Monte Carlo simulation and data analysis of sky observation mode with the Cherenkov Telescope Array

The success of the current generation of Imaging Atmospheric Cherenkov Telescopes (IACTs) has affirmed the importance of gamma-ray astronomy for modern astrophysics. This field focuses on the upper end of the electromagnetic spectrum, with energies in the range of ~ 50 GeV to hundreds of TeV. Gamma rays, due to their neutral charge, are not disturbed by deflection from magnetic fields in their journey across the Universe, and can be traced back through their incoming direction. Thus, they can address to identify the acceleration processes of high-energy particles close to their acceleration sites, and also answer to some of the most fundamental physics issues, like the Lorentz invariance or the mystery of Dark Matter. Currently in the construction stage, the Cherenkov Telescope Array (CTA) is the next generation ground-based observatory for gamma-ray astronomy at very-high energies and it will exceed its predecessors in every aspect, e.g. energy range, sensitivity, field of view or angular resolution. The galactic and extragalactic surveys are two of the main proposed legacy projects of CTA, providing an unbiased view of the Universe at energies above tens of GeV. Surveys provide an immense service to the researchers community in the context of an open observatory, since they constitute versatile datasets that enable the detection of unexpected sources and provide testing ground for new theoretical ideas. Considering Cherenkov telescopes' limited field of view (FoV), the time needed for those science projects is large. The limited duty cycle of about 1000 hours per year of imaging Cherenkov facilities is a strong motivation to try to reduce the observation time needed for the surveys. The huge number of telescopes of CTA with respect to existing instruments, will allow taking full advantage of new pointing modes in which telescopes point slightly offset from one another, like the divergent mode. This pointing mode leads to an increase in the field of view of the sub-array of telescopes with competitive performance compared to normal pointing of the same sub-array. This type of observation should also improve CTA capacity to detect transient events, such as Gamma Ray Bursts (GRBs), thanks to the Large Size Telescope (LST) fast repointing capability and low energy threshold, and the ability to cover more complex patterns of the sky, like mapping a Gravitational Wave (GW) probability sky map or GRB large error boxes. A divergent pointing mode was included in the CTA science requirements document but, apart from a few publications, up to now it has never been the center of an in-depth study. This thesis is devoted to the improvement of the analysis in divergent mode and to study the performance of this modality for different array configurations and number of telescopes, in order to investigate if the performance are competitive compared to normal pointing.