The dwarf spheroidal galaxies (dSphs) in the Milky Way are ideal sites in the indirect
searches for particle dark matter. To set robust constraints on candidate dark matter
particles, understanding the dark halo structure of these systems is of substantial
importance. However, there are three major crucial uncertainties of estimation of their
dark halo structures.
(1) Non-sphericity of dark halo
(2) Effects of contaminations from the Galactic halo stars
(3) Velocity anisotropy of dSph’s stars
In order to address these issues and to obtain more reliable and realistic limits on
dark halo structures, we construct new dynamical models with taking into account the
effects of non-sphericity and contamination. In this talk, I present the effect of these
uncertainties on estimates of dark halo structures in the dSphs and the constraints on
dark matter particles for the case of their annihilation. I also show that Prime Focus
Spectrograph mounted on Subaru telescope will play an important role in getting an
insight into the nature of dark matter particles by synergy with space
telescopes. Moreover, I would like to propose and discuss the synergy between our
dynamical analysis for dSphs and the future X-ray observation (XARM) to obtain robust
limits on decaying dark matter such as sterile neutrinos.