observational data, which helps to interpret these data. Specifically, we strive to understand, at the end of the project, which physical processes determine the properties of galaxies, what most influences their properties like bolometric luminosity and morphology, and what the consequences are for galaxy formation models and cosmology.

The formation and evolution of galaxies is one of the great outstanding problems in astrophysics. Besides the fact that galaxy formation involves so many physical processes that it is intrinsically difficult to model, the environment in which the galaxies live also plays a major rôle. This means that one needs to study galaxies in different environments in order to study its influence on the evolutionary sequence. The proposed project aims to measure and understand the physical processes underlying the transformation and evolution of galaxies, their star formation histories and merger rates, and any other dependence on their environment. The observational effort will be driven by two planned (within the timescale of the project) surveys in the optical and infrared wavebands using the OmegaCAM camera on the VLT Survey Telescope. The first of these surveys is VST-16, which employs 16 filters in as many wavebands to be able to sparsely sample the spectrum of each galaxy, which in turn can be used to determine its distance to us. The other survey is VESUVIO, which aims to map the Hercules and Horologium superclusters in great detail in 5 optical wavebands, with extensive follow-up radio and X-ray observations planned. Both surveys will start at the end of 2005. The theoretical effort is focussed on enhancing and extending an existing model for galaxy formation and evolution that works well for the local universe, but has not been tested for environmental effects. This requires the inclusion of a good model for the relevant processes, especially anything related to mergers and close encounters, and a good model for superclusters and their constituent clusters, which provide a large variety of environments. The final aim is to produce a model that compares well to the observational data, which helps to interpret these data. Specifically, we strive to understand, at the end of the project, which physical processes determine the properties of galaxies, what most influences their properties like bolometric luminosity and morphology, and what the consequences are for galaxy formation models and cosmology.