Diffuse X-ray emission around the Galactic Center

We represent ASCA/GIS results of the diffuse X-ray emission around the Galactic Center (hereafter GC) region of angular size of about 10 degree. From the observed fields, we found diffuse emissions with K-shell transition lines from highly ionized silicon, sulphur, argon, calcium and/or iron. These give firm evidence for the presence of a thin thermal plasma. With the flux distribution of each line, we conclude that the diffuse X-ray plasma exhibits lower temperature at larger Galactic latitude than that at smaller latitude.