Constraints on neutrino mass fraction using Redshift Space Distortions

Petracca, Fernanda (2014) Constraints on neutrino mass fraction using Redshift Space Distortions, [Dissertation thesis], Alma Mater Studiorum Università di Bologna. Dottorato di ricerca in Astronomia, 26 Ciclo. DOI 10.6092/unibo/amsdottorato/6728.
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Abstract

Redshift Space Distortions (RSD) are an apparent anisotropy in the distribution of galaxies due to their peculiar motion. These features are imprinted in the correlation function of galaxies, which describes how these structures distribute around each other. RSD can be represented by a distortions parameter $\beta$, which is strictly related to the growth of cosmic structures. For this reason, measurements of RSD can be exploited to give constraints on the cosmological parameters, such us for example the neutrino mass. Neutrinos are neutral subatomic particles that come with three flavours, the electron, the muon and the tau neutrino. Their mass differences can be measured in the oscillation experiments. Information on the absolute scale of neutrino mass can come from cosmology, since neutrinos leave a characteristic imprint on the large scale structure of the universe. The aim of this thesis is to provide constraints on the accuracy with which neutrino mass can be estimated when expoiting measurements of RSD. In particular we want to describe how the error on the neutrino mass estimate depends on three fundamental parameters of a galaxy redshift survey: the density of the catalogue, the bias of the sample considered and the volume observed. In doing this we make use of the BASICC Simulation from which we extract a series of dark matter halo catalogues, characterized by different value of bias, density and volume. This mock data are analysed via a Markov Chain Monte Carlo procedure, in order to estimate the neutrino mass fraction, using the software package CosmoMC, which has been conveniently modified. In this way we are able to extract a fitting formula describing our measurements, which can be used to forecast the precision reachable in future surveys like Euclid, using this kind of observations.

Abstract
Tipologia del documento
Tesi di dottorato
Autore
Petracca, Fernanda
Supervisore
Co-supervisore
Dottorato di ricerca
Scuola di dottorato
Scienze matematiche, fisiche ed astronomiche
Ciclo
26
Coordinatore
Settore disciplinare
Settore concorsuale
Parole chiave
redshift space distortions, neutrinos, clustering, cosmological parameters, markov chain monte carlo
URN:NBN
DOI
10.6092/unibo/amsdottorato/6728
Data di discussione
12 Dicembre 2014
URI

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