  We investigate the gravitational constraints imposed to dark matter halos in
the context of finite temperature scalar field dark matter. We find constraints
to produce multiple images by dark matter only, we show that there are
differences with respect to the full Bose Einstein condensate halo when the
temperature of the scalar field in dark matter halos is taken into account. The
non zero temperature allows the scalar field to be in excited states and
recently, their existence has proved to be necessary to fit rotation curves of
dark matter dominated galaxies of all sizes, it also explained the non
universality of the halo density profiles. Therefore, we expect that combining
observations of rotation curves and strong lensing systems can give us a clue
to the nature of dark matter. Finally, we propose a method to identify the
excited state of a strong lens halo, knowing various halo excited states can
provide information of the scalar field dark matter halo evolution which can be
tested using numerical simulations.
