High Energy Sky with Advancing Technology The Galactic Center View From Tenma--Suzaku Hakucho (1979)96 kg Tenma (1983) 216kg Ginga ( 1987 ) 420 kg ASCA ( 1993 ) 417 kg Suzaku (2005) 1600 kg
Si S Fe Tenma: Gas Scintilation Proportional Counter (2 times better resolution) We found Kα lines from highly ionized Fe, S and Si in the Galactic Ridge Presence of High temperature plasma 6.7 keV line
Ginga (large proportional counter) surveyed the Glactic Plane with the 6.7 keV and continuum found excess emision at the Galactic Center GC 2-10 keV band flux (log scale) Fe K-line (6.7 keV) flux (linear scale) Galactic longitude at b=0 deg
The Closed-up View Near the Galactic Center ○ The 6.7 keV line region is extended Center Energy =6.7 keV He-like iron (West) Center Energy < 6.7 keV (East) 2-10 keV 6.7 keV line Beam size Center Energy
ASCA (X-ray CCD + Telescope) separated the K-shell lines into the 6.7 (He-like), 7.0 (H-like) and 6.4 keV (neutral) lines We found 6.4 keV clumps at the molecular clouds, Sgr B and Sgr A. ---> puzzle is solved. The spectrum has strong iron line and large absorption near the iron K-edge at 7.1 keV. Fluorescence by external X- rays No bright X-ray source is found The illuminating source was bright in the past, but faint at present
The Center of the Galaxy in the Recent Past: A view from GRANAT Sunyaev et al. 1993, ASCA View of Our Galactic Center: Remains of Past Activities in X-Rays? Koyama et al., 1996, PASJ, 48. Rasid Sunyaev and I met with each other with the same idea.
Suzaku found K α lines of highly ionized Ar, Ca, Cr, Mn, Fe and Ni (red) and those of neutral (blue ) :Z= 1.6 solar 4 solar The EWs ( absolute values and distribution pattern) are consistent with the X-ray fluorescent origin from clouds of 1.6 solar abundances. Electron origin requires more than 4 solar for all elements !
l-distribution of the 6.4 keV lines Sgr A Discoveries of New 6.4 keV Clouds Sgr B2 Sgr B1 M M M M M M M Arches G G
1994 年 2004 年 2005 年 2000 年 Rapid Time-Varaibility of Sgr B2 6.4 keV line :Koyama et al. 2008, Inui et al. 2009, Hard X-rays :Terrier et al ASCA XMM-Newton Chandra Suzaku
Suzaku found simultaneous variablity of the 6.4 keV line & Hard X-rays in Sgr B The rapid/simultaneous variability strongly supports the X-ray fluorescence origin irradiated by an external big but short X-ray flare. What is the external flare ?
Parabola x 2 +y 2 =(300-y) 2 (Unit is light-year) Sgr A* Flare ~300 years ago Fermi bubble ? Quasar-like activity 1Myears ago ( Su, M. et al. 2010) Face-on View of the 6.4 keV cloud (e.g. Ryu et al. 2009) Near side GCDX is not absorbed by the cloud, while far side is heavily absorbed by the cloud. => Face on position of the cloud
The END