Astrophysical black holes are as complex as they are fascinating. They can be very large, weighing millions to billions of solar masses while being located at the very center of galaxies – where they are known as Supermassive Black Holes (SMBHs). They may also be relatively small, weighing “only” a few solar masses, but these are no less important or interesting than their heavier counterparts.

SMBHs can be seen as powerful engines that convert the energy of accreting plasmas into extremely luminous radiation and produce outflows that affect the entire galaxy evolution. A similar behavior has also been observed in smaller-sized, stellar-mass black hole X-Ray binaries (BHXBs). Therefore, observations suggest that the study of these two classes of systems may give us complementary information about the general physical processes related to the accretion and outflows around black holes. In turn, theoretical studies may give us hints to actually explain many observational features of these systems.

My work aims precisely to bridge the gap between theory and observation. Despite the existence of analytical models to describe many aspects of these systems, they are too complex to be understood without extensive use of numerical simulations. Thus, if we want to understand the underlying physics of black holes and explain what the observations are showing us, we must make heavy use of powerful numerical tools.

The black holes I study lie at the very core of some of the most physically extreme environments found in the Universe, and in order to describe them, we must make full use of General Relativistic Magnetohydrodynamic (GRMHD) simulations. These are provided by a modified version of HARM. Using data input from these simulations, their spectra are generated using a modified version of grmonty.

Public versions of HARM and grmonty are available here.

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