XMM-Newton Observations of G32.45+0.1 and G38.55+0.0: Diffuse Hard X-Ray Sources Found by the ASCA Galactic Plane Survey

We report on XMM-Newton observations of G32.45+0.1 and G38.55+0.0. These werediscovered as diffuse hard X-ray sources with the ASCA Galactic plane survey,but the limited spatial resolution of ASCA could not conclude whether these aretruly diffuse or a group of unresolved point-sources. XMM-Newton, with higherspatial resolution than ASCA, confirmed that G32.45+0.1 has a diffuseshell-like structure with a radius of ~4'. The spectrum shows featurelesscontinuum, hence can be fitted with a power-law model of Gamma ~2.2 with anabsorption of N_H~5.2*10^{22}cm^{-2}. From this N_H value, we estimate thedistance to G32.45+0.1 to be ~17kpc, then the luminosity (in the 0.5-10.0keVband) and radius of the shell are ~9.5*10^{34}ergs/s and ~20pc, respectively.The radio complex sources in the NRAO/VLA Sky Survey (NVSS; 1.4GHz) areglobally associated to the X-ray shell of G32.45+0.1. Therefore G32.45+0.1 islikely to be a synchrotron dominant shell-like SNR. No significant diffusestructure was found in the XMM-Newton image of another ASCA diffuse sourceG38.55+0.0. The upper limit of the observed flux (0.5-10.0keV) is estimated tobe 9.0*10^{-13}ergs/cm^2/s being consistent with the ASCA result.Comment: Accepted for publication in Publications of the Astronomical Society of Japan, 12 pages, 5 figure