Numerical models of the formation of structure in the Universe

Principal Investigator: Pierluigi Monaco


  • Structures in the Universe

Abstract: We use various numerical techniques to simulate the formation of structures in the Universe with supercomputers. We address the formation of large-scale structure from horizon scales down to galactic scales; the astrophysics of galaxy formation is addressed treating, in N-body hydrodynamical codes, several relevant processes with effective models, or is addressed with semi-analytic models applied to simulated dark matter halo merger trees. All these techniques are used to address the following questions: how do we produce large sets of simulations, for error estimation in cosmology? what are the main physical processes responsible for the formation of galaxies and galaxy clusters? what are our forecasts for planned and future galaxy surveys?

Description: Our team is involved in the simulation of structures in the Universe using various numerical techniques. This line of research, that fits well in the IFPU research areas, would greatly benefit from being developed within the IFPU environment: the Institute would create a natural point of contact between researchers of the Trieste area and external collaborators working on the numerical modelling of the formation of cosmic structures, and the interaction with people attending IFPU would trigger new future developments. This is a description of our main activities. Large-scale structure: - We use the Gadget3 TreePM code, modeling a neutrino component with a separated set of collisionless particles. - We are developers of the PINOCCHIO approximated method, able to produce good approximations of a collisionless simulation in a small fraction of computing time. This is needed for the Euclid mission, to produce large sets of simulated galaxy catalogs to compute the error on parameter estimation. N-body hydrodynamical simulations: - We use the Gadget3 TreePM+SPH code to simulate the formation of galaxies and galaxy clusters. - We post-process galaxy clusters to predict their X-ray observed properties with Chandra, XMM and future Athena mission, and their lensing properties. - We develope, within Gadget3, sub-resolution models of star formation and stellar feedback, that take into account the multi-phase nature of the gas at unresolved scales; models to treat gas accretion onto supermassive black holes and its feedback on the surrounding gas; models of dust grain formation. - We post-process simulated galaxies with the GRASIL-3D code to predict their Spectral Energy Distributions from the UV to the FIR, Semi-analytic galaxy formation: - We are the developers of the GAEA semi-analytic model of galaxy formation, able to predict the formation and evolution of galaxies along the whole cosmic history. - We work on improving the treatment of the various physical processed implemented in GAEA (e.g star formation, feedback from stars and AGN, chemical enrichment), also using results from dedicated numerical simulations. - We take advantage of this model to interpret data from a number of ongoing observational programmes, as well as to prepare programmes for planned and future missions like e.g. Euclid, SKA, Spica.