Reconstruction of cosmological density and velocity fields by Fast Action Minimization method: a new code for applications to high-redshift spectroscopic surveys

In this thesis work is presented and tested a new version of the Fast Action Minimization method developed for the reconstruction, backward in time, of the trajectories of a given distribution of point-like particles in an expanding universe. The code is written in c++ and it is optimize for applications to high-redshift spectroscopic surveys as Euclid and DESY. The eFAM allowed to increase the number of objects in the data sample up to order 10^4. The reconstruction is performed assuming a LCDM model for the evolution of the universe with Omega_{m0}, Omega_{L0} and H_0 set by the user. The eFAM can reconstruct particles' trajectories and velocities from observed redshift to the CMB epoch. The eFAM is tested on IRAS PSCz Nbody catalogue, mimicking the Local Supercluster neighbourhood, and on DEUS dark matter haloes Nbody catalogue. The test on DEUS catalogue shows the capability of eFAM to successfully recovers the flow field of the matter particle distribution within a region of 50 Mpc/h when accounting for the matter exterior distribution within 100 Mpc/h from the center of the investigate region.