We discuss scenarios in which the galactic dark matter in spiral galaxies i
s described by a long range coherent field which settles in a stationary co
nfiguration that might account for the features of the galactic rotation cu
rves. The simplest possibility is to consider scalar fields, so we discuss,
in particular, two mechanisms that would account for the settlement of the
scalar field in a nontrivial configuration in the absence of a direct coup
ling of the field with ordinary matter: topological defects and spontaneous
scalarization.