Dottorato - PhD thesis
Area Tematica: RSN 1 - Galassie e Cosmologia
Referenti: Emiliano Sefusatti (
Titolo: Testing Cosmologies beyond the Standard Model with Galaxy Clustering
Decorrenza: 22.05.2024
Descrizione:
The Euclid mission, a large international collaboration, is now one of the most important observational efforts in cosmology. It will provide a catalogue of galaxies covering an unprecedented cosmological volume allowing a precise determination of the statistical properties of the matter distribution at large scales. This in turn is expected to shed light on the Dark Energy and the mysterious accelerated expansion of the Universe, on the nature of Dark Matter, on neutrino masses and several other open problems in fundamental physics and astrophysics. Several tensions affecting the standard LCDM model, including recent hints of a time-varying Dark Energy equation of state from the DESI survey are making these investigations particularly exciting.
The Astronomical Observatory of Trieste and the University of Trieste are deeply involved in the preparation for the mission and the development of the data analysis pipelines.
Possible topics for a PhD thesis, related to such effort, can follow different lines of work, with two main directions.
The first, more speculative, consists in developing Perturbation Theory predictions and implementing them in a likelihood analysis code to explore models beyond the standard ΛCDM. These include cosmologies with massive neutrinos, non-Gaussian initial conditions from inflationary models, non-standard Dark Matter models or simply exploring the Bayesian priors on the model required for an optimal detection of Dark Energy. Given the rapidly evolving nature of the field, the specific topic will be decided at the start of the doctorate, taking into account as well the interests of the candidate. The work will be, for the most part, of numerical nature, but with the possibility of exploring new analytical tools.
A second direction, closer to observations, focuses instead on the exploitation of the spectroscopic galaxy sample and specifically on developing a pipeline for the joint analysis of the galaxy power spectrum and bispectrum, optimising estimators and analytical models for the covariance of such observables. While the analysis of the power spectrum is nowadays near-optimal in terms of measurements, theoretical modelling and error estimation, this is not the case for the galaxy bispectrum, where many tools are still approximated and affected by systematic errors. The work will be of numerical nature, and will focus on bringing these tools to full maturity, in the specific context of the Euclid mission. It will include developing tools to account for finite-volume and wide-angle effects and the mitigation of observational systematic effects, with direct participation in the upcoming Euclid Data Release 1 papers, with the first expected for the end of 2025.
The thesis will be developed under the supervision of Dr. Emiliano Sefusatti, lead of the Higher Order Correlation Functions WP and member of Nonlinear Modelling WP, and in close collaboration with Prof. Pierluigi Monaco, lead of the Observational Systematics WP, both WPs part of the Euclid Galaxy Clustering Science Working Group. The candidate will be part of a local group of students and postdocs at the University, the Observatory and SISSA and will be part of teams encompassing several Euclid groups in Italy and Europe.
See also the LSS@Trieste website: https://sites.google.com/inaf.
Allegato: download pdf
