The MUSIC of Galaxy Clusters: A database of synthetic clusters from cosmological hydrodynamical simulations
Galaxy clusters are the most massive gravitationally collapsed objects in the Universe. They are also the most rare objects and, therefore, large computational volumes have to be simulated if one wants to obtain a statistical significant sample of such objects that can be used to calibrate the global scaling relations, or to understand the possible mass biases due to inaccuracies of the classical assumption of hydrostatic equilibrium of the Intra Cluster medium. But, due to computational limitations, it is still not possible to simulate Gigaparsec size volumes with enough numerical resolution to accurately describe the internal structures of massive clusters. Therefore, an alternative is to identify the most massive clusters formed in pure N-body simulations of Gigaparsec size boxes, and then re-simulate regions around these objects with high resolution, including baryons (gas and stars) and their complex interactions (hydrodynamics and radiative, short scale processes). Using this technique we have developed the Marenostrum MUltidark SImulations of galaxy Clusters (MUSIC) database of numerical massive galaxy clusters, composed by several thousands of these objects in different cosmologies and with different physic modelling of the baryonic effects. This database has proved to be extremely useful for a number of cosmological and astrophysical studies on clusters. From the raw numerical data we have computed synthetic observations in different wavelengths ranging from radio, through the Sunyaev-Zeldovich effect, optical from star light formed in simulations, to the X-rays of the intra cluster gas. These synthetic observations can then be used for comparison and forecasting with the present and upcoming observational experiments on galaxy clusters.