ON THE POSSIBILITY OF APPLYING THE QUASI-ISOTHERMAL ST˜ ACKEL'S MODEL TO OUR GALAXY

Received: 2015 March 25; accepted: 2015 April 20Abstract. An earlier derived quasi-isothermal St˜ackel’s model of mass distri-bution in stellar systems and the corresponding formula for space density areapplied to our Galaxy. The model rotation curve is fltted to HI kinematicaldata. The structural and scale parameters of the model are estimated and thecorresponding density contours for our Galaxy are presented.Key words: methods: analytical { Galaxy: kinematics and dynamics1. INTRODUCTIONThere are various methods for modeling the gravitational potential of ourGalaxy and other stellar systems. One of them is based on the assumption thatthe potential is of the St˜ackel’s form. After pioneering works by Kuzmin (1952,1956) the method was further developed by de Zeeuw et al. (1986), Dejonghe &de Zeeuw (1988), and others. In this paper we study the possibility of using thequasi-isothermal potential suggested by Kuzmin et al. (1986) for constructing aSt˜ackel’s model of our Galaxy.For systems with St˜ackel’s potentials the third integral of motion is known toexist in the form of a function that depends quadratically on velocities: