Radial Variations of the Volume- and Surface-Star Formation Laws in the
  Galaxy
  Variation of the volume- and surface-Schmidt laws (star-formation or SF law)
with the galacto-centric distance R was investigated using 3D distributions of
HII regions, HI, and molecular (H_2) gases in the Milky Way. Both the power-law
index and SF coefficient were found to be variable with R. The index is flatter
in the inner disc than in the outer Galaxy, and the coefficient is larger in
the inner disc, decreasing steeply outward. There is also a mutual
anti-correlation between the index and SF coefficient, and the SF law can be
expressed by a single-parameter function of the SF coefficient. The variable SF
law is discussed in relation to the self-regulation star formation.
