  Galactic dark matter halos may be composed of ultralight axions (ULAs) ($m_a
\lesssim 1$ eV) with wave functions that satisfy nonlinear
Schr\"{o}dinger-Poisson equations (SPA). We find eigenstates of SPA in WKB
approximation. The expansion parameter of the WKB approximation is
$\delta=1/\sqrt{S}$, where $S=2 M R G m_a^{2}$, with $M$ being the total mass,
$R$ the radius of the halo, and $G$ the gravitational constant. $S\gg 1$ for
almost all galaxies, even if the ULA mass is as small as $m_a=10^{-22} $ eV,
making the leading order WKB approximation almost exact. As the level spacing
of bound states is roughly proportional to $\delta$, the number of states in
the gravitational well is huge. We do not see a reason why not all or most of
them contribute to the halo. Using an appropriate distribution function allows
the summation of states to construct the profile of the halo as a function of
the gravitational potential, which can be found solving the Poisson equation.
Using various energy distribution functions, we obtain results similar to those
in simulations. Future plans include investigations of collapse through time
dependent generalizations, and inclusion of self-interactions, which also
induce decay processes of the halo.
