Radiative signatures of the jet launching region in astronomical objects
University College Cork
Relativistic jets are observed in a wide range of accreting black hole systems, from stellar-mass black holes in X-ray binaries (XRBs), to supermassive black holes in active galactic nuclei (AGN). However, despite decades of observational and theoretical research, the mechanism by which relativistic jets are launched in nature remains one of the most important unanswered questions in high-energy astrophysics. In this thesis, we investigate various aspects of jet launching by calculating the radiative properties of the inner accretion flow and jet launching region in a range of low-luminosity accreting black hole systems. We treat the plasma dynamics using sophisticated general-relativistic magnetohydrodynamic simulations, and calculate the resulting spectral and temporal radiative signatures using a general-relativistic radiative transport code. In chapter 3, we investigate the high-energy signatures of jets from the inner regions of XRBs, a question which remains an issue when interpreting X-ray observations. We calculate the observational effects of black hole spin in chapter 4, since it is widely expected that black hole spin plays a key role in the process of jet launching. An important unsolved problem in high-energy astrophysics is the origin of variability in blazars (AGN with jets pointing towards us). In chapter 5, we investigate the source of this variability in terms of turbulence in the jet launching region. Finally, in chapter 6 we investigate the observational effects of the mass-loading of jets. Understanding the mass-loading process is crucial for comparing models of jet launching with observations, since the properties of the jet plasma determine the radiative signatures.
Black hole physics , Jets , Radiative processes , High-energy astrophysics , Accretion disks , Relativistic processes
O' Riordan, M. 2018. Radiative signatures of the jet launching region in astronomical objects. PhD Thesis, University College Cork.