Black hole-accreting systems exhibit a rich and complex phenomenology, which provide valuable insights into the physical conditions of the accreting material. In this talk, I will focus on black hole X-ray binaries (BHXRBs) as natural laboratories for probing the behaviour of matter in the vicinity of the central BH. These systems undergo rapid and dramatic changes in their X-ray spectral and timing characteristics as they evolve through distinct accretion states during an outburst. Understanding this complex evolution is key to constraining the geometry, energetics, and variability mechanisms of the accretion flow. By combining spectral and timing diagnostics we can reconstruct the structure of the emitting regions and their dynamic coupling on multiple timescales. I will highlight recent developments in this area and the emerging challenges for our theoretical understanding of accretion physics.

Brief Bio of Dr. Barbara de Marco:

She graduated at the University of Bologna, and obtained her PhD at SISSA in Trieste. As a postdoc she worked in different European research institutes (Centro de Astrobiología del CSIC-INTA in Madrid, Max Planck Institute for Extraterrestrial Astrophysics in Munich, Nicolaus Copernicus Astronomical Centre in Warsaw). Since 2020 she is an assistant professor and Ramón y Cajal fellow at Universitat Politècnica de Catalunya in Barcelona. Her primary research focus is the study of gas accretion and ejection processes in active black hole systems, in order to constrain the physical conditions that characterize the innermost environments around BHs.