RT info:eu-repo/semantics/doctoralThesis
T1 Cross-correlation between cosmic microwave background anisotropies and future galaxy surveys
A1 Bermejo Climent, José Ramón
A2 Programa de Doctorado en Astrofísica
K1 Cosmología
K1 Cosmogonía
AB The cosmic microwave background (CMB) is a snapshot of the Universeat early times (z ∼ 1100). In the recent years, several experiments haveprovided constraints on the concordance ΛCDM model from a statistical analysis of the CMB anisotropies. On the other hand, many galaxysurveys will measure the 3D distribution of the dark matter componentof the Universe with unprecedented sensitivity and sky coverage. This isa complementary probe to the CMB, since it traces the evolution of theUniverse at low redshift.The addition of the two probes will break degeneracies in the parameters which are left when using either CMB or large scale structure (LSS).Moreover, the contributions to the CMB anisotropies along the line-ofsight -the so-called secondary CMB anisotropies- are correlated with thegrowth of perturbations at low redshift. Therefore, we have an importantinformation in addition to the simple combination of the CMB with largescale structure (LSS) probes from galaxy surveys: the cross-correlation between the CMB and LSS probes, such as galaxy number counts and weaklensing. In this thesis, we study the capability of the CMB-LSS crosscorrelation for constraining cosmological parameters alone or in combination with the CMB and LSS, using mock data and statistical methodologies, in the perspective of upcoming and future cosmological surveys.First, we explore the capabilities of the lensing ratio between the CMBlensing - galaxy clustering and weak lensing - galaxy clustering crosscorrelations, an estimator that under certain approximations is independent on some astrophysical uncertainties such as the galaxy bias and on themultipoles. We forecast a measurement of this ratio with an error around1-2% using Euclid and future CMB lensing experiments. Furthermore,we evaluate the impact on this ratio of the inclusion of general relativity contributions to the galaxy number counts. We find that accounting forthe lensing magnification contribution induces a multipole dependence ofthe ratio that will not be negligible for future surveys, and propose a newestimator in order to take it into account. With the new formalism, weforecast by a Fisher matrix approach the capability of the lensing ratiofor constraining cosmological parameters when it is added to the CMBinformation. We find that in extended cosmological models the lensingratio can improve the errors on the dark energy parameters of state andon the curvature density.We have also investigated the global importance of the CMB - LSScross-correlation in a 2D tomographic approach for a joint analysis CMBand galaxy number counts in the angular space. For this, we compute bya Fisher matrix approach the joint constraints on many extended cosmological models, including the dark energy parametrization for a redshiftdependent equation of state, neutrino physics and primordial Universe parameters. We find that the inclusion of cross-correlation can improve thedark energy figure of merit up to a factor ∼ 2. We forecast a detectionof the neutrino mass with ∼> 3σ significance by combining CMB-S4 withSPHEREx, just by the analysis of quasi-linear scales. We also predict themeasurement of the primordial local non-Gaussianity parameter fNL withan uncertaintiy ∼1-2 by combining the CMB with future radio continuumsurveys such as SKA. Our methodology is then applied to models of features caused by deviations from a power law primordial power spectrum.We find that the cross-correlation is useful for helping to constrain thesemodels, in particular for surveys with large redshift coverage such as theradio continuum ones. As a further step, we extend the analysis to theinclusion of weak lensing as additional probe and present the results forthe combination of the full Euclid likelihood with the CMB.
YR 2021
FD 2021
LK http://riull.ull.es/xmlui/handle/915/28284
UL http://riull.ull.es/xmlui/handle/915/28284
LA en
DS Repositorio institucional de la Universidad de La Laguna
RD 12-jul-2024