Recently , near-infrared GRAVIY @ ESO observations at 2.2 \mu { m } have announced the detection of three bright “ flares ” in the vicinity of the Galactic center black hole that exhibited orbital motion at the radius about 6 - 11 gravitational radii of 4.14 \times 10 ^ { 6 } M _ { \odot } black hole .
There are indications of the presence of a large-scale , organized component of the magnetic field at the Galactic center .
Electromagnetic effects on the flare dynamics were previously not taken into account despite that the relativistic motion of a plasma in magnetic field leads to the charge separation and non-negligible net charge density in the plasma .
Applying various approaches we find the net charge number density of the flare components of the order of 10 ^ { -3 } -10 ^ { -4 } cm ^ { -3 } , while the particles total number density is of the order of 10 ^ { 6 } -10 ^ { 8 } cm ^ { -3 } .
However , even such a tiny excess of charged particles in the quasi-neutral plasma can sufficiently affect the dynamics of flare components , which can then lead to discrepancies in the measurements of spin of the supermassive black hole .
Analyzing the dynamics of recent flares in the case of the rapidly rotating black hole a > 0.5 , we also constrain the inclination angle between magnetic field and the spin axis to \alpha < 50 ^ { \circ } , as for larger angles the motion of the hot spot is strongly chaotic .