Massive neutrinos and the Large Scale Structure of the Universe

摘要

This thesis deals with the phenomenology of large scale structures in cosmolo-udgies with massive neutrinos. Cosmology has the power to constraint the valueudof neutrino masses down to very high accuracy, but to achieve this targetuda careful description of the effect neutrinos could induce on cosmologicaludobservables is needed.udWith the help on numerical N-body simulations that include a massiveudneutrino component we provide results for clustering beyond the linear leveludof both cold dark matter and neutrinos, comparing the measurements withudanalytical predictions derived in higher order perturbative approaches andudwith existing fitting formulae.udWe also discuss the abundance in mass of tracers of the cold dark matterudlike halos, identifying the right variable, the variance of the cold dark matterudfield, that describe the counts measured in the simulations. We highlight theudsystematics effects introduced by a wrong parametrization of the halo massudfunction, that can bias the inferred cosmological parameters. We presentudresults for the spatial distribution of halos, focusing on the relation withudthe underlying cold dark matter distribution. To this end we computed theudpower spectrum of halos in the simulations, finding that the same variableuddescribing the halo mass function provides a consistent picture of spatialudclustering of the halos.udThe analysis is repeated in redshift space and with higher order correlationudfunctions, the bispectrum in our case, leading to the same conclusions andudreinforcing our results.