A magnetohydrodynamic model for multi-wavelength flares from Sagittarius~A (I): model and the near-infrared and X-ray flares
arXiv:1611.02904 · doi:10.1093/mnras/stx655
Abstract
Flares from the supermassive black hole in our Galaxy, Sagittarius~A (Sgr A), are routinely observed over the last decade or so. Despite numerous observational and theoretical efforts, the nature of such flares still remains poorly understood, although a few phenomenological scenarios have been proposed. In this work, we develop the Yuan et al. (2009) scenario into a magnetohydrodynamic (MHD) model for Sgr A flares. This model is analogous with the theory of solar flares and coronal mass ejection in solar physics. In the model, magnetic field loops emerge from the accretion flow onto Sgr A and are twisted to form flux ropes because of shear and turbulence. The magnetic energy is also accumulated in this process until a threshold is reached. This then results in a catastrophic evolution of a flux rope with the help of magnetic reconnection in the current sheet. In this catastrophic process, the magnetic energy is partially converted into the energy of non-thermal electrons. We have quantitatively calculated the dynamical evolution of the height, size, and velocity of the flux rope, as well as the magnetic field in the flare regions, and the energy distribution of relativistic electrons in this process. We further calculate the synchrotron radiation from these electrons and compare the obtained light curves with the observed ones. We find that the model can reasonably explain the main observations of near-infrared (NIR) and X-ray flares including their light curves and spectra. It can also potentially explain the frequency-dependent time delay seen in radio flare light curves.
17 pages, 13 figures, accepted by MNRAS
References in corpus (27)
- Numerical Simulation of Hot Accretion Flows (III): Revisiting wind properties using trajectory approach
- Polarimetry of near-infrared flares from Sagittarius A*
- Flaring Activity of Sgr A* at 43 and 22 GHz: Evidence for Expanding Hot Plasma
- A Magnetohydrodynamic Model for the Formation of Episodic Jets
- X-ray hiccups from SgrA* observed by XMM-Newton. The second brightest flare and three moderate flares caught in half a day
- Radio and Millimeter Monitoring of Sgr A*: Spectrum, Variability, and Constraints on the G2 Encounter
- A polarised infrared flare from Sagittarius A* and the signatures of orbiting plasma hotspots
- Simultaneous Chandra, CSO and VLA Observations of Sgr A*: The Nature of Flaring Activity
- Time Dependent Models of Flares from Sagittarius A*
- Tidal effects on small bodies by massive black holes
- Polarized NIR and X-ray Flares from SgrA*
- Particle Acceleration and the Origin of X-ray Flares in GRMHD simulations of Sgr A*
- NuSTAR detection of high-energy X-ray emission and rapid variability from Sagittarius A* flares
- ALMA and VLA measurements of frequency-dependent time lags in Sagittarius A*: evidence for a relativistic outflow
- A 600 minute near-infrared lightcurve of Sagittarius A*
- Mechanism of Outflows in Accretion System: Advective Cooling Cannot Balance Viscous Heating?
- Properties of the First-order Fermi acceleration in fast magnetic reconnection driven by turbulence in collisional MHD flows
- Polarized light from Sgr A* in the near-infrared -band
- Spitzer/IRAC Observations of the Variability of Sgr A* and the Object G2 at 4.5 microns
- Exploring plasma evolution during Sagittarius A* flares
- Variations in emission from episodic plasmoid ejecta around black holes
- A Systematic Chandra study of Sgr A: I. X-ray flare detection
- Coordinated NIR/mm observations of flare emission from Sagittarius A*
- Towards Self-Consistent Modelling of the Sgr A* Accretion Flow: Linking Theory and Observation
- Flares and variability from Sagittarius A*: five nights of simultaneous multi-wavelength observations
- Modulated X-ray Emissivity near the Stress Edge in Sgr A*
- The Swift X-ray monitoring campaign of the center of the Milky Way
Cited by in corpus (24)
- Magnetic Reconnection and Hot Spot Formation in Black Hole Accretion Disks
- Electron and Proton Acceleration in Trans-Relativistic Magnetic Reconnection: Dependence on Plasma Beta and Magnetization
- The role of electron heating physics in images and variability of the Galactic Centre black hole Sagittarius A*
- Plasmoid formation in global GRMHD simulations and AGN flares
- Constraining particle acceleration in Sgr A* with simultaneous GRAVITY, Spitzer, NuSTAR and Chandra observations
- Magnetic reconnection and plasmoid formation in three-dimensional accretion flows around black holes
- Simultaneous X-ray and Infrared Observations of Sagittarius A*'s Variability
- Electron and Proton Heating in Transrelativistic Guide Field Reconnection
- A Plasmoid Model for the Sgr A* Flares Observed with GRAVITY and Chandra
- The Mechanism of Electron Injection and Acceleration in Trans-Relativistic Reconnection
- A Possible Model for the Long-Term Flares of Sgr A*
- VHE Emission from Magnetic Reconnection in the RIAF of SgrA*
- A Deep Chandra View of A Candidate Parsec-Scale Jet from the Galactic Center Super-massive Black Hole
- Energy Extraction via Magnetic Reconnection in the Ergosphere of a rotating non-Kerr Black Hole
- A "coronal-mass-ejection'' model for flares in Sagittarius A*
- Simultaneous Monitoring of X-ray and Radio Variability in Sagittarius A*
- Multi-wavelength Variability of Sagittarius A* in July 2019
- A Systematic Chandra study of Sgr A: II. X-ray flare statistics
- Radiative shock oscillation model for the long-term flares of Sgr A*
- Synchrotron Polarization Radiative Transfer: Relativistic Thermal Electrons Contribution
- Time delays between radio and X-ray and between narrow radio bands of Sgr A* flares in the shock oscillation model
- Possible evidence from the flaring activity of Sgr A* for a star at a distance of ~3.3 Schwarzscild radii from the blackhole
- Compact and variable radio emission from an active galaxy with supersoft X-ray emission
- A 149 minute periodicity underlies the X-ray flaring of Sgr A*