Spectral and timing properties of black-hole low-mass X-ray binaries

Low-mass X-ray binaries (LMXBs) are binary systems that consist of a compact object (i.e., a black hole or a neutron star) and a low-mass star (less than 1 solar mass), known as companion star, orbiting around a common center of mass. If the two components are close enough, the compact object accretes matter from the companion star forming an accretion disc that produces strong emission in X-rays. A hot electron plasma, called the corona, surrounds the compact object and the accretion disc. Energetic electrons in the corona interact with the photons coming from the accretion disc via inverse Compton scattering to produce the hard X-rays observed in these systems. The emission from the accretion disc and the corona varies with time, producing different spectral states.In this thesis, I study the evolution of the spectral and timing properties of LMXBs with a black hole as a compact object, the so-called black-hole low-mass X-ray binaries (BH LMXBs). The study of these properties allowed me to infer the nature of the compact object of these systems, as well as shed light on some phenomena that are not very well studied, such as Failed-Transition outbursts and reflares