  With 91 months of the publicly available Fermi-LAT Pass 8 data, we analyze
the gamma-ray emission from the Milky Way satellites to search for potential
line signals due to the annihilation of dark matter particles into double
photons. The searched targets include a sample of dwarf spheroidal galaxies,
the Large Magellanic Cloud (LMC) and Small Magellanic Cloud (SMC). No
significant line emission has been found neither in the stacked dwarf galaxy
sample nor in the direction of LMC/SMC. The corresponding upper limits on the
cross section of DM annihilation into two photons are derived. Compared with
results of previous gamma-ray line searches with the Pass 7 data, the current
constraints on the line emission from dwarf spheroidal galaxies has been
significantly improved in a wide energy range. With the rapid increase of the
sample of dwarf spheroidal galaxies (candidates), we expect that the
sensitivity of gamma ray line searches will be significantly improved in the
near future.
