2019ApJ...870..107D

The density and mass of the spiral galaxy NGC 3198 have been studied as functions of the distance from the center of galaxy depending on its observed rotation curve. Calculation of density and mass at different radii of the galaxy NGC 3198 show that the central inner density ρ1(r) at r < r_t (r_t is the turn-off radius) is found to be constant ρ1 = 0.387 M_o pc^–3, while the density ρ2(r) of the outer region r > r_t is much less than the inner region, which varies from 0.0187 M_o pc^–3 at r = 4 kpc to 0.00278 M_o pc^–3 at r = 30 kpc. On the other hand, the inner mass m1(r) at r < r_t grows from 1.33 x 10⁹ M_o at r = 0.1 kpc to a mass of 8.539 x 10⁹ M_o at r = 4 kpc, while the outer mass m2(r) at r >= r_t changes from 8.539 x 10⁹ M_o at the turn-off radius r_t to 5.262 x 10¹⁰ M_o at r = 30 kpc of the galaxy. Finally, the behavior of the calculated density and mass is consistent with other works.