ASCA View of Our Galactic Center: Remains of Past Activities in X-Rays?
K. KOYAMA^1 Y. MAEDA^1 T. SONOBE^2 T. TAKESHIMA^3, Y. TANAKA^4,2 and S. YAMAUCHI^5
(1) Department of Physics, Kyoto University, Sakyo-ku, Kyoto 606-01,
(2) Institute of Space & Astronautical Science, 3-1-1 Yoshinodai, Sagamihara, Kanagawa 229,
(3) Laboratory for High Energy Astrophysics, Code 668, NASA/GSFC, Greenbelt, MD 20771, USA,
(4) Max-Planck Institut f\"ur Extraterrestrische Physik, D-85748 Garching, Germany,
(5) College of Humanities & Social Science, Iwate University, 3-18-34 Ueda, Morioka, Iwate 020
Paper: to appear in PASJ, Vol. 48 (1996)
Detailed X-ray images and spectra of the Galactic-center region up to
10 keV were obtained with ASCA.
Diffuse thermal-emission with distinct Kalpha lines from highly
ionized ions of various elements has confirmed the presence of an extended
The fluorescent X-ray emission from cold iron atoms in molecular clouds was
also found, possibly due to irradiation by X-rays from the center, which
was bright in the past, but is presently dim.
The results suggest that the Galactic center exhibited intermittent
activities with a time-averaged energy generation rate comparable to
Seyfert nuclei, a class of active galactic nuclei.
Preprints available from the authors at firstname.lastname@example.org
or the raw TeX (no figures) if you click here.
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