期刊
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
卷 507, 期 4, 页码 5281-5302出版社
OXFORD UNIV PRESS
DOI: 10.1093/mnras/stab2466
关键词
acceleration of particles; black hole physics; MHD; radiation mechanisms: non-thermal; methods: numerical; galaxies: individual: (Milky Way: Sgr A*)
资金
- National Science Foundation (NSF) [PHY-1125915, AST-1815304, AST-1911080]
- Department of Energy (DOE) office of Science User Facility [DE-AC05-00OR22725]
- Netherlands Organisation for Scientific Research (NWO) VICI grant [639.043.513]
- Black Hole Initiative Fellowship at Harvard University - Gordon and Betty Moore Foundation
- John Templeton Foundation
- Black Hole PIRE program (NSF) [OISE-1743747]
- UKRI Stephen Hawking Fellowship
- Leverhulme Trust Early Career Fellowship
- NWO Spinoza Prize
- Northwestern University
- Royal Society University Research Fellowship
- Natural Sciences and Engineering Research Council of Canada (NSERC)
- Canada Research Chairs program
- Canadian Institute for Advanced Research (CIFAR)
- INCITE program award [PH129]
This study investigates the flare flux distributions of Sgr A* using GPU-accelerated codes, considering the effect of particle acceleration for the first time. The results suggest that non-thermal populations of electrons arising from turbulence-driven reconnection in weakly magnetized accretion flows lead to moderate NIR and X-ray flares, while fulfilling multiwavelength flux constraints.
Sgr A* exhibits regular variability in its multiwavelength emission, including daily X-ray flares and roughly continuous near-infrared (NIR) flickering. The origin of this variability is still ambiguous since both inverse Compton and synchrotron emission are possible radiative mechanisms. The underlying particle distributions are also not well constrained, particularly the non-thermal contribution. In this work, we employ the GPU-accelerated general relativistic magnetohydrodynamics code H-AMR to perform a study of flare flux distributions, including the effect of particle acceleration for the first time in high-resolution 3D simulations of Sgr A*. For the particle acceleration, we use the general relativistic ray-tracing code bhoss to perform the radiative transfer, assuming a hybrid thermal+non-thermal electron energy distribution. We extract similar to 60 h light curves in the sub-millimetre, NIR and X-ray wavebands, and compare the power spectra and the cumulative flux distributions of the light curves to statistical descriptions for Sgr A* flares. Our results indicate that non-thermal populations of electrons arising from turbulence-driven reconnection in weakly magnetized accretion flows lead to moderate NIR and X-ray flares and reasonably describe the X-ray flux distribution while fulfilling multiwavelength flux constraints. These models exhibit high rms percent amplitudes, both in the NIR and the X-rays, with changes in the accretion rate driving the 230 GHz flux variability, in agreement with Sgr A* observations.
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