Chandra Observations of Diffuse X-Rays from the Sagittarius B2 Cloud

Hiroshi Murakami(1), Katsuji Koyama(1), Yoshitomo Maeda(2,3)

(1) Department of Physics, Faculty of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan; hiro@cr.scphys.kyoto-u.ac.jp, koyama@cr.scphys.kyoto-u.ac.jp
(2) Department of Astronomy and Astrophysics, The Pennsylvania State University, 525 Davey Lab. University park, PA 16802; maeda@astro.psu.edu
(3) Subaru Telescope, National Astronomical Observatory of Japan, 650 North Aohoku Place, Hilo, HI 96720

Paper: ApJ, accepted

EPrint Server: astro-ph/0105273

Abstract:

We present the first Chandra results of the giant molecular cloud Sagittarius B2 (Sgr B2), located about 100 pc away from the Galactic center. Diffuse X-rays are clearly separated from one-and-a-half dozen resolved point sources. The X-ray spectrum exhibits pronounced iron K-shell transition lines at 6.40 keV (K alpha ) and 7.06 keV (K beta ), deep iron K-edge at 7.11 keV and large photo-electric absorption at low energy. The absorption-corrected X-ray luminosity is 1*10³⁵ erg s^-1, two orders of magnitude larger than the integrated luminosity of all the resolved point sources. The diffuse X-rays come mainly from the south-west half of the cloud with a concave-shape pointing to the Galactic center direction. These results strongly support the ASCA model that Sgr B2 is irradiated by an X-ray source at the Galactic center side.

Preprints available from the authors at hiro@cr.scphys.kyoto-u.ac.jp , or the raw TeX (no figures) if you click here.

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