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Register a new userSuzaku Observation of Diffuse X-Ray Emission from a Southwest Region of the Carina Nebula
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A southwest region of the Carina nebula was observed with the Suzaku observatory for 47 ks in 2010 December. This region shows distinctively soft X-ray emission in the Chandra campaign observations. Suzaku clearly detects the diffuse emission above known foreground and background components between 0.4-5 keV at the surface brightness of 3.3x10^-14 erg s^{-1} arcmin^{-2}. The spectrum requires two plasma emission components with kT~0.2 and 0.5 keV, which suffer interstellar absorption of N_H~1.9x10^{21} cm^{-2}. Multiple absorption models assuming two temperature plasmas at ionization equilibrium or non-equilibrium are tested but there is no significant difference in terms of chi^2/d.o.f.. These plasma temperatures are similar to those of the central and eastern parts of the Carina nebula measured in earlier Suzaku observations, but the surface brightness of the hot component is significantly lower than those of the other regions. This means that these two plasma components are physically separated and have different origins. The elemental abundances of O, Ne and Mg with respect to Fe favor that the diffuse plasma originates from core-collapsed supernovae or massive stellar winds.
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We present the analysis of Suzaku observations of the young open cluster Westerlund 2, which is filled with diffuse X-ray emission. We found that the emission consists of three thermal components or two thermal and one non-thermal components. The upper limit of the energy flux of the non-thermal component is smaller than that in the TeV band observed with H.E.S.S. This may indicate that active particle acceleration has stopped in this cluster, and that the accelerated electrons have already cooled. The gamma-ray emission observed with H.E.S.S. is likely to come from high-energy protons, which hardly cool in contrast with electrons. Metal abundances of the diffuse X-ray gas may indicate the explosion of a massive star in the past.
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