On the motions of the sun, the Galaxy and the Andromeda nebula

An attempt is made to discuss a determination of the velocity of the Galaxy with respect to the center of mass of the Local Group and the circular velocity of its rotation at the sun. A statistical method is presented in detail, and an application to the Local Group is outlined. Based on the results obtained, values are recommended for the circular velocity of the Galaxy's rotation at a galactocentric distance of 10 kpc (290 km/s), the maximum circular velocity in the Galaxy's 21-cm rotation curve (about 295 km/s), the masses of the Galaxy (440 billion solar masses) and Andromeda (350 billion solar masses), the velocity of the Galaxy with respect to the center of mass of the Local Group, and three unidentified parameters of the Galaxy with respect to the center of mass of the Local Group, and three unidentified parameters of the Galaxy. It is concluded that: (1) the Galaxy moves mainly toward the sun and slightly downward toward the South Galactic Pole; (2) the Local Group appears to be bound, and its members obey the virial theorem in a statistical sense; and (3) the galactic masses required are smaller than those suggested by Halo advocates.