X-ray activities in the Galactic Center Region

With ASCA, we obtained detailed X-ray images and spectra of the Galactic Ce nter. X-rays in the central parsecs from the dynamical center of the Galaxy , Sgr A*, were dominated by extended emission. Since Sgr A* was not spatial ly resolved from the extended structure, an upper limit to its luminosity w as found to be 3 x 10(35) erg s(-1). This result indicates that the current AGN activity of the Galactic nucleus is very low. In the central hundreds of parsecs, X-ray stars, thin thermal diffuse plasma, and iron fluorescent emission from molecular clouds were seen. Based on the analyses of the S-ra y stars and both of the diffuse components, we discuss some features which are possibly related to past nuclear activities.