Suzaku Metal Abundance Patterns in the Outflow Region of M82 and the
  Importance of Charge Exchange
  We performed spectral analysis of Suzaku data of the galactic disk and
outflow regions of the starburst galaxy M82. Thermal modeling of the central
disk regions requires at least three temperature components. The Ly$\beta$ line
fluxes of O VIII and Ne X exceed those expected from a plasma in collisional
ionization equilibrium. The ratios of Ly$\beta$/Ly$\alpha$ lines for O VIII and
Ne X are higher than those of collisional ionization equilibrium, which may be
caused by the process of charge exchange. In the outflow wind region, the
spectra are well reproduced with two-temperature thermal models, and we have
derived the metal abundances of O, Ne, Mg, and Fe in the outflow. The ratios of
O/Fe, Ne/Fe, and Mg/Fe are about 2, 3, and 2, respectively, relative to the
solar value determined by Lodders (2003). Since there is no evidence of charge
exchange in outflow region, the metal abundances should be more reliable than
those in the central region. This abundance pattern indicates that starburst
activity enriches the outflow through SN II metal ejection into intergalactic
space.
