Constraining SuperWIMPy and Warm Subhalos with Future Submillilensing
  We propose to observe QSO-galaxy strong lens systems to give a new constraint on the damping scale of the initial fluctuations. We find that the future observation of submilliarc scale astrometric shifts of the multiple lensed images of QSOs would find \sim 10^{(3-9)} M_{\odot} subhalos inside the macrolens halo. The superweakly interacting massive particles (superWIMPs) produced from a WIMP decay and the warm dark matter (WDM) particles that predict a comoving damping scale larger than \sim 2 kpc can be constrained if \sim 10^3 M_{\odot} subhalos are detected. 
Junji Hisano, Kaiki Taro Inoue and Tomo Takahashi