Principal Investigator
António C. da Silva

Abstract
Understanding the formation and evolution of cosmological structure is a most outstanding challenge in Astronomy. Within this bilateral collaboration we propose to extend our joint work on the study and characterization of the observable properties of the galaxy clusters population in the context of future and ongoing observations. Our primary objective is to characterize structural and scaling properties of distant clusters to quantify the role of non-gravitational physics in the formation and evolution of galaxy clusters, and to study and test for different models of structure formation and cosmology. Our goal is to maximize the extraction of scientific information from cross-correlations between different observational strategies and datasets. A most important aspect of this collaboration consists in combining our group expertises for the optimization of future Planck Surveyor – XMM-Newton (http://sci.esa.int/planck/, http://sci.esa.int/xmm/) data correlations to investigate fundamental cluster physics and to probe for key cosmological ingredients, such as the role of the dark energy, in the formation of cosmological structure. The Planck Surveyor and XMM-Newton experiments are key European Space Agency (ESA) satellite mission dedicated to probe the microwave and X-ray spectral regions, respectively. These are expected to provide a unique insight into the properties of galaxy clusters and constitute a invaluable source of information to constrain both cosmological models and large scale structure formation mechanisms.

In our analysis we will combine both analytical and numerical simulation tools that have been developed by our groups for the study of the formation history of galaxy clusters. For the analytical approach we will use the formalism that we have developed in [2] to investigate the role of dark energy in the gravitational collapse that leads to cluster formation and for predicting cluster cosmological abundances in different models of dark energy. Regarding simulation tools, we will use state-of –the-art hydrodynamics simulations of galaxy clusters populations to produce realistic clusters observations according to Planck Surveyor, XMM-Newton and interferometric instruments specifications. Part of this work will be carried out using existing large scale structure simulations performed within the CLEF-SSH collaboration [1], which include important non-gravitational baryonic gas physical effects, such as radiative gas cooling and energy feedback (heating), in a concordance cosmology scenario. In this project we will also use hydrodynamics simulations featuring different dark-energy models that have been carried out by our group to assess the impact of dark energy on the cluster formation process and evolution of their scaling properties.

Our project is timely and addresses fundamental aspects for the preparation and interpretation of galaxy cluster observations. It spans over a period that optimally includes the important pre-launch phase of the Planck Surveyor satellite (due to be launched in the beginning of 2008). Ground based experiments probing the microwave spectral region will also enter in operation during this period and will provide detailed cluster observations in sky patches and of individual objects. In the X-rays, an upsurge of cluster observations from the XMM-Newton satellite will also become available.

Portuguese Node: CAUP
Co-PI: António da Silva

French Node: IAS - Institut d' Astrophysique Spatiale
Co-PI: Nabila Aghanim

Start
1 January 2007
End
31 December 2008