A Possible Time-Delayed Brightening of the Sgr A* Accretion Flow after the Pericenter Passage of G2 Cloud

Abstract

A possibility of time-delayed radio brightenings of Sgr A* triggered by the pericenter passage of the G2 cloud is studied by carrying out global three-dimensional magnetohydrodynamic simulations taking into account the radiative cooling of the tidal debris of the G2 cloud. Magnetic fields in the accretion flow are strongly perturbed and re-organized after the passage of G2. We have found that the magnetic energy in the accretion flow increases by a factor 3-4 in 5-10 years after the pericenter passage of G2 by a dynamo mechanism driven by the magneto-rotational instability. Since this B-field amplification enhances the synchrotron emission from the disk and the outflow, the radio and the infrared luminosity of Sgr A* is expected to increase around A.D. 2020. The time-delay of the radio brightening enables us to determine the rotation axis of the preexisting disk.

accepted for publication in PASJ

References in corpus (7)

• Hot Accretion Flows Around Black Holes
• Radio and Millimeter Monitoring of Sgr A*: Spectrum, Variability, and Constraints on the G2 Encounter
• Detection of Galactic Center source G2 at 3.8 $\mu$m during periapse passage
• The Galactic Center cloud G2 and its gas streamer
• Possible Origin of the G2 Cloud from the Tidal Disruption of a Known Giant Star by Sgr A*
• 3D adaptive mesh refinement simulations of the gas cloud G2 born within the disks of young stars in the Galactic Center
• No Microwave Flare of Sagittarius A* around the G2 Periastron Passing

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• Cosmic Magnetism in Centimeter and Meter Wavelength Radio Astronomy
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• A Swift study of long-term changes in the X-ray flaring properties of Sagittarius A*
• A Proper Discretization of Hydrodynamic Equations in the Cylindrical Coordinates for Astrophysical Simulations
• Monitoring the Size and Flux Density of Sgr A* during the Active State in 2019 with East Asian VLBI Network