Relativistic Jets Shine through Shocks or Magnetic Reconnection

By L. Sironi, M. Petropoulou, D. Giannios. 2015

255 citations recorded by the source corpus.

Observations of gamma-ray-bursts and jets from active galactic nuclei reveal that the jet flow is characterized by a high radiative e ffi ciency and that the dissipative mechanism must be a powerful accelerator of non-thermal particles. Shocks and magnetic reconnection have long been considered as possible candidates for powering the jet emission. Recent progress via fully-kinetic particle-in-cell simulations allows us to revisit this issue on firm physical grounds. We show that shock models are unlikely to account for the jet emission. In fact, when shocks are effi cient at dissipating energy, they typically do not accelera te particles far beyond the thermal energy, and vice versa. In contrast, we show that magnetic reconnection can deposit more than 50% of the dissipated energy into non-thermal leptons as long as the energy density of the magnetic field in the bulk flow is larger tha n the rest mass energy density. The emitting region, i.e., the reconnection downstream, is characterized by a rough energy equipartition between magnetic fields and radiating partic les, which naturally accounts for a commonly observed property of blazar jets.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/d23c894b44361fdb17e39363daf979b76227c44c

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Citations in the corpus

Non-thermal particle acceleration in collisionless relativistic electron-proton reconnection (2016, background): “Such ‘minijets’ could represent outflow regions from relativistic reconnection sites (Giannios et al. 2009; Nalewajko et al. 2011), with local values of σi several times larger than the mean.”
First Sagittarius A* Event Horizon Telescope Results. V. Testing Astrophysical Models of the Galactic Center Black Hole (2022, methodology): “Since we are modeling quiescent emission, we assume a steep power-law index of p= 4 with a constant nonthermal acceleration efficiency ò= ne, power-law/ne, thermal= 0.1, typical of PIC simulations (e.g., Sironi et al. 2015; Crumley et al. 2019).”
Plasmoids in relativistic reconnection, from birth to adulthood: first they grow, then they go (2016, methodology): “…2007; Lyubarsky & Liverts 2008; Cerutti et al. 2012; Sironi & Spitkovsky 2014; Guo et al. 2014, 2015; Liu et al. 2015; Nalewajko et al. 2015; Sironi et al. 2015; Werner et al. 2016; Kagan et al. 2016) and three dimensions (3D; e.g., Zenitani & Hoshino 2005, 2008; Yin et al. 2008; Liu et al.…”