The K-shell Line Distribution of Heavy Elements along the Galactic Plane Observed with Suzaku

We report the global distribution of the intensities of the K-shell lines from the He-like and H-like ions of S, Ar, Ca and Fe along the Galactic plane. From the profiles, we clearly separate the Galactic center X-ray emission (GCXE) and the Galactic ridge X-ray emission (GRXE). The intensity profiles of the He-like K$\alpha$ lines of S, Ar, Ca and Fe along the Galactic plane are approximately similar with each other, while not for the H-like Ly$\alpha$ lines. In particular, the profiles of H-like Ly$\alpha$ of S and Fe show remarkable contrast; a large excess of Fe and almost no excess of S lines in the GCXE compared to the GRXE. Although the prominent K-shell lines are represented by $\sim$1 keV and $\sim$7 keV temperature plasmas, these two temperatures are not equal between the GCXE and GRXE. In fact, the spectral analysis of the GCXE and GRXE revealed that the $\sim$1 keV plasma in the GCXE has lower temperature than that in the GRXE, and vice versa for the $\sim$7 keV plasma.Comment: Accepted by PASJ. It will be published in PASJ Vol.65 No.

Estimation of Exit Behaviors--Panel Data Analysis of an Experiment with Intergroup Mobility

We estimate exit behavior in a repeated social dilemma situation with intergroup mobility, using experimental data. Estimated results show that absolute levels of cooperation of others in one’s own group is a significant determinant. Also, the difference between the absolute levels of cooperation and the cooperation index based on a subject’s actual choices for cooperation, from the first some periods, is significant. Information about other groups is not important. Based on these results, we draw the following conclusions: (1) subjects care about the information concerning their own group. (2) the higher the cooperation index for a subject, the higher is the probability that he/she will move, given the same level of cooperation of others.

Global Distribution of Fe K alpha Lines in the Galactic Center Region Observed with the Suzaku Satellite

We have surveyed spatial profiles of the Fe K$\alpha$ lines in the Galactic center diffuse X-rays (GCDX), including the transient region from the GCDX to the Galactic ridge X-ray emission (GRXE), with the Suzaku satellite. We resolved Fe K$\alpha$ line complex into three lines of Fe \emissiontype{I}, Fe \emissiontype{XXV} and Fe \emissiontype{XXVI} K$\alpha$, and obtained their spatial intensity profiles with the resolution of \sim \timeform{0D.1}. We compared the Fe \emissiontype{XXV} K$\alpha$ profile with a stellar mass distribution (SMD) model made from near infrared observations. The intensity profile of Fe \emissiontype{XXV} K$\alpha$ is nicely fitted with the SMD model in the GRXE region, while that in the GCDX region shows $3.8\pm0.3$ (\timeform{0D.2}<|l|<\timeform{1D.5}) or $19\pm6$ (|l|<\timeform{0D.2}) times excess over the best-fit SMD model in the GRXE region. Thus Fe \emissiontype{XXV} K$\alpha$ in the GCDX is hardly explained by the same origin of the GRXE. In the case of point source origin, a new population with the extremely strong Fe \emissiontype{XXV} K$\alpha$ line is required. An alternative possibility is that the majority of the GCDX is truly diffuse optically thin thermal plasma.Comment: Accepted by PAS

Suzaku Observations of the Great Annihilator and the Surrounding Diffuse Emissions

We report the Suzaku observation of 1E 1740.7-2942, a black hole candidate called the "Great Annihilator" (GA). The high-quality spectrum of Suzaku provides the severest constraints on the parameters of the GA. Two clumpy structures are found around the GA in the line images of FeI Kalpha at 6.4 keV and SXV Kalpha at 2.45 keV. One clump named M359.23-0.04 exhibits the 6.4-keV line with an equivalent width of ~ 1.2 keV, and is associated with a molecular cloud in the radio CS(J=1-0) map. Thus the 6.4-keV line from M359.23-0.04 is likely due to X-ray fluorescence irradiated by an external X-ray source. The irradiating X-rays would be either the past flare of Sagittarius A* or the bright nearby source, the GA. The other clump named G359.12-0.05 is associated with the radio supernova remnant candidate G359.07-0.02. We therefore propose that G359.12-0.05 is an X-ray counterpart of G359.07-0.02. G359.12-0.05 has a thin thermal plasma spectrum with a temperature of kT ~ 0.9 keV. The plasma parameters of G359.12-0.05 are consistent with those of a single supernova remnant in the Galactic center region.Comment: 10 pages, 8 figures, accepted for publication in PASJ (Vol.62, No.4