Dynamics and Emission Properties of Flux Ropes from Two-Temperature GRMHD Simulations with Multiple Magnetic Loops

Abstract

Flux ropes erupting from the vicinity of the black hole are thought to be a potential model for the flares observed in Sgr\,A${}^{\ast }$. In this study, we examine the radiative properties of flux ropes that emerged from the vicinity of the black hole. We have performed three-dimensional two-temperature General Relativistic Magnetohydrodynamic (GRMHD) simulations of magnetized accretion flows with alternating multiple magnetic loops, and General Relativistic Radiation Transfer (GRRT) calculations. In GRMHD simulations, two different sizes of initial magnetic loops are implemented. In the small loop case, magnetic dissipation leads to a weaker excitement of magneto-rotational instability inside the torus which generates a lower accretion rate compared to the large loop case. However, it makes more generation of flux ropes due to frequent reconnection by magnetic loops with different polarities. By calculating the thermal synchrotron emission, we found that the variability of light curves and emitting region are tightly related. At $230\mathrm{GHz}$ and higher frequency, the emission from the flux ropes is relatively stronger compared with the background, which is responsible for the filamentary structure in the images. At lower frequencies, e.g. $43\mathrm{GHz}$, emission comes from more extended regions, which have a less filamentary structure in the image. Our study shows self-consistent electron temperature models are essential for the calculation of thermal synchrotron radiation and the morphology of the GRRT images. Flux ropes contribute considerable emission at frequencies $\gtrsim 230\mathrm{GHz}$.

14 pages, 17 figures. Accepted by A&A

References in corpus (29)

• First Sagittarius A* Event Horizon Telescope Results. I. The Shadow of the Supermassive Black Hole in the Center of the Milky Way
• First M87 Event Horizon Telescope Results. V. Physical Origin of the Asymmetric Ring
• First Sagittarius A* Event Horizon Telescope Results. V. Testing Astrophysical Models of the Galactic Center Black Hole
• First Sagittarius A* Event Horizon Telescope Results. III: Imaging of the Galactic Center Supermassive Black Hole
• First Sagittarius A* Event Horizon Telescope Results. II. EHT and Multi-wavelength Observations, Data Processing, and Calibration
• First Sagittarius A* Event Horizon Telescope Results. IV. Variability, Morphology, and Black Hole Mass
• Radiatively Inefficient Accretion in Nearby Galaxies
• An Unambiguous Detection of Faraday Rotation in Sagittarius A*
• Black hole flares: ejection of accreted magnetic flux through 3D plasmoid-mediated reconnection
• Electron and proton heating in trans-relativistic magnetic reconnection
• Sgr A* near-infrared flares from reconnection events in a magnetically arrested disc
• Ab Initio Horizon-Scale Simulations of Magnetically Arrested Accretion in Sagittarius A* Fed by Stellar Winds
• Time Dependent Models of Flares from Sagittarius A*
• Orbital motion near Sagittarius A* -- Constraints from polarimetric ALMA observations
• Polarimetry and Astrometry of NIR Flares as Event Horizon Scale, Dynamical Probes for the Mass of Sgr A*
• State-of-the-art energetic and morphological modelling of the launching site of the M87 jet
• Comparison of the ion-to-electron temperature ratio prescription: GRMHD simulations with electron thermodynamics
• The Flux Distribution of Sgr A*
• The Accretion flow in M87 is really MAD
• Magnetic reconnection plasmoid model for Sagittarius A* flares
• Reconnection-driven flares in 3D black hole magnetospheres -- A scenario for hot spots around Sagittarius A*
• Two-Temperature GRMHD Simulations of Black Hole Accretion Flows with Multiple Magnetic Loops
• A "coronal-mass-ejection'' model for flares in Sagittarius A*
• General relativistic effects and the near-infrared and X-ray variability of Sgr A* I
• Formation of episodic jets and associated flares from black hole accretion systems
• MHD accretion-ejection: jets launched by a non-isotropic accretion disk dynamo. II. A dynamo tensor defined by the disk Coriolis number
• Magnetic field structure in the vicinity of a super-massive black hole in low luminosity galaxies: the case of Sgr A*
• Impact of the nonthermal electron radiation effects on the horizon scale image structure of Sagittarius A*
• Helical and nonhelical large-scale dynamos in thin accretion discs

Cited by in corpus (3)

• The impact of resistivity on the variability of black hole accretion flows
• Non-thermal Synchrotron Emission and Polarization Signatures during Black Hole Flux Eruptions
• Radiative Cooling Effects on Plasmoid Formation in Black Hole Accretion Flows with Multiple Magnetic Loops