Kinematics of Galactic Disc

Abstract

The method of constructing of rotation curve for our galactic disc is discussed. Simple physical model shows that the velocity of the Sun around the center of the Galaxy must be less than currently accepted IAU value 220 km/s. Independently obtained result for neutral hydrogen (λ= 21.1 cm) confirms the previous statement. The values of the Sun's velocity is about 110 km/s. As a consequence, the rotation curve for the disc of our Galaxy is not flat, but it is a decreasing function of the distance from the center of the Galaxy. This conclusion seems to be consistent also with other galaxies.