New evidence of the past activity in the Galactic center region

We propose a 30 ksec XMMNewton observation of very enigmatic diffuse structureat 1.5 degree south from the Galactic center. We first discovered this structurewith ROSAT. Then with ASCA, we found that the spectrum exhibits thin thermalemission accompanied with a hard tail which may be nonthermal radiation fromhigh energy electrons. These results imply presence of a strong shock in thisregion, possibly due to a jet from Sgr A*, which was active in the past 10^4years ago. With the observation of XMMNewton, we obtain the richest statisticsever achieved. Then we will reveal the shock front from the image, and verifythe origin from the temperature and the brightness distribution. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]