Black hole astrophysics grew exponentially with the advent of X-ray astronomy. During
accretion onto a black hole, matter experiences an extreme gravitational and thermodynamical
environment. Understanding accretion onto galactic black holes relied on the studies of the X-ray light
curves and spectra collected by the satellites during the past 5 decades. The light curves are gathered by
satellites where photon counts are stored with respect to their energy and time. They often contain
Quasi-Periodic Oscillations (QPOs) and exhibit time delays or lags between the energy bands. The X-
ray spectrum on the other hand contains energy information and photon counts. In the first part of the
presentation, we will address how the major players of accretion shape the X-ray images, broadband
spectra, and light curves of black holes. In the second half, we will examine major challenges, future
targets, and associated science cases. Finally, we will discuss the future state-of-the-art proposed X-
ray interferometric satellites.
Dr. Arka Chatterjee has been working at UPES as an assistant professor since 2024. Prior to this, he served as a postdoctoral fellow at the University of Manitoba, UNIST, South Korea, and the S. N. Bose National Centre for Basic Sciences. His research focuses on X-ray imaging of accreting black holes, general relativistic effects, and disk–jet connections in accretion disks. He discovered jet-induced soft lags during accretion onto black holes and has expertise in ray tracing, black hole astrophysics, X-ray astronomy, and time-series analysis techniques. He is also a member of the International Astronomical Union (IAU), the Canadian Astronomical Society (CASCA), and the Astronomical Society of India (ASI).