Simulation of a strategy for the pixel lensing of M87 using the Hubble
  Space Telescope
  In this work, we propose a new strategy for the pixel-lensing observation of
M87 in the Virgo cluster using the {\it Hubble Space Telescope} (HST). In
contrast to the previous observational strategy by Baltz et al., we show that a
few days intensive observation with the duration of $\sim 90 $min in each HST
orbit will increase the observational efficiency of the high-magnification
events by more than one order of magnitude. We perform a Monte-Carlo simulation
for this strategy and we show that the number of high magnification
microlensing events will increase at the rate of 4.2 event per day with a
typical transit time scale of 16 h. We also examine the possibility of
observing mini-halo dark matter structures using pixel lensing.
