The gas distribution in the central region of the Galaxy. III - A barlike model of the inner-Galaxy gas based on improved H I data

The morphology and kinematics of gas lying within 2 kpc of the galactic nucleus in terms of material confined to a barlike structure which is tilted 24 deg with respect to the rotation axis of the Galaxy at large is discussed. The model embodies only motions along closed elliptical paths and thereby involves no net flow of mass out of the inner regions of the Galaxy. Angular momentum is conserved because the motions obey the equal-areas law. As with the circular model employed earlier in this series of papers, the tilted-bar model accounts for the appearance of a diverse assortment of individual condensations in position-velocity maps, such as the nuclear disk, the connecting arm, the molecular ring, and other discrete features usually considered to have been ejected from the core of the Galaxy. The model accounts for these features without any local kinematic perturbations or density enhancements.