X-ray source population of the Galactic center region obtained with ASCA

Masaaki Sakano(1), Katsuji Koyama(2), Hiroshi Murakami(2), Yoshitomo Maeda(3), Shigeo Yamauchi(4), The ASCA Galactic plane/center survey team

Paper: proc of "New Century of X-ray Astronomy", 6-8 March 2001, Yokohama, Japan

Weblink: http://www-maxi.tksc.nasda.go.jp/%7Esakano/work/paper/index-e.html#Sakano2001asca2001

EPrint Server: astro-ph/0107444

From the ASCA X-ray point-source list in the Galactic center 5* 5 degree² region, we found the clear correlation between the position of the sources and the absorption. This fact implies that the major part of the absorption is due to the cold interstellar matter (ISM) in the line of sight. Using the correlation, we estimate the distribution of the cold ISM. We also found that the ratio of high mass binaries to low mass binaries is significantly smaller than that in the whole Galaxy or SMC, which implies that the past starburst activity in the Galactic center region was rather quiet.