Suzaku observations of two diffuse hard X-ray source regions, G22.0+0.0 and G23.5+0.1

Abstract

Abstract G22.0+0.0 and G23.5+0.1 are diffuse hard X-ray sources discovered in the ASCA Galactic Plane Survey. We present Suzaku results of spectral analysis for these sources. G22.0+0.0 is confirmed to be a largely extended emission. Its spectra were represented by a highly absorbed power-law model with a photon index of 1.7 ± 0.3 and a moderately absorbed thermal emission with a temperature of 0.34$^{+0.11}_{-0.08}\:$keV. The difference in the NH values between the two components suggests that the thermal component is unrelated to the power-law component and is a foreground emission located in the same line of sight. G23.5+0.1 is an extended source with a size of ∼3${^{\prime}_{.}}$5. Its spectra were fitted with an absorbed power-law model with a photon index of 2.4$^{+0.5}_{-0.4}$. The spatial and spectral properties show that both sources are candidates for old pulsar wind nebulae (PWNe). In addition to the extended sources, we analyzed spectra of three point sources found in the observed fields. Based on the spectral features, we discuss the origin of the sources.