SIMBAD references

Maser stars have been found with radial velocities up to +350km/s and down to -350km/s and exclusively within a few degrees from the Galactic centre. They form two spatially separated streams: one stream is at positive longitudes and consists of stars going away from us and the other is at negative longitudes consisting of stars approaching us. I show that closed orbits in a simple mass model for the bar explain quantitatively the existence of the two streams and the velocities observed. The mass of the bar is estimated on dynamical grounds: 3x10¹⁰M_sun.