The Abundance Inhomogeneity in the Northern Rim of the Cygnus Loop
  We observed the northern rim of the Cygnus Loop with the \textit{Suzaku}
observatory in 5 pointings (P21-P25). From the spatially resolved analysis, all
the spectra are well fitted by the single component of the non-equilibrium
ionization plasma model. From the best-fit parameters, we found that the
abundances of the heavy elements are significantly lower than the solar values
except those at the outermost edge in P21 and P22. The origin of the depleted
metal abundances is still unclear while such deficiencies have been reported
from many other rim observations of the Loop. To explain these depletion at the
rim regions, we considered the several possibilities. The effects of the
resonance-line-scattering and the grain condensation lower the values of the
abundances. However, these are not sufficient to account for the abundance
depletion observed.
  We found that the abundances at the outermost edge in P21 and P22 are higher
than those at the other regions. From the morphological point of view, it is
reasonable to consider that this abundance inhomogeneity is derived from the
breakout or the thinness of the cavity wall of the Loop.
