“…All the theoretical models used to describe the observables obtained from accretion disks rely on the mathematical description of the motion of test particles and viscous plasma fluid in the surroundings of the black hole candidate. However, the motion of test particles may be influenced by a e-mail: bobir.toshmatov@nu.edu.kz (corresponding author) b e-mail: rahimov@astrin.uz c e-mail: ahmedov@astrin.uz d e-mail: daniele.malafarina@nu.edu.kz a large number of factors, including, for example, the geometry [5][6][7][8], the presence of external fields [9,10], the spin of the particles [11][12][13][14][15] and possible deviations from classical general relativity [16,17].…”