  The influence of rotation and magnetic fields on the physical properties of
isothermal gas clouds is discussed. The presence of rotation and/or magnetic
fields results in an increase of the critical cloud mass with respect to
gravitational instability for clouds of a given temperature and external
pressure. Rotating clouds have higher densities. Consequently, they are more
stable against tidal shear than non-rotating clouds. They can approach the
Galactic Centre up to a radius of ~2 pc without being disrupted by the tidal
shear due to the gravitational potential. For smaller radii the clouds either
collapse or become tidally disrupted. We suggest that this mechanism is
responsible for the formation of the inner edge of the Circumnuclear Disk in
the Galactic Centre.

Astrophysics