Dark energy properties from the combination of large-scale structure and weak gravitational lensing in the Dark energy survey /

• Autores: Carles Sànchez
• Directores de la Tesis: Ramon Miquel Pascual (dir. tes.)
• Lectura: En la Universitat Autònoma de Barcelona ( España ) en 2017
• Idioma: español
• Tribunal Calificador de la Tesis: Enrique Gaztañaga (presid.), Nico Hamaus (secret.), Hendrik Hildebrandt (voc.)
• Programa de doctorado: Programa de Doctorado en Física por la Universidad Autónoma de Barcelona
• Materias:
  • Astronomía y astrofísica
• Enlaces
  • Tesis en acceso abierto en:  DDD  TDX 
• Resumen

  • My PhD thesis was focused on extracting cosmological information from photometric galaxy surveys, in particular the Dark Energy Survey, while minimizing the impact of dominant systematic errors. The thesis includes work on both the first and last stages of survey data analysis, from photometric redshifts (photo-z’s) and shear systematics testing to cosmological parameter estimation using large-scale structure (LSS) and weak gravitational lensing (WL). I performed the first assessment of the photo-z capabilities of the DES Camera by using an extensive set of photo-z algorithms, and data from the DES Science Verification (SV) period matched to spectroscopic data from surveys like VVDS, zCOSMOS and ACES. That part provides a thorough comparison between training and template-based photo-z methods using real data. On WL, I characterized the galaxy-galaxy lensing signal for a variety of galaxy samples, including exhaustive systematics testing and the study of the galaxy bias, which describes the way galaxies populate dark matter halos. Beyond the usage of galaxies as lenses, I also studied the lensing signal produced by cosmic voids, for the first time in a photometric survey, using a new void finder I designed specifically for such data sets, and which I applied as well to the study of the Integrated Sachs-Wolfe effect. Finally, as a conclusion and major piece of work in the thesis, I measured the angular galaxy clustering and galaxy-galaxy lensing of luminous red galaxies in the DES-SV sample and combined them to conduct the first cosmological analysis from the combination of LSS and WL probes in DES. The results are not competitive with those from Planck (DES-SV comprises only about 3% of the final DES data sample) but show consistency with the DES cosmic shear analysis and establish a benchmark in the modelling and treatment of systematic errors for future combinations of probes in DES and the next generation of galaxy surveys like LSST, WFIRST and Euclid.